diff --git a/circle.yml b/circle.yml
index 6966d8f3b0f..d15a99c006c 100644
--- a/circle.yml
+++ b/circle.yml
@@ -1256,9 +1256,8 @@ jobs:
       - test-binary-against-repo:
           repo: cypress-example-recipes
           command: npm run test:ci
-          # https://github.com/cypress-io/cypress-example-recipes/pull/501
-          pull_request_id: 501
-          folder: examples/unit-testing__lit-element
+          pull_request_id: 503
+          folder: examples/stubbing-spying__window-fetch
 
   "test-binary-against-kitchensink":
     <<: *defaults
@@ -1569,11 +1568,11 @@ linux-workflow: &linux-workflow
           - build-binary
           - build-npm-package
     - test-binary-against-recipe-pull-request:
-        name: Shadow DOM recipe
+        name: Test fetch polyfill
         filters:
           branches:
             only:
-              - pull/7469
+              - polyfill-fetch
         requires:
           - build-binary
           - build-npm-package
diff --git a/cli/schema/cypress.schema.json b/cli/schema/cypress.schema.json
index c0906227a57..f68a30ee6c1 100644
--- a/cli/schema/cypress.schema.json
+++ b/cli/schema/cypress.schema.json
@@ -237,7 +237,12 @@
     "experimentalShadowDomSupport": {
       "type": "boolean",
       "default": false,
-      "description": "Enables shadow DOM support. Adds the `cy.shadow()` command and the `includeShadowDom` option to some DOM commands."
+      "description": "Enables shadow DOM support. Adds the `cy.shadow()` command and the `ignoreShadowBoundaries` option to some DOM commands."
+    },
+    "experimentalFetchPolyfill": {
+      "type": "boolean",
+      "default": false,
+      "description": "Polyfills `window.fetch` to enable Network spying and stubbing"
     }
   }
 }
diff --git a/packages/driver/README.md b/packages/driver/README.md
index 64a6ee6c5a4..61245b2eeca 100644
--- a/packages/driver/README.md
+++ b/packages/driver/README.md
@@ -44,6 +44,13 @@ In the browser
 localStorage.debug = "cypress:driver"
 ```
 
+## Patches
+
+- `sinon`
+- `unfetch` to polyfill `fetch`. Added constructor function to point XMLHttpRequest to the application under test window.
+
+Note: when creating a patch, make sure there is no `package-lock.json` file! Also rename the patch to have ".dev.patch" extension.
+
 <!-- ## Catalog of Events
 
 TODO: this data is accurate but also somewhat out of date.
diff --git a/packages/driver/package.json b/packages/driver/package.json
index 6da4b177d04..ad0a7deb8b7 100644
--- a/packages/driver/package.json
+++ b/packages/driver/package.json
@@ -65,6 +65,7 @@
     "text-mask-addons": "3.8.0",
     "underscore": "1.9.1",
     "underscore.string": "3.3.5",
+    "unfetch": "4.1.0",
     "url-parse": "1.4.7",
     "vanilla-text-mask": "5.1.1",
