diff --git a/dev-test/backends/proxy/config.yml b/dev-test/backends/proxy/config.yml
index cefad1a1..4c07e4dd 100644
--- a/dev-test/backends/proxy/config.yml
+++ b/dev-test/backends/proxy/config.yml
@@ -1,11 +1,15 @@
 backend:
-  name: proxy
+  name: github
   branch: master
-  proxy_url: http://localhost:8082/api/v1
+  repo: owner/repo
 
 publish_mode: editorial_workflow
 media_folder: static/media
 public_folder: /media
+
+local_backend:
+  url: http://localhost:8082/api/v1
+
 collections:
   - name: posts
     label: Posts
diff --git a/packages/netlify-cms-core/src/actions/__tests__/config.spec.js b/packages/netlify-cms-core/src/actions/__tests__/config.spec.js
index 922ee800..f2a6173a 100644
--- a/packages/netlify-cms-core/src/actions/__tests__/config.spec.js
+++ b/packages/netlify-cms-core/src/actions/__tests__/config.spec.js
@@ -1,5 +1,7 @@
 import { fromJS } from 'immutable';
-import { applyDefaults } from '../config';
+import { applyDefaults, detectProxyServer } from '../config';
+
+jest.spyOn(console, 'log').mockImplementation(() => {});
 
 describe('config', () => {
   describe('applyDefaults', () => {
@@ -168,4 +170,66 @@ describe('config', () => {
       });
     });
   });
+
+  describe('detectProxyServer', () => {
+    const assetFetchCalled = (url = 'http://localhost:8081/api/v1') => {
+      expect(global.fetch).toHaveBeenCalledTimes(1);
+      expect(global.fetch).toHaveBeenCalledWith(url, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ action: 'info' }),
+      });
+    };
+
+    beforeEach(() => {
+      delete window.location;
+    });
+
+    it('should return undefined when not on localhost', async () => {
+      window.location = { hostname: 'www.netlify.com' };
+      global.fetch = jest.fn();
+      await expect(detectProxyServer()).resolves.toBeUndefined();
+
+      expect(global.fetch).toHaveBeenCalledTimes(0);
+    });
+
+    it('should return undefined when fetch returns an error', async () => {
+      window.location = { hostname: 'localhost' };
+      global.fetch = jest.fn().mockRejectedValue(new Error());
+      await expect(detectProxyServer(true)).resolves.toBeUndefined();
+
+      assetFetchCalled();
+    });
+
+    it('should return undefined when fetch returns an invalid response', async () => {
+      window.location = { hostname: 'localhost' };
+      global.fetch = jest
+        .fn()
+        .mockResolvedValue({ json: jest.fn().mockResolvedValue({ repo: [] }) });
+      await expect(detectProxyServer(true)).resolves.toBeUndefined();
+
+      assetFetchCalled();
+    });
+
+    it('should return proxyUrl when fetch returns a valid response', async () => {
+      window.location = { hostname: 'localhost' };
+      global.fetch = jest
+        .fn()
+        .mockResolvedValue({ json: jest.fn().mockResolvedValue({ repo: 'test-repo' }) });
+      await expect(detectProxyServer(true)).resolves.toBe('http://localhost:8081/api/v1');
+
+      assetFetchCalled();
+    });
+
+    it('should use local_backend url', async () => {
+      const url = 'http://localhost:8082/api/v1';
+      window.location = { hostname: 'localhost' };
+      global.fetch = jest
+        .fn()
+        .mockResolvedValue({ json: jest.fn().mockResolvedValue({ repo: 'test-repo' }) });
+      await expect(detectProxyServer({ url })).resolves.toBe(url);
+
+      assetFetchCalled(url);
+    });
+  });
 });
diff --git a/packages/netlify-cms-core/src/actions/config.js b/packages/netlify-cms-core/src/actions/config.js
index 973affb1..93fd878f 100644
--- a/packages/netlify-cms-core/src/actions/config.js
+++ b/packages/netlify-cms-core/src/actions/config.js
@@ -1,6 +1,6 @@
 import yaml from 'js-yaml';
 import { Map, fromJS } from 'immutable';
-import { trimStart, get } from 'lodash';
+import { trimStart, get, isPlainObject } from 'lodash';
 import { authenticateUser } from 'Actions/auth';
 import * as publishModes from 'Constants/publishModes';
 import { validateConfig } from 'Constants/configSchema';
@@ -145,6 +145,31 @@ export function mergeConfig(config) {
   return { type: CONFIG_MERGE, payload: config };
 }
 
+export async function detectProxyServer(localBackend) {
+  if (location.hostname === 'localhost' || location.hostname === '127.0.0.1') {
+    let proxyUrl;
+    if (localBackend === true) {
+      proxyUrl = 'http://localhost:8081/api/v1';
+    } else if (isPlainObject(localBackend)) {
+      proxyUrl = localBackend.url;
+    }
+    try {
+      console.log(`Looking for Netlify CMS Proxy Server at '${proxyUrl}'`);
+      const { repo } = await fetch(`${proxyUrl}`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ action: 'info' }),
+      }).then(res => res.json());
+      if (typeof repo === 'string') {
+        console.log(`Detected Netlify CMS Proxy Server at '${proxyUrl}' with repo: '${repo}'`);
+        return proxyUrl;
+      }
+    } catch {
+      console.log(`Netlify CMS Proxy Server not detected at '${proxyUrl}'`);
+    }
+  }
+}
+
 export function loadConfig() {
   if (window.CMS_CONFIG) {
     return configDidLoad(fromJS(window.CMS_CONFIG));
@@ -155,17 +180,29 @@ export function loadConfig() {
     try {
       const preloadedConfig = getState().config;
       const configUrl = getConfigUrl();
+      const isPreloaded = preloadedConfig && preloadedConfig.size > 1;
       const loadedConfig =
         preloadedConfig && preloadedConfig.get('load_config_file') === false
           ? {}
-          : await getConfig(configUrl, preloadedConfig && preloadedConfig.size > 1);
+          : await getConfig(configUrl, isPreloaded);
 
