gate apple gpu collectors + revert readme change

The previous behavior only caught some errors including inaccessible
hosts, but not others like failed authentication or service
unavailability. This largely applies when using a socket proxy and
having the retry mitigates some erroneous behavior.

agent/docker.go

@@ -72,6 +72,7 @@ type dockerManager struct {
 	// cacheTimeMs -> DeltaTracker for network bytes sent/received
 	networkSentTrackers map[uint16]*deltatracker.DeltaTracker[string, uint64]
 	networkRecvTrackers map[uint16]*deltatracker.DeltaTracker[string, uint64]
+	retrySleep          func(time.Duration)
 }
 
 // userAgentRoundTripper is a custom http.RoundTripper that adds a User-Agent header to all requests
@@ -565,6 +566,7 @@ func newDockerManager() *dockerManager {
 		lastCpuReadTime:     make(map[uint16]map[string]time.Time),
 		networkSentTrackers: make(map[uint16]*deltatracker.DeltaTracker[string, uint64]),
 		networkRecvTrackers: make(map[uint16]*deltatracker.DeltaTracker[string, uint64]),
+		retrySleep:          time.Sleep,
 	}
 
 	// If using podman, return client
@@ -574,7 +576,7 @@ func newDockerManager() *dockerManager {
 		return manager
 	}
 
-	// this can take up to 5 seconds with retry, so run in goroutine
+	// run version check in goroutine to avoid blocking (server may not be ready and requires retries)
 	go manager.checkDockerVersion()
 
 	// give version check a chance to complete before returning
@@ -594,18 +596,18 @@ func (dm *dockerManager) checkDockerVersion() {
 	const versionMaxTries = 2
 	for i := 1; i <= versionMaxTries; i++ {
 		resp, err = dm.client.Get("http://localhost/version")
-		if err == nil {
+		if err == nil && resp.StatusCode == http.StatusOK {
 			break
 		}
 		if resp != nil {
 			resp.Body.Close()
 		}
 		if i < versionMaxTries {
-			slog.Debug("Failed to get Docker version; retrying", "attempt", i, "error", err)
+			slog.Debug("Failed to get Docker version; retrying", "attempt", i, "err", err, "response", resp)
-			time.Sleep(5 * time.Second)
+			dm.retrySleep(5 * time.Second)
 		}
 	}
-	if err != nil {
+	if err != nil || resp.StatusCode != http.StatusOK {
 		return
 	}
 	if err := dm.decode(resp, &versionInfo); err != nil {

agent/docker_test.go

@@ -5,7 +5,13 @@ package agent
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"strings"
 	"testing"
@@ -379,6 +385,117 @@ func TestDockerManagerCreation(t *testing.T) {
 	assert.NotNil(t, dm.networkRecvTrackers)
 }
 
+func TestCheckDockerVersion(t *testing.T) {
+	tests := []struct {
+		name      string
+		responses []struct {
+			statusCode int
+			body       string
+		}
+		expectedGood     bool
+		expectedRequests int
+	}{
+		{
+			name: "200 with good version on first try",
+			responses: []struct {
+				statusCode int
+				body       string
+			}{
+				{http.StatusOK, `{"Version":"25.0.1"}`},
+			},
+			expectedGood:     true,
+			expectedRequests: 1,
+		},
+		{
+			name: "200 with old version on first try",
+			responses: []struct {
+				statusCode int
+				body       string
+			}{
+				{http.StatusOK, `{"Version":"24.0.7"}`},
+			},
+			expectedGood:     false,
+			expectedRequests: 1,
+		},
+		{
+			name: "non-200 then 200 with good version",
+			responses: []struct {
+				statusCode int
+				body       string
+			}{
+				{http.StatusServiceUnavailable, `"not ready"`},
+				{http.StatusOK, `{"Version":"25.1.0"}`},
+			},
+			expectedGood:     true,
+			expectedRequests: 2,
+		},
+		{
+			name: "non-200 on all retries",
+			responses: []struct {
+				statusCode int
+				body       string
+			}{
+				{http.StatusInternalServerError, `"error"`},
+				{http.StatusUnauthorized, `"error"`},
+			},
+			expectedGood:     false,
+			expectedRequests: 2,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			requestCount := 0
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				idx := requestCount
+				requestCount++
+				if idx >= len(tt.responses) {
+					idx = len(tt.responses) - 1
+				}
+				w.WriteHeader(tt.responses[idx].statusCode)
+				fmt.Fprint(w, tt.responses[idx].body)
+			}))
+			defer server.Close()
+
+			dm := &dockerManager{
+				client: &http.Client{
+					Transport: &http.Transport{
+						DialContext: func(_ context.Context, network, _ string) (net.Conn, error) {
+							return net.Dial(network, server.Listener.Addr().String())
+						},
+					},
+				},
+				retrySleep: func(time.Duration) {},
+			}
+
+			dm.checkDockerVersion()
+
+			assert.Equal(t, tt.expectedGood, dm.goodDockerVersion)
+			assert.Equal(t, tt.expectedRequests, requestCount)
+		})
+	}
+
+	t.Run("request error on all retries", func(t *testing.T) {
+		requestCount := 0
+		dm := &dockerManager{
+			client: &http.Client{
+				Transport: &http.Transport{
+					DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
+						requestCount++
+						return nil, errors.New("connection refused")
+					},
+				},
+			},
+			retrySleep: func(time.Duration) {},
+		}
+
+		dm.checkDockerVersion()
+
+		assert.False(t, dm.goodDockerVersion)
+		assert.Equal(t, 2, requestCount)
+	})
+}
+
 func TestCycleCpuDeltas(t *testing.T) {
 	dm := &dockerManager{
 		lastCpuContainer: map[uint16]map[string]uint64{

agent/gpu.go

@@ -9,6 +9,7 @@ import (
 	"maps"
 	"os/exec"
 	"regexp"
+	"runtime"
 	"strconv"
 	"strings"
 	"sync"
@@ -19,11 +20,13 @@ import (
 
 const (
 	// Commands
-	nvidiaSmiCmd  string = "nvidia-smi"
+	nvidiaSmiCmd    string = "nvidia-smi"
-	rocmSmiCmd    string = "rocm-smi"
+	rocmSmiCmd      string = "rocm-smi"
-	tegraStatsCmd string = "tegrastats"
+	tegraStatsCmd   string = "tegrastats"
-	nvtopCmd      string = "nvtop"
+	nvtopCmd        string = "nvtop"
-	noGPUFoundMsg string = "no GPU found - see https://beszel.dev/guide/gpu"
+	powermetricsCmd string = "powermetrics"
+	macmonCmd       string = "macmon"
+	noGPUFoundMsg   string = "no GPU found - see https://beszel.dev/guide/gpu"
 