     "webpack": "4.41.2",
diff --git a/packages/driver/patches/unfetch+4.1.0.dev.patch b/packages/driver/patches/unfetch+4.1.0.dev.patch
new file mode 100644
index 00000000000..263ad9691c2
--- /dev/null
+++ b/packages/driver/patches/unfetch+4.1.0.dev.patch
@@ -0,0 +1,119 @@
+diff --git a/node_modules/unfetch/dist/unfetch.es.js b/node_modules/unfetch/dist/unfetch.es.js
+deleted file mode 100644
+index af22f48..0000000
+--- a/node_modules/unfetch/dist/unfetch.es.js
++++ /dev/null
+@@ -1,2 +0,0 @@
+-export default function(e,n){return n=n||{},new Promise(function(t,r){var s=new XMLHttpRequest,o=[],u=[],i={},a=function(){return{ok:2==(s.status/100|0),statusText:s.statusText,status:s.status,url:s.responseURL,text:function(){return Promise.resolve(s.responseText)},json:function(){return Promise.resolve(JSON.parse(s.responseText))},blob:function(){return Promise.resolve(new Blob([s.response]))},clone:a,headers:{keys:function(){return o},entries:function(){return u},get:function(e){return i[e.toLowerCase()]},has:function(e){return e.toLowerCase()in i}}}};for(var l in s.open(n.method||"get",e,!0),s.onload=function(){s.getAllResponseHeaders().replace(/^(.*?):[^\S\n]*([\s\S]*?)$/gm,function(e,n,t){o.push(n=n.toLowerCase()),u.push([n,t]),i[n]=i[n]?i[n]+","+t:t}),t(a())},s.onerror=r,s.withCredentials="include"==n.credentials,n.headers)s.setRequestHeader(l,n.headers[l]);s.send(n.body||null)})}
+-//# sourceMappingURL=unfetch.mjs.map
+diff --git a/node_modules/unfetch/dist/unfetch.es.js.map b/node_modules/unfetch/dist/unfetch.es.js.map
+deleted file mode 100644
+index efa624a..0000000
+--- a/node_modules/unfetch/dist/unfetch.es.js.map
++++ /dev/null
+@@ -1 +0,0 @@
+-{"version":3,"file":"unfetch.es.js","sources":["../src/index.js"],"sourcesContent":["export default typeof fetch=='function' ? fetch.bind() : function(url, options) {\n\toptions = options || {};\n\treturn new Promise( (resolve, reject) => {\n\t\tlet request = new XMLHttpRequest();\n\n\t\trequest.open(options.method || 'get', url, true);\n\n\t\tfor (let i in options.headers) {\n\t\t\trequest.setRequestHeader(i, options.headers[i]);\n\t\t}\n\n\t\trequest.withCredentials = options.credentials=='include';\n\n\t\trequest.onload = () => {\n\t\t\tresolve(response());\n\t\t};\n\n\t\trequest.onerror = reject;\n\n\t\trequest.send(options.body || null);\n\n\t\tfunction response() {\n\t\t\tlet keys = [],\n\t\t\t\tall = [],\n\t\t\t\theaders = {},\n\t\t\t\theader;\n\n\t\t\trequest.getAllResponseHeaders().replace(/^(.*?):[^\\S\\n]*([\\s\\S]*?)