diff --git a/lib/github-auth.js b/lib/github-auth.js
index 3eeeaf7..d971c4b 100644
--- a/lib/github-auth.js
+++ b/lib/github-auth.js
@@ -11,9 +11,13 @@ try {
   serverSecrets = require('../secret.json');
 } catch(e) {}
 var githubUserTokens;
-autosave('.github-user-tokens.json', {data:[]}).then(function(f) {
+var githubUserTokensFile = '.github-user-tokens.json';
+autosave(githubUserTokensFile, {data:[]}).then(function(f) {
   githubUserTokens = f;
-}).catch(function(e) { console.error('Could not create github-user-tokens.json'); });
+  for (var i = 0; i < githubUserTokens.length; i++) {
+    addGithubToken(githubUserTokens.data[i]);
+  }
+}).catch(function(e) { console.error('Could not create ' + githubUserTokensFile); });
 
 function setRoutes(server) {
   server.route(/^\/github-auth$/, function(data, match, end, ask) {
@@ -75,10 +79,7 @@ function setRoutes(server) {
       // An unknown entity tries to connect. Let the connection linger for a minute.
       return setTimeout(function() { end('Invalid secret'); }, 60000);
     }
-    // Insert it only if it is not registered yet.
-    if (githubUserTokens.data.indexOf(data.token) === -1) {
-      githubUserTokens.data.push(data.token);
-    }
+    addGithubToken(data.token);
     end('Thanks!');
   });
 };
@@ -112,4 +113,62 @@ function sendTokenToAllServers(token) {
   }));
 }
 
+// Track rate limit requests remaining.
+
+var reqRemaining = new Map();
+var lowestReqRemaining, lowestReqRemainingToken;
+
+// token: client token as a string.
+// reqs: number of requests remaining.
+function setReqRemaining(token, reqs) {
+  if (reqs < lowestReqRemaining) {
+    lowestReqRemaining = reqs;
+    lowestReqRemainingToken = token;
+  }
+  reqRemaining.set(token, reqs);
+}
+
+function addGithubToken(token) {
+  setReqRemaining(token, Infinity);
+  // Insert it only if it is not registered yet.
+  if (githubUserTokens.data.indexOf(token) === -1) {
+    githubUserTokens.data.push(token);
+  }
+}
+
+// Personal tokens allow access to GitHub private repositories.
+// You can manage your personal GitHub token at
+// <https://github.com/settings/tokens>.
+if (serverSecrets && serverSecrets.gh_token) {
+  addGithubToken(serverSecrets.gh_token);
+}
+
+// Modify headers, return a URL (or an object to be used by request()).
+function githubRequest(request, url, cb) {
+  var headers = {
+    'User-Agent': 'Shields.io',
+    'Accept': 'application/vnd.github.v3+json',
+  };
+  var token;
+
+  if (lowestReqRemainingToken != null) {
+    token = lowestReqRemainingToken;
+    headers['Authorization'] = 'token ' + token;
+  } else if (serverSecrets && serverSecrets.gh_client_id) {
+    // Using our OAuth App secret grants us 5000 req/hour
+    // instead of the standard 60 req/hour.
+    apiUrl += '?client_id=' + serverSecrets.gh_client_id
+      + '&client_secret=' + serverSecrets.gh_client_secret;
+  }
+
+  request(url, {headers: headers}, function(err, res, buffer) {
+    if (token != null) {
+      var remaining = +res.headers['x-ratelimit-remaining'];
+      setReqRemaining(token, remaining);
+    }
+    cb(err, res, buffer);
+  });
+}
+
 exports.setRoutes = setRoutes;
+exports.githubRequest = githubRequest;