 	// Command retry and timeout constants
 	retryWaitTime     time.Duration = 5 * time.Second
@@ -82,15 +85,18 @@ var errNoValidData = fmt.Errorf("no valid GPU data found") // Error for missing
 type collectorSource string
 
 const (
-	collectorSourceNVTop       collectorSource = collectorSource(nvtopCmd)
+	collectorSourceNVTop        collectorSource = collectorSource(nvtopCmd)
-	collectorSourceNVML        collectorSource = "nvml"
+	collectorSourceNVML         collectorSource = "nvml"
-	collectorSourceNvidiaSMI   collectorSource = collectorSource(nvidiaSmiCmd)
+	collectorSourceNvidiaSMI    collectorSource = collectorSource(nvidiaSmiCmd)
-	collectorSourceIntelGpuTop collectorSource = collectorSource(intelGpuStatsCmd)
+	collectorSourceIntelGpuTop  collectorSource = collectorSource(intelGpuStatsCmd)
-	collectorSourceAmdSysfs    collectorSource = "amd_sysfs"
+	collectorSourceAmdSysfs     collectorSource = "amd_sysfs"
-	collectorSourceRocmSMI     collectorSource = collectorSource(rocmSmiCmd)
+	collectorSourceRocmSMI      collectorSource = collectorSource(rocmSmiCmd)
-	collectorGroupNvidia       string          = "nvidia"
+	collectorSourceMacmon       collectorSource = collectorSource(macmonCmd)
-	collectorGroupIntel        string          = "intel"
+	collectorSourcePowermetrics collectorSource = collectorSource(powermetricsCmd)
-	collectorGroupAmd          string          = "amd"
+	collectorGroupNvidia        string          = "nvidia"
+	collectorGroupIntel         string          = "intel"
+	collectorGroupAmd           string          = "amd"
+	collectorGroupApple         string          = "apple"
 )
 
 func isValidCollectorSource(source collectorSource) bool {
@@ -100,7 +106,9 @@ func isValidCollectorSource(source collectorSource) bool {
 		collectorSourceNvidiaSMI,
 		collectorSourceIntelGpuTop,
 		collectorSourceAmdSysfs,
-		collectorSourceRocmSMI:
+		collectorSourceRocmSMI,
+		collectorSourceMacmon,
+		collectorSourcePowermetrics:
 		return true
 	}
 	return false
@@ -108,12 +116,14 @@ func isValidCollectorSource(source collectorSource) bool {
 
 // gpuCapabilities describes detected GPU tooling and sysfs support on the host.
 type gpuCapabilities struct {
-	hasNvidiaSmi   bool
+	hasNvidiaSmi    bool
-	hasRocmSmi     bool
+	hasRocmSmi      bool
-	hasAmdSysfs    bool
+	hasAmdSysfs     bool
-	hasTegrastats  bool
+	hasTegrastats   bool
-	hasIntelGpuTop bool
+	hasIntelGpuTop  bool
-	hasNvtop       bool
+	hasNvtop        bool
+	hasMacmon       bool
+	hasPowermetrics bool
 }
 
 type collectorDefinition struct {
@@ -449,11 +459,19 @@ func (gm *GPUManager) discoverGpuCapabilities() gpuCapabilities {
 	if _, err := exec.LookPath(nvtopCmd); err == nil {
 		caps.hasNvtop = true
 	}
+	if runtime.GOOS == "darwin" {
+		if _, err := exec.LookPath(macmonCmd); err == nil {
+			caps.hasMacmon = true
+		}
+		if _, err := exec.LookPath(powermetricsCmd); err == nil {
+			caps.hasPowermetrics = true
+		}
+	}
 	return caps
 }
 
 func hasAnyGpuCollector(caps gpuCapabilities) bool {
-	return caps.hasNvidiaSmi || caps.hasRocmSmi || caps.hasAmdSysfs || caps.hasTegrastats || caps.hasIntelGpuTop || caps.hasNvtop
+	return caps.hasNvidiaSmi || caps.hasRocmSmi || caps.hasAmdSysfs || caps.hasTegrastats || caps.hasIntelGpuTop || caps.hasNvtop || caps.hasMacmon || caps.hasPowermetrics
 }
 
 func (gm *GPUManager) startIntelCollector() {
@@ -567,6 +585,22 @@ func (gm *GPUManager) collectorDefinitions(caps gpuCapabilities) map[collectorSo
 				return true
 			},
 		},
+		collectorSourceMacmon: {
+			group:     collectorGroupApple,
+			available: caps.hasMacmon,
+			start: func(_ func()) bool {
+				gm.startMacmonCollector()
+				return true
+			},
+		},
+		collectorSourcePowermetrics: {
+			group:     collectorGroupApple,
+			available: caps.hasPowermetrics,
+			start: func(_ func()) bool {
+				gm.startPowermetricsCollector()
+				return true
+			},
+		},
 	}
 }
 
@@ -674,7 +708,10 @@ func (gm *GPUManager) resolveLegacyCollectorPriority(caps gpuCapabilities) []col
 		priorities = append(priorities, collectorSourceIntelGpuTop)
 	}
 
-	// Keep nvtop as a legacy last resort only when no vendor collector exists.
+	// Apple collectors are currently opt-in only.
+	// Enable them with GPU_COLLECTOR=macmon or GPU_COLLECTOR=powermetrics.
+
+	// Keep nvtop as a last resort only when no vendor collector exists.
 	if len(priorities) == 0 && caps.hasNvtop {
 		priorities = append(priorities, collectorSourceNVTop)
 	}

agent/gpu_apple_unsupported.go

@@ -0,0 +1,9 @@
+//go:build !darwin
+
+package agent
+
+// startPowermetricsCollector is a no-op on non-darwin platforms; the real implementation is in gpu_darwin.go.
+func (gm *GPUManager) startPowermetricsCollector() {}
+
+// startMacmonCollector is a no-op on non-darwin platforms; the real implementation is in gpu_darwin.go.
+func (gm *GPUManager) startMacmonCollector() {}

