diff --git a/keyserver/package.json b/keyserver/package.json
--- a/keyserver/package.json
+++ b/keyserver/package.json
@@ -16,6 +16,7 @@
     "clear-profile-logs": "rm -rf cpu_profiling_logs/",
     "dev-rsync": "yarn --silent chokidar --initial --silent -s 'src/**/*.json' 'src/**/*.cjs' -c 'yarn rsync > /dev/null 2>&1'",
     "dev": ". bash/source-nvm.sh && yarn concurrently --names=\"BABEL,RSYNC,NODEM\" -c \"bgBlue.bold,bgMagenta.bold,bgGreen.bold\" \"yarn babel-build --source-maps --watch\" \"yarn dev-rsync\" \". bash/source-nvm.sh && KEYSERVER=true NODE_ENV=development nodemon -e js,json,cjs --watch dist --no-warnings=ExperimentalWarning --loader=./loader.mjs dist/keyserver\"",
+    "dev-log-metrics": "KEYSERVER_ENDPOINT_METRICS_ENABLED=true yarn dev",
     "script": ". bash/source-nvm.sh && NODE_ENV=development node --loader=./loader.mjs",
     "test": "jest"
   },
diff --git a/keyserver/src/keyserver.js b/keyserver/src/keyserver.js
--- a/keyserver/src/keyserver.js
+++ b/keyserver/src/keyserver.js
@@ -14,6 +14,7 @@
 
 import { migrate } from './database/migrations.js';
 import { jsonEndpoints } from './endpoints.js';
+import { logEndpointMetrics } from './middleware/endpoint_profiling.js';
 import { emailSubscriptionResponder } from './responders/comm-landing-responders.js';
 import {
   jsonHandler,
@@ -61,6 +62,8 @@
       : { maxAge: '1y', immutable: true };
 
   const isCPUProfilingEnabled = process.env.KEYSERVER_CPU_PROFILING_ENABLED;
+  const areEndpointMetricsEnabled =
+    process.env.KEYSERVER_ENDPOINT_METRICS_ENABLED;
 
   if (cluster.isMaster) {
     const didMigrationsSucceed: boolean = await migrate();
@@ -121,6 +124,9 @@
     server.use(cookieParser());
 
     const setupAppRouter = router => {
+      if (areEndpointMetricsEnabled) {
+        router.use(logEndpointMetrics);
+      }
       router.use('/images', express.static('images'));
       router.use('/fonts', express.static('fonts'));
       router.use('/misc', express.static('misc'));
diff --git a/keyserver/src/middleware/endpoint_profiling.js b/keyserver/src/middleware/endpoint_profiling.js
new file mode 100644
--- /dev/null
+++ b/keyserver/src/middleware/endpoint_profiling.js
@@ -0,0 +1,27 @@
+// @flow
+
+import type { $Request, $Response, NextFunction } from 'express';
+
+function logEndpointMetrics(
+  req: $Request,
+  res: $Response,
+  next: NextFunction,
+): void {
+  const endpointName = req.url;
+  const requestTime = Date.now();
+
+  const onCompletion = () => {
+    const responseTime = Date.now();
+    const endpointDuration = responseTime - requestTime;
+    const contentSize = res.get('Content-Length') ?? 'NaN';
+    console.log(
+      `${endpointName}, ${endpointDuration.toFixed(2)}ms, ${contentSize} bytes`,
+    );
+  };
+
+  res.on('finish', onCompletion);
+
+  next();
+}
+
+export { logEndpointMetrics };