diff --git a/README.md b/README.md
index 3123ec3f4af..88eca06e7ef 100644
--- a/README.md
+++ b/README.md
@@ -238,7 +238,7 @@ To learn more about the Nightscout API, visit https://YOUR-SITE.com/api-docs/ or
 ### Required
 
   * `MONGODB_URI` - The connection string for your Mongo database. Something like `mongodb://sally:sallypass@ds099999.mongolab.com:99999/nightscout`.
-  * `API_SECRET` - A secret passphrase that must be at least 12 characters long.
+  * `API_SECRET` - A secret passphrase that must be at least 12 characters long. Alternatively, if `API_SECRET_FILE` is defined, the secret passphrase will be read from the specified file.
   * `MONGODB_COLLECTION` (`entries`) - The Mongo collection where CGM entries are stored.
   * `DISPLAY_UNITS` (`mg/dl`) - Options are `mg/dl` or `mmol/L` (or just `mmol`).  Setting to `mmol/L` puts the entire server into `mmol/L` mode by default, no further settings needed.
 
diff --git a/lib/server/enclave.js b/lib/server/enclave.js
index 03dc8facf96..ff02dbc5ec3 100644
--- a/lib/server/enclave.js
+++ b/lib/server/enclave.js
@@ -44,7 +44,7 @@ const init = function init () {
   }
 
   enclave.isApiKeySet = function isApiKeySet () {
-    return isApiKeySet;
+    return apiKeySet;
   }
 
   enclave.isApiKey = function isApiKey (keyValue) {
diff --git a/lib/server/env.js b/lib/server/env.js
index afb53d51332..7e316f05524 100644
--- a/lib/server/env.js
+++ b/lib/server/env.js
@@ -77,22 +77,19 @@ function setSSL () {
   env.secureCspReportOnly = readENVTruthy("SECURE_CSP_REPORT_ONLY", false);
 }
 
-// A little ugly, but we don't want to read the secret into a var
 function setAPISecret () {
-  var useSecret = (readENV('API_SECRET') && readENV('API_SECRET').length > 0);
+  // if no value is provided as an environment variable, try to read it from a file
+  const apiSecret = readENV('API_SECRET') || readEnvFile('API_SECRET_FILE');
   //TODO: should we clear API_SECRET from process env?
   env.api_secret = null;
   // if a passphrase was provided, get the hex digest to mint a single token
-  if (useSecret) {
-    if (readENV('API_SECRET').length < consts.MIN_PASSPHRASE_LENGTH) {
+  if (apiSecret && apiSecret.length > 0) {
+    if (apiSecret.length < consts.MIN_PASSPHRASE_LENGTH) {
       var msg = ['API_SECRET should be at least', consts.MIN_PASSPHRASE_LENGTH, 'characters'].join(' ');
       console.error(msg);
       env.err.push({ desc: msg });
     } else {
-
-      const apiSecret = readENV('API_SECRET');
       delete process.env.API_SECRET;
-
       env.enclave.setApiKey(apiSecret);
       var testresult = stringEntropy(apiSecret);
 
@@ -108,7 +105,6 @@ function setAPISecret () {
           env.notifies.push({ persistent: true, title: 'Security issue', message: 'MongoDB password and API_SECRET match. This is a really bad idea. Please change both and do not reuse passwords across the system.' });
         }
       }
-
     }
   }
 }
@@ -185,6 +181,21 @@ function readENVTruthy (varName, defaultValue) {
   return value;
 }
 
+function readEnvFile(varName) {
+  let value = null;
+  const fileName = readENV(varName);
+
+  if (fileName && fileName.length > 0) {
+    try {
+      value = fs.readFileSync(fileName);
+    } catch (error) {
+      env.err.push({ desc: `Unable to read ${varName}: ${error.message}` });
+    }
+  }
+
+  return value;
+}
+
 function findExtendedSettings (envs) {
   var extended = {};
 
diff --git a/tests/env.test.js b/tests/env.test.js
index 0de2a686054..0e3e0f4f5d0 100644
--- a/tests/env.test.js
+++ b/tests/env.test.js
@@ -1,8 +1,71 @@
 'use strict';
 
 require('should');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
 
 describe('env', function () {
+  function writeTempFile(fileName, data) {
+    const fullPath = path.join(os.tmpdir(), fileName);
+    fs.writeFileSync(fullPath, data);
+    return fullPath;
+  }
+
+  it('should not set the API key without API_SECRET or API_SECRET_FILE', function () {
+    delete process.env.API_SECRET;
+    var env = require( '../lib/server/env' )();
+    env.enclave.isApiKeySet().should.equal(false);
+  });
+
+  it('should read the API key from API_SECRET_FILE if it is valid', function () {
+    const apiSecretFile = 'this is another pass phrase';
+    const hashFile = 'c79c6db1070da3537d0162e60647b0a588769f8d';
+    process.env.API_SECRET_FILE = writeTempFile('api_secret_file', apiSecretFile);
+
+    var env = require( '../lib/server/env' )();
+    env.enclave.isApiKeySet().should.equal(true);
+    env.enclave.isApiKey(hashFile).should.equal(true);
+
+    fs.rmSync(process.env.API_SECRET_FILE);
+    delete process.env.API_SECRET_FILE;
+  });
+
+  it('should raise an error when API_SECRET_FILE does not exist', function () {
+    const nonexistentPath = path.join(os.tmpdir(), 'api_secret_file');
+    process.env.API_SECRET_FILE = nonexistentPath;
+
+    var env = require( '../lib/server/env' )();
+    env.enclave.isApiKeySet().should.equal(false);
+    env.err.length.should.equal(1);
+
+    const error = env.err.pop();
+    error.should.have.property('desc');
+    error.desc.should.match(/API_SECRET_FILE/);
+    error.desc.should.match(/no such file or directory/);
+
+    delete process.env.API_SECRET_FILE;
+  });
+
+  it('should use API_SECRET when API_SECRET_FILE is also specified', function () {
+    const apiSecretEnv = 'this is my long pass phrase';
+    const hashEnv = 'b723e97aa97846eb92d5264f084b2823f57c4aa1';
+    process.env.API_SECRET = apiSecretEnv;
+
+    const apiSecretFile = 'this is another pass phrase';
+    const hashFile = 'c79c6db1070da3537d0162e60647b0a588769f8d';
+    process.env.API_SECRET_FILE = writeTempFile('api_secret_file', apiSecretFile);
+
+    var env = require( '../lib/server/env' )();
+    env.enclave.isApiKeySet().should.equal(true);
+    env.enclave.isApiKey(hashEnv).should.equal(true);
+    env.enclave.isApiKey(hashFile).should.equal(false);
+
+    fs.rmSync(process.env.API_SECRET_FILE);
+    delete process.env.API_SECRET_FILE;
+    delete process.env.API_SECRET;
+  });
+
   it( 'show the right plugins', function () {
     process.env.SHOW_PLUGINS = 'iob';
     process.env.ENABLE = 'iob cob';