agent/gpu_darwin.go

@@ -0,0 +1,252 @@
+//go:build darwin
+
+package agent
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"io"
+	"log/slog"
+	"os/exec"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/henrygd/beszel/internal/entities/system"
+)
+
+const (
+	// powermetricsSampleIntervalMs is the sampling interval passed to powermetrics (-i).
+	powermetricsSampleIntervalMs = 500
+	// powermetricsPollInterval is how often we run powermetrics to collect a new sample.
+	powermetricsPollInterval = 2 * time.Second
+	// macmonIntervalMs is the sampling interval passed to macmon pipe (-i), in milliseconds.
+	macmonIntervalMs = 2500
+)
+
+const appleGPUID = "0"
+
+// startPowermetricsCollector runs powermetrics --samplers gpu_power in a loop and updates
+// GPU usage and power. Requires root (sudo) on macOS. A single logical GPU is reported as id "0".
+func (gm *GPUManager) startPowermetricsCollector() {
+	// Ensure single GPU entry for Apple GPU
+	if _, ok := gm.GpuDataMap[appleGPUID]; !ok {
+		gm.GpuDataMap[appleGPUID] = &system.GPUData{Name: "Apple GPU"}
+	}
+
+	go func() {
+		failures := 0
+		for {
+			if err := gm.collectPowermetrics(); err != nil {
+				failures++
+				if failures > maxFailureRetries {
+					slog.Warn("powermetrics GPU collector failed repeatedly, stopping", "err", err)
+					break
+				}
+				slog.Warn("Error collecting macOS GPU data via powermetrics (may require sudo)", "err", err)
+				time.Sleep(retryWaitTime)
+				continue
+			}
+			failures = 0
+			time.Sleep(powermetricsPollInterval)
+		}
+	}()
+}
+
+// collectPowermetrics runs powermetrics once and parses GPU usage and power from its output.
+func (gm *GPUManager) collectPowermetrics() error {
+	interval := strconv.Itoa(powermetricsSampleIntervalMs)
+	cmd := exec.Command(powermetricsCmd, "--samplers", "gpu_power", "-i", interval, "-n", "1")
+	cmd.Stderr = nil
+	out, err := cmd.Output()
+	if err != nil {
+		return err
+	}
+	if !gm.parsePowermetricsData(out) {
+		return errNoValidData
+	}
+	return nil
+}
+
+// parsePowermetricsData parses powermetrics gpu_power output and updates GpuDataMap["0"].
+// Example output:
+//
+//	**** GPU usage ****
+//	GPU HW active frequency: 444 MHz
+//	GPU HW active residency:   0.97% (444 MHz: .97% ...
+//	GPU idle residency:  99.03%
+//	GPU Power: 4 mW
+func (gm *GPUManager) parsePowermetricsData(output []byte) bool {
+	var idleResidency, powerMW float64
+	var gotIdle, gotPower bool
+
+	scanner := bufio.NewScanner(bytes.NewReader(output))
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if strings.HasPrefix(line, "GPU idle residency:") {
+			// "GPU idle residency:  99.03%"
+			fields := strings.Fields(strings.TrimPrefix(line, "GPU idle residency:"))
+			if len(fields) >= 1 {
+				pct := strings.TrimSuffix(fields[0], "%")
+				if v, err := strconv.ParseFloat(pct, 64); err == nil {
+					idleResidency = v
+					gotIdle = true
+				}
+			}
+		} else if strings.HasPrefix(line, "GPU Power:") {
+			// "GPU Power: 4 mW"
+			fields := strings.Fields(strings.TrimPrefix(line, "GPU Power:"))
+			if len(fields) >= 1 {
+				if v, err := strconv.ParseFloat(fields[0], 64); err == nil {
+					powerMW = v
+					gotPower = true
+				}
+			}
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return false
+	}
+	if !gotIdle && !gotPower {
+		return false
+	}
+
+	gm.Lock()
+	defer gm.Unlock()
+
+	if _, ok := gm.GpuDataMap[appleGPUID]; !ok {
+		gm.GpuDataMap[appleGPUID] = &system.GPUData{Name: "Apple GPU"}
+	}
+	gpu := gm.GpuDataMap[appleGPUID]
+
+	if gotIdle {
+		// Usage = 100 - idle residency (e.g. 100 - 99.03 = 0.97%)
+		gpu.Usage += 100 - idleResidency
+	}
+	if gotPower {
+		// mW -> W
+		gpu.Power += powerMW / milliwattsInAWatt
+	}
+	gpu.Count++
+	return true
+}
+
+// startMacmonCollector runs `macmon pipe` in a loop and parses one JSON object per line.
+// This collector does not require sudo. A single logical GPU is reported as id "0".
+func (gm *GPUManager) startMacmonCollector() {
+	if _, ok := gm.GpuDataMap[appleGPUID]; !ok {
+		gm.GpuDataMap[appleGPUID] = &system.GPUData{Name: "Apple GPU"}
+	}
+
+	go func() {
+		failures := 0
+		for {
+			if err := gm.collectMacmonPipe(); err != nil {
+				failures++
+				if failures > maxFailureRetries {
+					slog.Warn("macmon GPU collector failed repeatedly, stopping", "err", err)
+					break
+				}
+				slog.Warn("Error collecting macOS GPU data via macmon", "err", err)
+				time.Sleep(retryWaitTime)
+				continue
+			}
+			failures = 0
+			// `macmon pipe` is long-running; if it returns, wait a bit before restarting.
+			time.Sleep(retryWaitTime)
+		}
+	}()
+}
+
+type macmonTemp struct {
+	GPUTempAvg float64 `json:"gpu_temp_avg"`
+}
+
+type macmonSample struct {
+	GPUPower    float64    `json:"gpu_power"`     // watts (macmon reports fractional values)
+	GPURAMPower float64    `json:"gpu_ram_power"` // watts
+	GPUUsage    []float64  `json:"gpu_usage"`     // [freq_mhz, usage] where usage is typically 0..1
+	Temp        macmonTemp `json:"temp"`
+}
+
+func (gm *GPUManager) collectMacmonPipe() (err error) {
+	cmd := exec.Command(macmonCmd, "pipe", "-i", strconv.Itoa(macmonIntervalMs))
+	// Avoid blocking if macmon writes to stderr.
+	cmd.Stderr = io.Discard
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return err
+	}
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+
+	// Ensure we always reap the child to avoid zombies on any return path and
+	// propagate a non-zero exit code if no other error was set.
+	defer func() {
+		_ = stdout.Close()
+		if cmd.ProcessState == nil || !cmd.ProcessState.Exited() {
+			_ = cmd.Process.Kill()
+		}
+		if waitErr := cmd.Wait(); err == nil && waitErr != nil {
+			err = waitErr
+		}
+	}()
+
+	scanner := bufio.NewScanner(stdout)
+	var hadSample bool
+	for scanner.Scan() {
+		line := bytes.TrimSpace(scanner.Bytes())
+		if len(line) == 0 {
+			continue
+		}
+		if gm.parseMacmonLine(line) {
+			hadSample = true
+		}
+	}
+	if scanErr := scanner.Err(); scanErr != nil {
+		return scanErr
+	}
+	if !hadSample {
+		return errNoValidData
+	}
+	return nil
+}
+
+// parseMacmonLine parses a single macmon JSON line and updates Apple GPU metrics.
+func (gm *GPUManager) parseMacmonLine(line []byte) bool {
+	var sample macmonSample
+	if err := json.Unmarshal(line, &sample); err != nil {
+		return false
+	}
+
+	usage := 0.0
+	if len(sample.GPUUsage) >= 2 {
+		usage = sample.GPUUsage[1]
+		// Heuristic: macmon typically reports 0..1; convert to percentage.
+		if usage <= 1.0 {
+			usage *= 100
+		}
+	}
+
+	// Consider the line valid if it contains at least one GPU metric.
+	if usage == 0 && sample.GPUPower == 0 && sample.Temp.GPUTempAvg == 0 {
+		return false
+	}
+
+	gm.Lock()
+	defer gm.Unlock()
+
+	gpu, ok := gm.GpuDataMap[appleGPUID]
+	if !ok {
+		gpu = &system.GPUData{Name: "Apple GPU"}
+		gm.GpuDataMap[appleGPUID] = gpu
+	}
+	gpu.Temperature = sample.Temp.GPUTempAvg
+	gpu.Usage += usage
+	// macmon reports power in watts; include VRAM power if present.
+	gpu.Power += sample.GPUPower + sample.GPURAMPower
+	gpu.Count++
+	return true
+}

