diff --git a/.gitignore b/.gitignore
index cfaad76..1b17cb7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 *.pem
+app-gateway-go
diff --git a/main.go b/main.go
index 76f8226..63be15f 100644
--- a/main.go
+++ b/main.go
@@ -61,6 +61,7 @@ const (
 	gatewayVerboseEnvironmentVariable        = "VERBOSE"
 	logSecretsEnvironmentVariable            = "LOG_SECRETS"
 	targetRewritesVariables                  = "TARGET_REWRITES"
+	prometheusConfigVariable                 = "PROMETHEUS_CONFIG"
 )
 
 var versionFlag = flag.Bool("version", false, "print name and version to stdout")
@@ -198,8 +199,6 @@ func main() {
 	debugResponse := getBoolEnv(gatewayDebugEnvironmentVariable, false)
 	verbose := getBoolEnv(gatewayVerboseEnvironmentVariable, false)
 
-	monitoringServiceName := getStringEnv(monitoringServiceNameEnvironmentVariable, defaultMonitoringServiceName)
-
 	configID := uint8(getUintEnv(configurationIdEnvironmentVariable, 0))
 	config, err := ohttp.NewConfigFromSeed(configID, hpke.KEM_X25519_KYBER768_DRAFT00, hpke.KDF_HKDF_SHA256, hpke.AEAD_AES128GCM, seed)
 	if err != nil {
@@ -263,23 +262,40 @@ func main() {
 	}
 
 	// Configure metrics
-	metricsHost := os.Getenv(statsdHostVariable)
-	metricsPort := os.Getenv(statsdPortVariable)
-	metricsTimeout, err := strconv.ParseInt(os.Getenv(statsdTimeoutVariable), 10, 64)
-	if err != nil {
-		log.Printf("Failed parsing metrics timeout: %s", err)
-		metricsTimeout = 100
-	}
-	client, err := createStatsDClient(metricsHost, metricsPort, int(metricsTimeout))
-	if err != nil {
-		log.Fatalf("Failed to create statsd client: %s", err)
-	}
-	defer client.Close()
+	var metricsFactory MetricsFactory
+
+	if prometheusConfigJSON := os.Getenv(prometheusConfigVariable); prometheusConfigJSON != "" {
+		log.Printf("prometheus config: %s", prometheusConfigJSON)
+		var prometheusConfig PrometheusConfig
+		if err := json.Unmarshal([]byte(prometheusConfigJSON), &prometheusConfig); err != nil {
+			log.Fatalf("Failed to parse Prometheus config: %s", err)
+		}
+
+		metricsFactory, err = NewPrometheusMetricsFactory(prometheusConfig)
+		if err != nil {
+			log.Fatalf("Failed to configure Prometheus metrics: %s", err)
+		}
+	} else {
+		// Default to StatsD metrics
+		monitoringServiceName := getStringEnv(monitoringServiceNameEnvironmentVariable, defaultMonitoringServiceName)
+		metricsHost := os.Getenv(statsdHostVariable)
+		metricsPort := os.Getenv(statsdPortVariable)
+		metricsTimeout, err := strconv.ParseInt(getStringEnv(statsdTimeoutVariable, "100"), 10, 64)
+		if err != nil {
+			log.Fatalf("Failed parsing metrics timeout: %s", err)
+			metricsTimeout = 100
+		}
+		client, err := createStatsDClient(metricsHost, metricsPort, int(metricsTimeout))
+		if err != nil {
+			log.Fatalf("Failed to create statsd client: %s", err)
+		}
+		defer client.Close()
 
-	metricsFactory := &StatsDMetricsFactory{
-		serviceName: monitoringServiceName,
-		metricsName: "ohttp_gateway_duration",
-		client:      client,
+		metricsFactory = &StatsDMetricsFactory{
+			serviceName: monitoringServiceName,
+			metricsName: "ohttp_gateway_duration",
+			client:      client,
+		}
 	}
 
 	// Load endpoint configuration defaults
diff --git a/prometheus_metrics.go b/prometheus_metrics.go
new file mode 100644
index 0000000..3d103e3
--- /dev/null
+++ b/prometheus_metrics.go
@@ -0,0 +1,88 @@
+// Copyright (c) 2024 Cloudflare, Inc. All rights reserved.
+// SPDX-License-Identifier: BSD-3-Clause
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	//"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+type PrometheusConfig struct {
+	Host       string
+	Port       string
+	ScrapePath string
+	MetricName string
+}
+
+type PrometheusMetrics struct {
+	startedAt time.Time
+	histogram prometheus.ObserverVec
+}
+
+func (p *PrometheusMetrics) Fire(result string) {
+	observer := p.histogram.With(prometheus.Labels{"method": "unknown", "status": "unknown", "result": result})
+	p.observe(observer)
+}
+
+func (p *PrometheusMetrics) ResponseStatus(method string, status int) {
+	observer := p.histogram.With(prometheus.Labels{"method": method, "status": fmt.Sprint(status), "result": "unknown"})
+	p.observe(observer)
+}
+
+func (p *PrometheusMetrics) observe(observer prometheus.Observer) {
+	elapsed := time.Now().Sub(p.startedAt)
+	observer.Observe(float64(elapsed.Milliseconds()))
+}
+
+type PrometheusMetricsFactory struct {
+	metricName string
+}
+
+func NewPrometheusMetricsFactory(config PrometheusConfig) (MetricsFactory, error) {
+	log.Printf("prometheus config: %+v\n", config)
+
+	serveMux := http.NewServeMux()
+	serveMux.Handle(config.ScrapePath, promhttp.Handler())
+	server := http.Server{
+		Addr:    config.Host + ":" + config.Port,
+		Handler: serveMux,
+	}
+
+	go func() {
+		log.Printf("Listening for Prometheus scrapes on %s:%s\n", config.Host, config.Port)
+		log.Fatal(server.ListenAndServe())
+	}()
+
+	return &PrometheusMetricsFactory{metricName: config.MetricName}, nil
+}
+
+func (p PrometheusMetricsFactory) Create(eventName string) Metrics {
+	histogram := prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Name: p.metricName,
+	}, []string{"eventName", "status", "method", "result"})
+
+	if err := prometheus.Register(histogram); err != nil {
+		are := &prometheus.AlreadyRegisteredError{}
+		if errors.As(err, are) {
+			// Use previously registered metric collector
+			histogram = are.ExistingCollector.(*prometheus.HistogramVec)
+		} else {
+			// There's no other reason prometheus.Register should fail and the interface won't let
+			// us return an error.
+			panic(err)
+		}
+	}
+
+	return &PrometheusMetrics{
+		startedAt: time.Now(),
+		histogram: histogram.MustCurryWith(prometheus.Labels{"eventName": eventName}),
+	}
+}