       /**
        * Merge any existing configuration so the result can be validated.
        */
-      const mergedConfig = mergePreloadedConfig(preloadedConfig, loadedConfig);
+      let mergedConfig = mergePreloadedConfig(preloadedConfig, loadedConfig);
+
       validateConfig(mergedConfig.toJS());
 
+      // detect running Netlify CMS proxy
+      if (mergedConfig.has('local_backend')) {
+        const proxyUrl = await detectProxyServer(mergedConfig.toJS().local_backend);
+        if (proxyUrl) {
+          mergedConfig = mergePreloadedConfig(mergedConfig, {
+            backend: { name: 'proxy', proxy_url: proxyUrl },
+          });
+        }
+      }
+
       const config = applyDefaults(mergedConfig);
 
       dispatch(configDidLoad(config));
diff --git a/packages/netlify-cms-core/src/constants/__tests__/configSchema.spec.js b/packages/netlify-cms-core/src/constants/__tests__/configSchema.spec.js
index 6407f86a..46fa29dd 100644
--- a/packages/netlify-cms-core/src/constants/__tests__/configSchema.spec.js
+++ b/packages/netlify-cms-core/src/constants/__tests__/configSchema.spec.js
@@ -126,5 +126,31 @@ describe('config', () => {
         });
       }).toThrowError("'collections[0]' should be object");
     });
+
+    it('should throw if local_backend is not a boolean or plain object', () => {
+      expect(() => {
+        validateConfig(merge(validConfig, { local_backend: [] }));
+      }).toThrowError("'local_backend' should be boolean");
+    });
+
+    it('should throw if local_backend is a plain object but missing url property', () => {
+      expect(() => {
+        validateConfig(merge(validConfig, { local_backend: {} }));
+      }).toThrowError("'local_backend' should be object");
+    });
+
+    it('should not throw if local_backend is a boolean', () => {
+      expect(() => {
+        validateConfig(merge(validConfig, { local_backend: true }));
+      }).not.toThrowError();
+    });
+
+    it('should not throw if local_backend is a plain object with url property', () => {
+      expect(() => {
+        validateConfig(
+          merge(validConfig, { local_backend: { url: 'http://localhost:8081/api/v1' } }),
+        );
+      }).not.toThrowError();
+    });
   });
 });
diff --git a/packages/netlify-cms-core/src/constants/configSchema.js b/packages/netlify-cms-core/src/constants/configSchema.js
index 1f2c6ac8..5bb2bbdc 100644
--- a/packages/netlify-cms-core/src/constants/configSchema.js
+++ b/packages/netlify-cms-core/src/constants/configSchema.js
@@ -42,6 +42,18 @@ const getConfigSchema = () => ({
       },
       required: ['name'],
     },
+    local_backend: {
+      oneOf: [
+        { type: 'boolean' },
+        {
+          type: 'object',
+          properties: {
+            url: { type: 'string', examples: ['http://localhost:8081/api/v1'] },
+          },
+          required: ['url'],
+        },
+      ],
+    },
     locale: { type: 'string', examples: ['en', 'fr', 'de'] },
     site_url: { type: 'string', examples: ['https://example.com'] },
     display_url: { type: 'string', examples: ['https://example.com'] },
diff --git a/website/content/docs/beta-features.md b/website/content/docs/beta-features.md
index f4a57e55..7ece9999 100644
--- a/website/content/docs/beta-features.md
+++ b/website/content/docs/beta-features.md
@@ -14,18 +14,20 @@ You can connect Netlify CMS to a local Git repository, instead of working with a
 
 1. Navigate to a local Git repository configured with the CMS.
 2. Run `npx netlify-cms-proxy-server` from the root directory of the above repository.
-3. Update your `config.yml` to connect to the server:
+3. Add the `local_backend` configuration to your `config.yml`:
 
 ```yaml
-backend:
-  name: proxy
-  proxy_url: http://localhost:8081/api/v1
-  branch: master # optional, defaults to master
+# when using the default proxy server port
+local_backend: true
+
+# when using a custom proxy server port
+local_backend:
+  url: http://localhost:8082/api/v1
 ```
 
-4. Start you local development server (e.g. run `gatsby develop`).
+4. Start your local development server (e.g. run `gatsby develop`).
 
-> `netlify-cms-proxy-server` runs an unauthenticated express server. As any client can send requests to the server, it should only be used for local development.
+**Note:** `netlify-cms-proxy-server` runs an unauthenticated express server. As any client can send requests to the server, it should only be used for local development.
 
 ## GitLab and BitBucket Editorial Workflow Support