agent/gpu_darwin_test.go

@@ -0,0 +1,81 @@
+//go:build darwin
+
+package agent
+
+import (
+	"testing"
+
+	"github.com/henrygd/beszel/internal/entities/system"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParsePowermetricsData(t *testing.T) {
+	input := `
+Machine model: Mac14,10
+OS version: 25D125
+
+*** Sampled system activity (Sat Feb 14 00:42:06 2026 -0500) (503.05ms elapsed) ***
+
+**** GPU usage ****
+
+GPU HW active frequency: 444 MHz
+GPU HW active residency:   0.97% (444 MHz: .97% 612 MHz:   0% 808 MHz:   0% 968 MHz:   0% 1110 MHz:   0% 1236 MHz:   0% 1338 MHz:   0% 1398 MHz:   0%)
+GPU SW requested state: (P1 : 100% P2 :   0% P3 :   0% P4 :   0% P5 :   0% P6 :   0% P7 :   0% P8 :   0%)
+GPU idle residency:  99.03%
+GPU Power: 4 mW
+`
+	gm := &GPUManager{
+		GpuDataMap: make(map[string]*system.GPUData),
+	}
+	valid := gm.parsePowermetricsData([]byte(input))
+	require.True(t, valid)
+
+	g0, ok := gm.GpuDataMap["0"]
+	require.True(t, ok)
+	assert.Equal(t, "Apple GPU", g0.Name)
+	// Usage = 100 - 99.03 = 0.97
+	assert.InDelta(t, 0.97, g0.Usage, 0.01)
+	// 4 mW -> 0.004 W
+	assert.InDelta(t, 0.004, g0.Power, 0.0001)
+	assert.Equal(t, 1.0, g0.Count)
+}
+
+func TestParsePowermetricsDataPartial(t *testing.T) {
+	// Only power line (e.g. older macOS or different sampler output)
+	input := `
+**** GPU usage ****
+GPU Power: 120 mW
+`
+	gm := &GPUManager{
+		GpuDataMap: make(map[string]*system.GPUData),
+	}
+	valid := gm.parsePowermetricsData([]byte(input))
+	require.True(t, valid)
+
+	g0, ok := gm.GpuDataMap["0"]
+	require.True(t, ok)
+	assert.Equal(t, "Apple GPU", g0.Name)
+	assert.InDelta(t, 0.12, g0.Power, 0.001)
+	assert.Equal(t, 1.0, g0.Count)
+}
+
+func TestParseMacmonLine(t *testing.T) {
+	input := `{"all_power":0.6468324661254883,"ane_power":0.0,"cpu_power":0.6359732151031494,"ecpu_usage":[2061,0.1726151406764984],"gpu_power":0.010859241709113121,"gpu_ram_power":0.000965250947047025,"gpu_usage":[503,0.013633215799927711],"memory":{"ram_total":17179869184,"ram_usage":12322914304,"swap_total":0,"swap_usage":0},"pcpu_usage":[1248,0.11792058497667313],"ram_power":0.14885640144348145,"sys_power":10.4955415725708,"temp":{"cpu_temp_avg":23.041261672973633,"gpu_temp_avg":29.44516944885254},"timestamp":"2026-02-17T19:34:27.942556+00:00"}`
+
+	gm := &GPUManager{
+		GpuDataMap: make(map[string]*system.GPUData),
+	}
+	valid := gm.parseMacmonLine([]byte(input))
+	require.True(t, valid)
+
+	g0, ok := gm.GpuDataMap["0"]
+	require.True(t, ok)
+	assert.Equal(t, "Apple GPU", g0.Name)
+	// macmon reports usage fraction 0..1; expect percent conversion.
+	assert.InDelta(t, 1.3633, g0.Usage, 0.05)
+	// power includes gpu_power + gpu_ram_power
+	assert.InDelta(t, 0.011824, g0.Power, 0.0005)
+	assert.InDelta(t, 29.445, g0.Temperature, 0.01)
+	assert.Equal(t, 1.0, g0.Count)
+}

internal/hub/heartbeat/heartbeat.go

@@ -0,0 +1,303 @@
+// Package heartbeat sends periodic outbound pings to an external monitoring
+// endpoint (e.g. BetterStack, Uptime Kuma, Healthchecks.io) so operators can
+// monitor Beszel without exposing it to the internet.
+package heartbeat
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/henrygd/beszel"
+	"github.com/pocketbase/pocketbase/core"
+)
+
+// Default values for heartbeat configuration.
+const (
+	defaultInterval = 60 // seconds
+	httpTimeout     = 10 * time.Second
+)
+
+// Payload is the JSON body sent with each heartbeat request.
+type Payload struct {
+	// Status is "ok" when all non-paused systems are up, "warn" when alerts
+	// are triggered but no systems are down, and "error" when any system is down.
+	Status    string         `json:"status"`
+	Timestamp string         `json:"timestamp"`
+	Msg       string         `json:"msg"`
+	Systems   SystemsSummary `json:"systems"`
+	Down      []SystemInfo   `json:"down_systems,omitempty"`
+	Alerts    []AlertInfo    `json:"triggered_alerts,omitempty"`
+	Version   string         `json:"beszel_version"`
+}
+
+// SystemsSummary contains counts of systems by status.
+type SystemsSummary struct {
+	Total   int `json:"total"`
+	Up      int `json:"up"`
+	Down    int `json:"down"`
+	Paused  int `json:"paused"`
+	Pending int `json:"pending"`
+}
+
+// SystemInfo identifies a system that is currently down.
+type SystemInfo struct {
+	ID   string `json:"id" db:"id"`
+	Name string `json:"name" db:"name"`
+	Host string `json:"host" db:"host"`
+}
+
+// AlertInfo describes a currently triggered alert.
+type AlertInfo struct {
+	SystemID   string  `json:"system_id"`
+	SystemName string  `json:"system_name"`
+	AlertName  string  `json:"alert_name"`
+	Threshold  float64 `json:"threshold"`
+}
+
+// Config holds heartbeat settings read from environment variables.
+type Config struct {
+	URL      string // endpoint to ping
+	Interval int    // seconds between pings
+	Method   string // HTTP method (GET or POST, default POST)
+}
+
+// Heartbeat manages the periodic outbound health check.
+type Heartbeat struct {
+	app    core.App
+	config Config
+	client *http.Client
+}
+
+// New creates a Heartbeat if configuration is present.
+// Returns nil if HEARTBEAT_URL is not set (feature disabled).
+func New(app core.App, getEnv func(string) (string, bool)) *Heartbeat {
+	url, _ := getEnv("HEARTBEAT_URL")
+	url = strings.TrimSpace(url)
+	if app == nil || url == "" {
+		return nil
+	}
+
+	interval := defaultInterval
+	if v, ok := getEnv("HEARTBEAT_INTERVAL"); ok {
+		if parsed, err := strconv.Atoi(v); err == nil && parsed > 0 {
+			interval = parsed
+		}
+	}
+
+	method := http.MethodPost
+	if v, ok := getEnv("HEARTBEAT_METHOD"); ok {