$/gm, (m, key, value) => {\n\t\t\t\tkeys.push(key = key.toLowerCase());\n\t\t\t\tall.push([key, value]);\n\t\t\t\theader = headers[key];\n\t\t\t\theaders[key] = header ? `${header},${value}` : value;\n\t\t\t});\n\n\t\t\treturn {\n\t\t\t\tok: (request.status/100|0) == 2,\t\t// 200-299\n\t\t\t\tstatus: request.status,\n\t\t\t\tstatusText: request.statusText,\n\t\t\t\turl: request.responseURL,\n\t\t\t\tclone: response,\n\t\t\t\ttext: () => Promise.resolve(request.responseText),\n\t\t\t\tjson: () => Promise.resolve(request.responseText).then(JSON.parse),\n\t\t\t\tblob: () => Promise.resolve(new Blob([request.response])),\n\t\t\t\theaders: {\n\t\t\t\t\tkeys: () => keys,\n\t\t\t\t\tentries: () => all,\n\t\t\t\t\tget: n => headers[n.toLowerCase()],\n\t\t\t\t\thas: n => n.toLowerCase() in headers\n\t\t\t\t}\n\t\t\t};\n\t\t}\n\t});\n}\n"],"names":["let"],"mappings":"AAAA,YAAe,OAAO,KAAK,EAAE,UAAU,GAAG,KAAK,CAAC,IAAI,EAAE,GAAG,SAAS,GAAG,EAAE,OAAO,EAAE;CAC/E,OAAO,GAAG,OAAO,IAAI,EAAE,CAAC;CACxB,OAAO,IAAI,OAAO,EAAE,UAAC,OAAO,EAAE,MAAM,EAAE;EACrCA,IAAI,OAAO,GAAG,IAAI,cAAc,EAAE,CAAC;;EAEnC,OAAO,CAAC,IAAI,CAAC,OAAO,CAAC,MAAM,IAAI,KAAK,EAAE,GAAG,EAAE,IAAI,CAAC,CAAC;;EAEjD,KAAKA,IAAI,CAAC,IAAI,OAAO,CAAC,OAAO,EAAE;GAC9B,OAAO,CAAC,gBAAgB,CAAC,CAAC,EAAE,OAAO,CAAC,OAAO,CAAC,CAAC,CAAC,CAAC,CAAC;GAChD;;EAED,OAAO,CAAC,eAAe,GAAG,OAAO,CAAC,WAAW,EAAE,SAAS,CAAC;;EAEzD,OAAO,CAAC,MAAM,GAAG,YAAG;GACnB,OAAO,CAAC,QAAQ,EAAE,CAAC,CAAC;GACpB,CAAC;;EAEF,OAAO,CAAC,OAAO,GAAG,MAAM,CAAC;;EAEzB,OAAO,CAAC,IAAI,CAAC,OAAO,CAAC,IAAI,IAAI,IAAI,CAAC,CAAC;;EAEnC,SAAS,QAAQ,GAAG;GACnBA,IAAI,IAAI,GAAG,EAAE;IACZ,GAAG,GAAG,EAAE;IACR,OAAO,GAAG,EAAE;IACZ,MAAM,CAAC;;GAER,OAAO,CAAC,qBAAqB,EAAE,CAAC,OAAO,CAAC,8BAA8B,EAAE,UAAC,CAAC,EAAE,GAAG,EAAE,KAAK,EAAE;IACvF,IAAI,CAAC,IAAI,CAAC,GAAG,GAAG,GAAG,CAAC,WAAW,EAAE,CAAC,CAAC;IACnC,GAAG,CAAC,IAAI,CAAC,CAAC,GAAG,EAAE,KAAK,CAAC,CAAC,CAAC;IACvB,MAAM,GAAG,OAAO,CAAC,GAAG,CAAC,CAAC;IACtB,OAAO,CAAC,GAAG,CAAC,GAAG,MAAM,IAAG,MAAS,MAAE,GAAE,KAAK,IAAK,KAAK,CAAC;IACrD,CAAC,CAAC;;GAEH,OAAO;IACN,EAAE,EAAE,CAAC,OAAO,CAAC,MAAM,CAAC,GAAG,CAAC,CAAC,KAAK,CAAC;IAC/B,MAAM,EAAE,OAAO,CAAC,MAAM;IACtB,UAAU,EAAE,OAAO,CAAC,UAAU;IAC9B,GAAG,EAAE,OAAO,CAAC,WAAW;IACxB,KAAK,EAAE,QAAQ;IACf,IAAI,EAAE,YAAG,SAAG,OAAO,CAAC,OAAO,CAAC,OAAO,CAAC,YAAY,CAAC,GAAA;IACjD,IAAI,EAAE,YAAG,SAAG,OAAO,CAAC,OAAO,CAAC,OAAO,CAAC,YAAY,CAAC,CAAC,IAAI,CAAC,IAAI,CAAC,KAAK,CAAC,GAAA;IAClE,IAAI,EAAE,YAAG,SAAG,OAAO,CAAC,OAAO,CAAC,IAAI,IAAI,CAAC,CAAC,OAAO,CAAC,QAAQ,CAAC,CAAC,CAAC,GAAA;IACzD,OAAO,EAAE;KACR,IAAI,EAAE,YAAG,SAAG,IAAI,GAAA;KAChB,OAAO,EAAE,YAAG,SAAG,GAAG,GAAA;KAClB,GAAG,EAAE,UAAA,CAAC,EAAC,SAAG,OAAO,CAAC,CAAC,CAAC,WAAW,EAAE,CAAC,GAAA;KAClC,GAAG,EAAE,UAAA,CAAC,EAAC,SAAG,CAAC,CAAC,WAAW,EAAE,IAAI,OAAO,GAAA;KACpC;IACD,CAAC;GACF;EACD,CAAC,CAAC;CACH,CAAA;;"}
+\ No newline at end of file
+diff --git a/node_modules/unfetch/dist/unfetch.js b/node_modules/unfetch/dist/unfetch.js
+deleted file mode 100644
+index ccd2565..0000000
+--- a/node_modules/unfetch/dist/unfetch.js
++++ /dev/null