+		v = strings.ToUpper(strings.TrimSpace(v))
+		if v == http.MethodGet || v == http.MethodHead {
+			method = v
+		}
+	}
+
+	return &Heartbeat{
+		app: app,
+		config: Config{
+			URL:      url,
+			Interval: interval,
+			Method:   method,
+		},
+		client: &http.Client{Timeout: httpTimeout},
+	}
+}
+
+// Start begins the heartbeat loop. It blocks and should be called in a goroutine.
+// The loop runs until the provided stop channel is closed.
+func (hb *Heartbeat) Start(stop <-chan struct{}) {
+	sanitizedURL := sanitizeHeartbeatURL(hb.config.URL)
+	hb.app.Logger().Info("Heartbeat enabled",
+		"url", sanitizedURL,
+		"interval", fmt.Sprintf("%ds", hb.config.Interval),
+		"method", hb.config.Method,
+	)
+
+	// Send an initial heartbeat immediately on startup.
+	hb.send()
+
+	ticker := time.NewTicker(time.Duration(hb.config.Interval) * time.Second)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-stop:
+			return
+		case <-ticker.C:
+			hb.send()
+		}
+	}
+}
+
+// Send performs a single heartbeat ping. Exposed for the test-heartbeat API endpoint.
+func (hb *Heartbeat) Send() error {
+	return hb.send()
+}
+
+// GetConfig returns the current heartbeat configuration.
+func (hb *Heartbeat) GetConfig() Config {
+	return hb.config
+}
+
+func (hb *Heartbeat) send() error {
+	var req *http.Request
+	var err error
+	method := normalizeMethod(hb.config.Method)
+
+	if method == http.MethodGet || method == http.MethodHead {
+		req, err = http.NewRequest(method, hb.config.URL, nil)
+	} else {
+		payload, payloadErr := hb.buildPayload()
+		if payloadErr != nil {
+			hb.app.Logger().Error("Heartbeat: failed to build payload", "err", payloadErr)
+			return payloadErr
+		}
+
+		body, jsonErr := json.Marshal(payload)
+		if jsonErr != nil {
+			hb.app.Logger().Error("Heartbeat: failed to marshal payload", "err", jsonErr)
+			return jsonErr
+		}
+		req, err = http.NewRequest(http.MethodPost, hb.config.URL, bytes.NewReader(body))
+		if err == nil {
+			req.Header.Set("Content-Type", "application/json")
+		}
+	}
+
+	if err != nil {
+		hb.app.Logger().Error("Heartbeat: failed to create request", "err", err)
+		return err
+	}
+
+	req.Header.Set("User-Agent", "Beszel-Heartbeat")
+
+	resp, err := hb.client.Do(req)
+	if err != nil {
+		hb.app.Logger().Error("Heartbeat: request failed", "url", sanitizeHeartbeatURL(hb.config.URL), "err", err)
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		hb.app.Logger().Warn("Heartbeat: non-success response",
+			"url", sanitizeHeartbeatURL(hb.config.URL),
+			"status", resp.StatusCode,
+		)
+		return fmt.Errorf("heartbeat endpoint returned status %d", resp.StatusCode)
+	}
+
+	return nil
+}
+
+func (hb *Heartbeat) buildPayload() (*Payload, error) {
+	db := hb.app.DB()
+
+	// Count systems by status.
+	var systemCounts []struct {
+		Status string `db:"status"`
+		Count  int    `db:"cnt"`
+	}
+	err := db.NewQuery("SELECT status, COUNT(*) as cnt FROM systems GROUP BY status").All(&systemCounts)
+	if err != nil {
+		return nil, fmt.Errorf("query system counts: %w", err)
+	}
+
+	summary := SystemsSummary{}
+	for _, sc := range systemCounts {
+		switch sc.Status {
+		case "up":
+			summary.Up = sc.Count
+		case "down":
+			summary.Down = sc.Count
+		case "paused":
+			summary.Paused = sc.Count
+		case "pending":
+			summary.Pending = sc.Count
+		}
+		summary.Total += sc.Count
+	}
+
+	// Get names of down systems.
+	var downSystems []SystemInfo
+	if summary.Down > 0 {
+		err = db.NewQuery("SELECT id, name, host FROM systems WHERE status = 'down'").All(&downSystems)
+		if err != nil {
+			return nil, fmt.Errorf("query down systems: %w", err)
+		}
+	}
+
+	// Get triggered alerts with system names.
+	var triggeredAlerts []struct {
+		SystemID   string  `db:"system"`
+		SystemName string  `db:"system_name"`
+		AlertName  string  `db:"name"`
+		Value      float64 `db:"value"`
+	}
+	err = db.NewQuery(`
+		SELECT a.system, s.name as system_name, a.name, a.value
+		FROM alerts a
+		JOIN systems s ON a.system = s.id
+		WHERE a.triggered = true
+	`).All(&triggeredAlerts)
+	if err != nil {
+		// Non-fatal: alerts info is supplementary.
+		triggeredAlerts = nil
+	}
+
+	alerts := make([]AlertInfo, 0, len(triggeredAlerts))
+	for _, ta := range triggeredAlerts {
+		alerts = append(alerts, AlertInfo{
+			SystemID:   ta.SystemID,
+			SystemName: ta.SystemName,
+			AlertName:  ta.AlertName,
+			Threshold:  ta.Value,
+		})
+	}
+
+	// Determine overall status.
+	status := "ok"
+	msg := "All systems operational"
+	if summary.Down > 0 {
+		status = "error"
+		names := make([]string, len(downSystems))
+		for i, ds := range downSystems {
+			names[i] = ds.Name
+		}
+		msg = fmt.Sprintf("%d system(s) down: %s", summary.Down, strings.Join(names, ", "))
+	} else if len(alerts) > 0 {
+		status = "warn"
+		msg = fmt.Sprintf("%d alert(s) triggered", len(alerts))
+	}
+
+	return &Payload{
+		Status:    status,
+		Timestamp: time.Now().UTC().Format(time.RFC3339),
+		Msg:       msg,
+		Systems:   summary,
+		Down:      downSystems,
+		Alerts:    alerts,
+		Version:   beszel.Version,
+	}, nil
+}
+
+func normalizeMethod(method string) string {
+	upper := strings.ToUpper(strings.TrimSpace(method))
+	if upper == http.MethodGet || upper == http.MethodHead || upper == http.MethodPost {
+		return upper
+	}
+	return http.MethodPost
+}
+
+func sanitizeHeartbeatURL(rawURL string) string {
+	parsed, err := url.Parse(strings.TrimSpace(rawURL))
+	if err != nil || parsed.Scheme == "" || parsed.Host == "" {
+		return "<invalid-url>"
+	}
+	return parsed.Scheme + "://" + parsed.Host
+}