+@@ -1,2 +0,0 @@
+-module.exports=function(e,n){return n=n||{},new Promise(function(t,r){var s=new XMLHttpRequest,o=[],u=[],i={},a=function(){return{ok:2==(s.status/100|0),statusText:s.statusText,status:s.status,url:s.responseURL,text:function(){return Promise.resolve(s.responseText)},json:function(){return Promise.resolve(JSON.parse(s.responseText))},blob:function(){return Promise.resolve(new Blob([s.response]))},clone:a,headers:{keys:function(){return o},entries:function(){return u},get:function(e){return i[e.toLowerCase()]},has:function(e){return e.toLowerCase()in i}}}};for(var l in s.open(n.method||"get",e,!0),s.onload=function(){s.getAllResponseHeaders().replace(/^(.*?):[^\S\n]*([\s\S]*?)$/gm,function(e,n,t){o.push(n=n.toLowerCase()),u.push([n,t]),i[n]=i[n]?i[n]+","+t:t}),t(a())},s.onerror=r,s.withCredentials="include"==n.credentials,n.headers)s.setRequestHeader(l,n.headers[l]);s.send(n.body||null)})};
+-//# sourceMappingURL=unfetch.js.map
+diff --git a/node_modules/unfetch/dist/unfetch.js.map b/node_modules/unfetch/dist/unfetch.js.map
+deleted file mode 100644
+index 3507b3d..0000000
+--- a/node_modules/unfetch/dist/unfetch.js.map
++++ /dev/null
+@@ -1 +0,0 @@
+-{"version":3,"file":"unfetch.js","sources":["../src/index.mjs"],"sourcesContent":["export default function(url, options) {\n\toptions = options || {};\n\treturn new Promise( (resolve, reject) => {\n\t\tconst request = new XMLHttpRequest();\n\t\tconst keys = [];\n\t\tconst all = [];\n\t\tconst headers = {};\n\n\t\tconst response = () => ({\n\t\t\tok: (request.status/100|0) == 2,\t\t// 200-299\n\t\t\tstatusText: request.statusText,\n\t\t\tstatus: request.status,\n\t\t\turl: request.responseURL,\n\t\t\ttext: () => Promise.resolve(request.responseText),\n\t\t\tjson: () => Promise.resolve(JSON.parse(request.responseText)),\n\t\t\tblob: () => Promise.resolve(new Blob([request.response])),\n\t\t\tclone: response,\n\t\t\theaders: {\n\t\t\t\tkeys: () => keys,\n\t\t\t\tentries: () => all,\n\t\t\t\tget: n => headers[n.toLowerCase()],\n\t\t\t\thas: n => n.toLowerCase() in headers\n\t\t\t}\n\t\t});\n\n\t\trequest.open(options.method || 'get', url, true);\n\n\t\trequest.onload = () => {\n\t\t\trequest.getAllResponseHeaders().replace(/^(.*?):[^\\S\\n]*([\\s\\S]*?)$/gm, (m, key, value) => {\n\t\t\t\tkeys.push(key = key.toLowerCase());\n\t\t\t\tall.push([key, value]);\n\t\t\t\theaders[key] = headers[key] ? `${headers[key]},${value}` : value;\n\t\t\t});\n\t\t\tresolve(response());\n\t\t};\n\n\t\trequest.onerror = reject;\n\n\t\trequest.withCredentials = options.credentials=='include';\n\n\t\tfor (const i in options.headers) {\n\t\t\trequest.setRequestHeader(i, options.headers[i]);\n\t\t}\n\n\t\trequest.send(options.body || null);\n\t});\n}\n"],"names":["url","options","Promise","resolve","reject","request","XMLHttpRequest","keys","all","headers","response","ok","status","statusText","responseURL","text","responseText","json","JSON","parse","blob","Blob","clone","entries","get","n","toLowerCase","has","const","i","open","method","onload","getAllResponseHeaders","replace","m","key","value","push","onerror","withCredentials","credentials","setRequestHeader","send","body"],"mappings":"eAAe,SAASA,EAAKC,UAC5BA,EAAUA,GAAW,GACd,IAAIC,iBAAUC,EAASC,OACvBC,EAAU,IAAIC,eACdC,EAAO,GACPC,EAAM,GACNC,EAAU,GAEVC,oBACLC,GAA8B,IAAzBN,EAAQO,OAAO,IAAI,GACxBC,WAAYR,EAAQQ,WACpBD,OAAQP,EAAQO,OAChBZ,IAAKK,EAAQS,YACbC,uBAAYb,QAAQC,QAAQE,EAAQW,eACpCC,uBAAYf,QAAQC,QAAQe,KAAKC,MAAMd,EAAQW,gBAC/CI,uBAAYlB,QAAQC,QAAQ,IAAIkB,KAAK,CAAChB,EAAQK,aAC9CY,MAAOZ,EACPD,QAAS,CACRF,uBAAYA,GACZgB,0BAAef,GACfgB,aAAKC,UAAKhB,EAAQgB,EAAEC,gBACpBC,aAAKF,UAAKA,EAAEC,gBAAiBjB,UAmB1BmB,IAAMC,KAfXxB,EAAQyB,KAAK7B,EAAQ8B,QAAU,MAAO/B,GAAK,GAE3CK,EAAQ2B,kBACP3B,EAAQ4B,wBAAwBC,QAAQ,wCAAiCC,EAAGC,EAAKC,GAChF9B,EAAK+B,KAAKF,EAAMA,EAAIV,eACpBlB,EAAI8B,KAAK,CAACF,EAAKC,IACf5B,EAAQ2B,GAAO3B,EAAQ2B,GAAU3B,EAAQ2B,OAAQC,EAAUA,IAE5DlC,EAAQO,MAGTL,EAAQkC,QAAUnC,EAElBC,EAAQmC,gBAAuC,WAArBvC,EAAQwC,YAElBxC,EAAQQ,QACvBJ,EAAQqC,iBAAiBb,EAAG5B,EAAQQ,QAAQoB,IAG7CxB,EAAQsC,KAAK1C,EAAQ2C,MAAQ"}
+\ No newline at end of file
+diff --git a/node_modules/unfetch/dist/unfetch.mjs b/node_modules/unfetch/dist/unfetch.mjs
+index af22f48..23ed5a5 100644
+--- a/node_modules/unfetch/dist/unfetch.mjs
++++ b/node_modules/unfetch/dist/unfetch.mjs
+@@ -1,2 +1,3 @@
+-export default function(e,n){return n=n||{},new Promise(function(t,r){var s=new XMLHttpRequest,o=[],u=[],i={},a=function(){return{ok:2==(s.status/100|0),statusText:s.statusText,status:s.status,url:s.responseURL,text:function(){return Promise.resolve(s.responseText)},json:function(){return Promise.resolve(JSON.parse(s.responseText))},blob:function(){return Promise.resolve(new Blob([s.response]))},clone:a,headers:{keys:function(){return o},entries:function(){return u},get:function(e){return i[e.toLowerCase()]},has:function(e){return e.toLowerCase()in i}}}};for(var l in s.open(n.method||"get",e,!0),s.onload=function(){s.getAllResponseHeaders().replace(/^(.*?):[^\S\n]*([\s\S]*?)$/gm,function(e,n,t){o.push(n=n.toLowerCase()),u.push([n,t]),i[n]=i[n]?i[n]+","+t:t}),t(a())},s.onerror=r,s.withCredentials="include"==n.credentials,n.headers)s.setRequestHeader(l,n.headers[l]);s.send(n.body||null)})}
+-//# sourceMappingURL=unfetch.mjs.map
++export const registerFetch = (win) => {