internal/hub/heartbeat/heartbeat_test.go

@@ -0,0 +1,258 @@
+//go:build testing
+// +build testing
+
+package heartbeat_test
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/henrygd/beszel/internal/hub/heartbeat"
+	beszeltests "github.com/henrygd/beszel/internal/tests"
+	"github.com/pocketbase/pocketbase/core"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNew(t *testing.T) {
+	t.Run("returns nil when app is missing", func(t *testing.T) {
+		hb := heartbeat.New(nil, envGetter(map[string]string{
+			"HEARTBEAT_URL": "https://heartbeat.example.com/ping",
+		}))
+		assert.Nil(t, hb)
+	})
+
+	t.Run("returns nil when URL is missing", func(t *testing.T) {
+		app := newTestHub(t)
+		hb := heartbeat.New(app.App, func(string) (string, bool) {
+			return "", false
+		})
+		assert.Nil(t, hb)
+	})
+
+	t.Run("parses and normalizes config values", func(t *testing.T) {
+		app := newTestHub(t)
+		env := map[string]string{
+			"HEARTBEAT_URL":      "  https://heartbeat.example.com/ping  ",
+			"HEARTBEAT_INTERVAL": "90",
+			"HEARTBEAT_METHOD":   "head",
+		}
+		getEnv := func(key string) (string, bool) {
+			v, ok := env[key]
+			return v, ok
+		}
+
+		hb := heartbeat.New(app.App, getEnv)
+		require.NotNil(t, hb)
+		cfg := hb.GetConfig()
+		assert.Equal(t, "https://heartbeat.example.com/ping", cfg.URL)
+		assert.Equal(t, 90, cfg.Interval)
+		assert.Equal(t, http.MethodHead, cfg.Method)
+	})
+}
+
+func TestSendGETDoesNotRequireAppOrDB(t *testing.T) {
+	app := newTestHub(t)
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, http.MethodGet, r.Method)
+		assert.Equal(t, "Beszel-Heartbeat", r.Header.Get("User-Agent"))
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer server.Close()
+
+	hb := heartbeat.New(app.App, envGetter(map[string]string{
+		"HEARTBEAT_URL":    server.URL,
+		"HEARTBEAT_METHOD": "GET",
+	}))
+	require.NotNil(t, hb)
+
+	require.NoError(t, hb.Send())
+}
+
+func TestSendReturnsErrorOnHTTPFailureStatus(t *testing.T) {
+	app := newTestHub(t)
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+	}))
+	defer server.Close()
+
+	hb := heartbeat.New(app.App, envGetter(map[string]string{
+		"HEARTBEAT_URL":    server.URL,
+		"HEARTBEAT_METHOD": "GET",
+	}))
+	require.NotNil(t, hb)
+
+	err := hb.Send()
+	require.Error(t, err)
+	assert.ErrorContains(t, err, "heartbeat endpoint returned status 500")
+}
+
+func TestSendPOSTBuildsExpectedStatuses(t *testing.T) {
+	tests := []struct {
+		name           string
+		setup          func(t *testing.T, app *beszeltests.TestHub, user *core.Record)
+		expectStatus   string
+		expectMsgPart  string
+		expectDown     int
+		expectAlerts   int
+		expectTotal    int
+		expectUp       int
+		expectPaused   int
+		expectPending  int
+		expectDownSumm int
+	}{
+		{
+			name: "error when at least one system is down",
+			setup: func(t *testing.T, app *beszeltests.TestHub, user *core.Record) {
+				downSystem := createTestSystem(t, app, user.Id, "db-1", "10.0.0.1", "down")
+				_ = createTestSystem(t, app, user.Id, "web-1", "10.0.0.2", "up")
+				createTriggeredAlert(t, app, user.Id, downSystem.Id, "CPU", 95)
+			},
+			expectStatus:   "error",
+			expectMsgPart:  "1 system(s) down",
+			expectDown:     1,
+			expectAlerts:   1,
+			expectTotal:    2,
+			expectUp:       1,
+			expectDownSumm: 1,
+		},
+		{
+			name: "warn when only alerts are triggered",
+			setup: func(t *testing.T, app *beszeltests.TestHub, user *core.Record) {
+				system := createTestSystem(t, app, user.Id, "api-1", "10.1.0.1", "up")
+				createTriggeredAlert(t, app, user.Id, system.Id, "CPU", 90)
+			},
+			expectStatus:   "warn",
+			expectMsgPart:  "1 alert(s) triggered",
+			expectDown:     0,
+			expectAlerts:   1,
+			expectTotal:    1,
+			expectUp:       1,
+			expectDownSumm: 0,
+		},
+		{
+			name: "ok when no down systems and no alerts",
+			setup: func(t *testing.T, app *beszeltests.TestHub, user *core.Record) {
+				_ = createTestSystem(t, app, user.Id, "node-1", "10.2.0.1", "up")
+				_ = createTestSystem(t, app, user.Id, "node-2", "10.2.0.2", "paused")
+				_ = createTestSystem(t, app, user.Id, "node-3", "10.2.0.3", "pending")
+			},
+			expectStatus:   "ok",
+			expectMsgPart:  "All systems operational",
+			expectDown:     0,
+			expectAlerts:   0,
+			expectTotal:    3,
+			expectUp:       1,
+			expectPaused:   1,
+			expectPending:  1,
+			expectDownSumm: 0,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			app := newTestHub(t)
+			user := createTestUser(t, app)
+			tt.setup(t, app, user)
+
+			type requestCapture struct {
+				method      string
+				userAgent   string
+				contentType string
+				payload     heartbeat.Payload
+			}
+
+			captured := make(chan requestCapture, 1)
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				defer r.Body.Close()
+				body, err := io.ReadAll(r.Body)
+				require.NoError(t, err)
+
+				var payload heartbeat.Payload
+				require.NoError(t, json.Unmarshal(body, &payload))
+				captured <- requestCapture{
+					method:      r.Method,
+					userAgent:   r.Header.Get("User-Agent"),
+					contentType: r.Header.Get("Content-Type"),
+					payload:     payload,
+				}
+				w.WriteHeader(http.StatusNoContent)
+			}))
+			defer server.Close()
+
+			hb := heartbeat.New(app.App, envGetter(map[string]string{
+				"HEARTBEAT_URL":    server.URL,
+				"HEARTBEAT_METHOD": "POST",
+			}))
+			require.NotNil(t, hb)
+			require.NoError(t, hb.Send())
+
+			req := <-captured
+			assert.Equal(t, http.MethodPost, req.method)
+			assert.Equal(t, "Beszel-Heartbeat", req.userAgent)
+			assert.Equal(t, "application/json", req.contentType)
+
+			assert.Equal(t, tt.expectStatus, req.payload.Status)
+			assert.Contains(t, req.payload.Msg, tt.expectMsgPart)
+			assert.Equal(t, tt.expectDown, len(req.payload.Down))
+			assert.Equal(t, tt.expectAlerts, len(req.payload.Alerts))
+			assert.Equal(t, tt.expectTotal, req.payload.Systems.Total)
+			assert.Equal(t, tt.expectUp, req.payload.Systems.Up)
+			assert.Equal(t, tt.expectDownSumm, req.payload.Systems.Down)
+			assert.Equal(t, tt.expectPaused, req.payload.Systems.Paused)
+			assert.Equal(t, tt.expectPending, req.payload.Systems.Pending)
+		})
+	}
+}
+
+func newTestHub(t *testing.T) *beszeltests.TestHub {
+	t.Helper()
+	app, err := beszeltests.NewTestHub(t.TempDir())
+	require.NoError(t, err)
+	t.Cleanup(app.Cleanup)
+	return app
+}
+
+func createTestUser(t *testing.T, app *beszeltests.TestHub) *core.Record {
+	t.Helper()
+	user, err := beszeltests.CreateUser(app.App, "admin@example.com", "password123")
+	require.NoError(t, err)
+	return user
+}
+
+func createTestSystem(t *testing.T, app *beszeltests.TestHub, userID, name, host, status string) *core.Record {
+	t.Helper()
+	system, err := beszeltests.CreateRecord(app.App, "systems", map[string]any{
+		"name":   name,
+		"host":   host,
+		"port":   "45876",
+		"users":  []string{userID},
+		"status": status,
+	})
+	require.NoError(t, err)
+	return system
+}
+
+func createTriggeredAlert(t *testing.T, app *beszeltests.TestHub, userID, systemID, name string, threshold float64) *core.Record {
+	t.Helper()
+	alert, err := beszeltests.CreateRecord(app.App, "alerts", map[string]any{
+		"name":      name,
+		"system":    systemID,
+		"user":      userID,
+		"value":     threshold,
+		"min":       0,
+		"triggered": true,
+	})
+	require.NoError(t, err)
+	return alert
+}
+
+func envGetter(values map[string]string) func(string) (string, bool) {
+	return func(key string) (string, bool) {
+		v, ok := values[key]
+		return v, ok
+	}
+}

internal/hub/hub.go

@@ -15,6 +15,7 @@ import (
 	"github.com/henrygd/beszel"
 	"github.com/henrygd/beszel/internal/alerts"
 	"github.com/henrygd/beszel/internal/hub/config"
+	"github.com/henrygd/beszel/internal/hub/heartbeat"
 	"github.com/henrygd/beszel/internal/hub/systems"
 	"github.com/henrygd/beszel/internal/records"
 	"github.com/henrygd/beszel/internal/users"
@@ -33,6 +34,8 @@ type Hub struct {
 	um     *users.UserManager
 	rm     *records.RecordManager
 	sm     *systems.SystemManager
+	hb     *heartbeat.Heartbeat
+	hbStop chan struct{}
 	pubKey string
 	signer ssh.Signer
 	appURL string
@@ -48,6 +51,10 @@ func NewHub(app core.App) *Hub {
 	hub.rm = records.NewRecordManager(hub)
 	hub.sm = systems.NewSystemManager(hub)
 	hub.appURL, _ = GetEnv("APP_URL")
+	hub.hb = heartbeat.New(app, GetEnv)
+	if hub.hb != nil {
+		hub.hbStop = make(chan struct{})
+	}
 	return hub
 }
 
@@ -88,6 +95,10 @@ func (h *Hub) StartHub() error {
 		if err := h.sm.Initialize(); err != nil {
 			return err
 		}
+		// start heartbeat if configured
+		if h.hb != nil {
+			go h.hb.Start(h.hbStop)
+		}
 		return e.Next()
 	})
 
@@ -287,6 +298,9 @@ func (h *Hub) registerApiRoutes(se *core.ServeEvent) error {
 	})
 	// send test notification
 	apiAuth.POST("/test-notification", h.SendTestNotification)
+	// heartbeat status and test
+	apiAuth.GET("/heartbeat-status", h.getHeartbeatStatus)
+	apiAuth.POST("/test-heartbeat", h.testHeartbeat)
 	// get config.yml content
 	apiAuth.GET("/config-yaml", config.GetYamlConfig)
 	// handle agent websocket connection
@@ -403,6 +417,42 @@ func (h *Hub) getUniversalToken(e *core.RequestEvent) error {
 	return e.JSON(http.StatusOK, response)
 }
 
+// getHeartbeatStatus returns current heartbeat configuration and whether it's enabled
+func (h *Hub) getHeartbeatStatus(e *core.RequestEvent) error {
+	if e.Auth.GetString("role") != "admin" {
+		return e.ForbiddenError("Requires admin role", nil)
+	}
+	if h.hb == nil {
+		return e.JSON(http.StatusOK, map[string]any{
+			"enabled": false,
+			"msg":     "Set HEARTBEAT_URL to enable outbound heartbeat monitoring",
+		})
+	}
+	cfg := h.hb.GetConfig()
+	return e.JSON(http.StatusOK, map[string]any{
+		"enabled":  true,
+		"url":      cfg.URL,
+		"interval": cfg.Interval,
+		"method":   cfg.Method,
+	})
+}
+
+// testHeartbeat triggers a single heartbeat ping and returns the result
+func (h *Hub) testHeartbeat(e *core.RequestEvent) error {
+	if e.Auth.GetString("role") != "admin" {
+		return e.ForbiddenError("Requires admin role", nil)
+	}
+	if h.hb == nil {
+		return e.JSON(http.StatusOK, map[string]any{
+			"err": "Heartbeat not configured. Set HEARTBEAT_URL environment variable.",
+		})
+	}
+	if err := h.hb.Send(); err != nil {
+		return e.JSON(http.StatusOK, map[string]any{"err": err.Error()})
+	}
+	return e.JSON(http.StatusOK, map[string]any{"err": false})
+}
+
 // containerRequestHandler handles both container logs and info requests
 func (h *Hub) containerRequestHandler(e *core.RequestEvent, fetchFunc func(*systems.System, string) (string, error), responseKey string) error {
 	systemID := e.Request.URL.Query().Get("system")

internal/hub/hub_test.go

@@ -362,6 +362,58 @@ func TestApiRoutesAuthentication(t *testing.T) {
 			ExpectedContent: []string{"test-system"},
 			TestAppFactory:  testAppFactory,
 		},
+		{
+			Name:            "GET /heartbeat-status - no auth should fail",
+			Method:          http.MethodGet,
+			URL:             "/api/beszel/heartbeat-status",
+			ExpectedStatus:  401,
+			ExpectedContent: []string{"requires valid"},
+			TestAppFactory:  testAppFactory,
+		},
+		{
+			Name:   "GET /heartbeat-status - with user auth should fail",
+			Method: http.MethodGet,
+			URL:    "/api/beszel/heartbeat-status",
+			Headers: map[string]string{
+				"Authorization": userToken,
+			},
+			ExpectedStatus:  403,
+			ExpectedContent: []string{"Requires admin role"},
+			TestAppFactory:  testAppFactory,
+		},
+		{
+			Name:   "GET /heartbeat-status - with admin auth should succeed",
+			Method: http.MethodGet,
+			URL:    "/api/beszel/heartbeat-status",
+			Headers: map[string]string{
+				"Authorization": adminUserToken,
+			},
+			ExpectedStatus:  200,
+			ExpectedContent: []string{`"enabled":false`},
+			TestAppFactory:  testAppFactory,
+		},
+		{
+			Name:   "POST /test-heartbeat - with user auth should fail",
+			Method: http.MethodPost,
+			URL:    "/api/beszel/test-heartbeat",
+			Headers: map[string]string{
+				"Authorization": userToken,
+			},
+			ExpectedStatus:  403,
+			ExpectedContent: []string{"Requires admin role"},
+			TestAppFactory:  testAppFactory,
+		},
+		{
+			Name:   "POST /test-heartbeat - with admin auth should report disabled state",
+			Method: http.MethodPost,
+			URL:    "/api/beszel/test-heartbeat",
+			Headers: map[string]string{
+				"Authorization": adminUserToken,
+			},
+			ExpectedStatus:  200,
+			ExpectedContent: []string{"Heartbeat not configured"},
+			TestAppFactory:  testAppFactory,
+		},
 		{
 			Name:            "GET /universal-token - no auth should fail",
 			Method:          http.MethodGet,

internal/site/src/components/routes/settings/heartbeat.tsx

@@ -0,0 +1,205 @@
+import { t } from "@lingui/core/macro"
+import { Trans } from "@lingui/react/macro"
+import { redirectPage } from "@nanostores/router"
+import clsx from "clsx"
+import { LoaderCircleIcon, SendIcon } from "lucide-react"
+import { useEffect, useState } from "react"
+import { $router } from "@/components/router"
+import { Badge } from "@/components/ui/badge"
+import { Button } from "@/components/ui/button"
+import { Separator } from "@/components/ui/separator"
+import { toast } from "@/components/ui/use-toast"
+import { isAdmin, pb } from "@/lib/api"
+
+interface HeartbeatStatus {
+	enabled: boolean
+	url?: string
+	interval?: number
+	method?: string
+	msg?: string
+}
+
+export default function HeartbeatSettings() {
+	const [status, setStatus] = useState<HeartbeatStatus | null>(null)
+	const [isLoading, setIsLoading] = useState(true)
+	const [isTesting, setIsTesting] = useState(false)
+
+	if (!isAdmin()) {
+		redirectPage($router, "settings", { name: "general" })
+	}
+
+	useEffect(() => {
+		fetchStatus()
+	}, [])
+
+	async function fetchStatus() {
+		try {
+			setIsLoading(true)
+			const res = await pb.send<HeartbeatStatus>("/api/beszel/heartbeat-status", {})
+			setStatus(res)
+		} catch (error: any) {
+			toast({
+				title: t`Error`,
+				description: error.message,
+				variant: "destructive",
+			})
+		} finally {
+			setIsLoading(false)
+		}
+	}
+
+	async function sendTestHeartbeat() {
+		setIsTesting(true)
+		try {
+			const res = await pb.send<{ err: string | false }>("/api/beszel/test-heartbeat", {
+				method: "POST",
+			})
+			if ("err" in res && !res.err) {
+				toast({
+					title: t`Heartbeat sent successfully`,
+					description: t`Check your monitoring service`,
+				})
+			} else {
+				toast({
+					title: t`Error`,
+					description: (res.err as string) ?? t`Failed to send heartbeat`,
+					variant: "destructive",
+				})
+			}
+		} catch (error: any) {
+			toast({
+				title: t`Error`,
+				description: error.message,
+				variant: "destructive",
+			})
+		} finally {
+			setIsTesting(false)
+		}
+	}
+
+	const TestIcon = isTesting ? LoaderCircleIcon : SendIcon
+
+	return (
+		<div>
+			<div>
+				<h3 className="text-xl font-medium mb-2">
+					<Trans>Heartbeat Monitoring</Trans>
+				</h3>
+				<p className="text-sm text-muted-foreground leading-relaxed">
+					<Trans>
+						Send periodic outbound pings to an external monitoring service so you can monitor Beszel without exposing it
+						to the internet.
+					</Trans>
+				</p>
+			</div>
+			<Separator className="my-4" />
+
+			{isLoading ? (
+				<div className="flex items-center gap-2 text-muted-foreground py-4">
+					<LoaderCircleIcon className="h-4 w-4 animate-spin" />
+					<Trans>Loading heartbeat status...</Trans>
+				</div>
+			) : status?.enabled ? (
+				<div className="space-y-5">
+					<div className="flex items-center gap-2">
+						<Badge variant="success">
+							<Trans>Active</Trans>
+						</Badge>
+					</div>
+					<div className="grid gap-4 sm:grid-cols-2">
+						<ConfigItem label={t`Endpoint URL`} value={status.url ?? ""} mono />
+						<ConfigItem label={t`Interval`} value={`${status.interval}s`} />
+						<ConfigItem label={t`HTTP Method`} value={status.method ?? "POST"} />
+					</div>
+
+					<Separator />
+
+					<div>
+						<h4 className="text-base font-medium mb-1">
+							<Trans>Test heartbeat</Trans>
+						</h4>
+						<p className="text-sm text-muted-foreground leading-relaxed mb-3">
+							<Trans>Send a single heartbeat ping to verify your endpoint is working.</Trans>
+						</p>
+						<Button
+							type="button"
+							variant="outline"
+							className="flex items-center gap-1.5"
+							onClick={sendTestHeartbeat}
+							disabled={isTesting}
+						>
+							<TestIcon className={clsx("h-4 w-4", isTesting && "animate-spin")} />
+							<Trans>Send test heartbeat</Trans>
+						</Button>
+					</div>
+
+					<Separator />
+
+					<div>
+						<h4 className="text-base font-medium mb-2">
+							<Trans>Payload format</Trans>
+						</h4>
+						<p className="text-sm text-muted-foreground leading-relaxed mb-2">
+							<Trans>
+								When using POST, each heartbeat includes a JSON payload with system status summary, list of down
+								systems, and triggered alerts.
+							</Trans>
+						</p>
+						<p className="text-sm text-muted-foreground leading-relaxed">
+							<Trans>
+								The overall status is <code className="bg-muted rounded-sm px-1 text-primary">ok</code> when all systems
+								are up, <code className="bg-muted rounded-sm px-1 text-primary">warn</code> when alerts are triggered,
+								and <code className="bg-muted rounded-sm px-1 text-primary">error</code> when any system is down.
+							</Trans>
+						</p>
+					</div>
+				</div>
+			) : (
+				<div className="grid gap-4">
+					<div>
+						<p className="text-sm text-muted-foreground leading-relaxed mb-3">
+							<Trans>Set the following environment variables on your Beszel hub to enable heartbeat monitoring:</Trans>
+						</p>
+						<div className="grid gap-2.5">
+							<EnvVarItem
+								name="HEARTBEAT_URL"
+								description={t`Endpoint URL to ping (required)`}
+								example="https://uptime.betterstack.com/api/v1/heartbeat/xxxx"
+							/>
+							<EnvVarItem name="HEARTBEAT_INTERVAL" description={t`Seconds between pings (default: 60)`} example="60" />
+							<EnvVarItem
+								name="HEARTBEAT_METHOD"
+								description={t`HTTP method: POST, GET, or HEAD (default: POST)`}
+								example="POST"
+							/>
+						</div>
+					</div>
+					<p className="text-sm text-muted-foreground leading-relaxed">
+						<Trans>After setting the environment variables, restart your Beszel hub for changes to take effect.</Trans>
+					</p>
+				</div>
+			)}
+		</div>
+	)
+}
+
+function ConfigItem({ label, value, mono }: { label: string; value: string; mono?: boolean }) {
+	return (
+		<div>
+			<p className="text-sm font-medium mb-0.5">{label}</p>
+			<p className={clsx("text-sm text-muted-foreground break-all", mono && "font-mono")}>{value}</p>
+		</div>
+	)
+}
+
+function EnvVarItem({ name, description, example }: { name: string; description: string; example: string }) {
+	return (
+		<div className="bg-muted/50 rounded-md px-3 py-2 grid gap-1.5">
+			<code className="text-sm font-mono text-primary font-medium leading-tight">{name}</code>
+			<p className="text-sm text-muted-foreground">{description}</p>
+			<p className="text-xs text-muted-foreground">
+				<Trans>Example:</Trans> <code className="font-mono">{example}</code>
+			</p>
+		</div>
+	)
+}

internal/site/src/components/routes/settings/layout.tsx

@@ -2,7 +2,14 @@ import { t } from "@lingui/core/macro"
 import { Trans, useLingui } from "@lingui/react/macro"
 import { useStore } from "@nanostores/react"
 import { getPagePath, redirectPage } from "@nanostores/router"
-import { AlertOctagonIcon, BellIcon, FileSlidersIcon, FingerprintIcon, SettingsIcon } from "lucide-react"
+import {
+	AlertOctagonIcon,
+	BellIcon,
+	FileSlidersIcon,
+	FingerprintIcon,
+	HeartPulseIcon,
+	SettingsIcon,
+} from "lucide-react"
 import { lazy, useEffect } from "react"
 import { $router } from "@/components/router.tsx"
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card.tsx"
@@ -18,12 +25,14 @@ const notificationsSettingsImport = () => import("./notifications.tsx")
 const configYamlSettingsImport = () => import("./config-yaml.tsx")
 const fingerprintsSettingsImport = () => import("./tokens-fingerprints.tsx")
 const alertsHistoryDataTableSettingsImport = () => import("./alerts-history-data-table.tsx")
+const heartbeatSettingsImport = () => import("./heartbeat.tsx")
 
 const GeneralSettings = lazy(generalSettingsImport)
 const NotificationsSettings = lazy(notificationsSettingsImport)
 const ConfigYamlSettings = lazy(configYamlSettingsImport)
 const FingerprintsSettings = lazy(fingerprintsSettingsImport)
 const AlertsHistoryDataTableSettings = lazy(alertsHistoryDataTableSettingsImport)
+const HeartbeatSettings = lazy(heartbeatSettingsImport)
 
 export async function saveSettings(newSettings: Partial<UserSettings>) {
 	try {
@@ -88,6 +97,13 @@ export default function SettingsLayout() {
 			admin: true,
 			preload: configYamlSettingsImport,
 		},
+		{
+			title: t`Heartbeat`,
+			href: getPagePath($router, "settings", { name: "heartbeat" }),
+			icon: HeartPulseIcon,
+			admin: true,
+			preload: heartbeatSettingsImport,
+		},
 	]
 
 	const page = useStore($router)
@@ -141,5 +157,7 @@ function SettingsContent({ name }: { name: string }) {
 			return <FingerprintsSettings />
 		case "alert-history":
 			return <AlertsHistoryDataTableSettings />
+		case "heartbeat":
+			return <HeartbeatSettings />
 	}
 }

supplemental/CHANGELOG.md

@@ -1,3 +1,9 @@
+## Unreleased
+
+- Add outbound heartbeat monitoring to external services (BetterStack, Uptime Kuma, Healthchecks.io, etc.) with system status summary payload. Configured via `BESZEL_HUB_HEARTBEAT_URL`, `BESZEL_HUB_HEARTBEAT_INTERVAL`, and `BESZEL_HUB_HEARTBEAT_METHOD` environment variables.
+
+- Add Heartbeat settings page to the admin UI with status display, configuration reference, and test button.
+
 ## 0.18.3
 
 - Add experimental sysfs AMD GPU collector. (#737, #1569)