++  return function(e,n){return n=n||{},new Promise((t,r) => {var s=new win.XMLHttpRequest,o=[],u=[],i={},a=function(){return{ok:2==(s.status/100|0),statusText:s.statusText,status:s.status,url:s.responseURL,text:function(){return Promise.resolve(s.responseText)},json:function(){return Promise.resolve(JSON.parse(s.responseText))},blob:function(){return Promise.resolve(new Blob([s.response]))},clone:a,headers:{keys:function(){return o},entries:function(){return u},get:function(e){return i[e.toLowerCase()]},has:function(e){return e.toLowerCase()in i}}}};for(var l in s.open(n.method||"get",e,!0),s.onload=function(){s.getAllResponseHeaders().replace(/^(.*?):[^\S\n]*([\s\S]*?)$/gm,function(e,n,t){o.push(n=n.toLowerCase()),u.push([n,t]),i[n]=i[n]?i[n]+","+t:t}),t(a())},s.onerror=r,s.withCredentials="include"==n.credentials,n.headers)s.setRequestHeader(l,n.headers[l]);s.send(n.body||null)})}
++}
+diff --git a/node_modules/unfetch/dist/unfetch.mjs.map b/node_modules/unfetch/dist/unfetch.mjs.map
+deleted file mode 100644
+index 658823a..0000000
+--- a/node_modules/unfetch/dist/unfetch.mjs.map
++++ /dev/null
+@@ -1 +0,0 @@
+-{"version":3,"file":"unfetch.mjs","sources":["../src/index.mjs"],"sourcesContent":["export default function(url, options) {\n\toptions = options || {};\n\treturn new Promise( (resolve, reject) => {\n\t\tconst request = new XMLHttpRequest();\n\t\tconst keys = [];\n\t\tconst all = [];\n\t\tconst headers = {};\n\n\t\tconst response = () => ({\n\t\t\tok: (request.status/100|0) == 2,\t\t// 200-299\n\t\t\tstatusText: request.statusText,\n\t\t\tstatus: request.status,\n\t\t\turl: request.responseURL,\n\t\t\ttext: () => Promise.resolve(request.responseText),\n\t\t\tjson: () => Promise.resolve(JSON.parse(request.responseText)),\n\t\t\tblob: () => Promise.resolve(new Blob([request.response])),\n\t\t\tclone: response,\n\t\t\theaders: {\n\t\t\t\tkeys: () => keys,\n\t\t\t\tentries: () => all,\n\t\t\t\tget: n => headers[n.toLowerCase()],\n\t\t\t\thas: n => n.toLowerCase() in headers\n\t\t\t}\n\t\t});\n\n\t\trequest.open(options.method || 'get', url, true);\n\n\t\trequest.onload = () => {\n\t\t\trequest.getAllResponseHeaders().replace(/^(.*?):[^\\S\\n]*([\\s\\S]*?)$/gm, (m, key, value) => {\n\t\t\t\tkeys.push(key = key.toLowerCase());\n\t\t\t\tall.push([key, value]);\n\t\t\t\theaders[key] = headers[key] ? `${headers[key]},${value}` : value;\n\t\t\t});\n\t\t\tresolve(response());\n\t\t};\n\n\t\trequest.onerror = reject;\n\n\t\trequest.withCredentials = options.credentials=='include';\n\n\t\tfor (const i in options.headers) {\n\t\t\trequest.setRequestHeader(i, options.headers[i]);\n\t\t}\n\n\t\trequest.send(options.body || null);\n\t});\n}\n"],"names":["url","options","Promise","resolve","reject","request","XMLHttpRequest","keys","all","headers","response","ok","status","statusText","responseURL","text","responseText","json","JSON","parse","blob","Blob","clone","entries","get","n","toLowerCase","has","const","i","open","method","onload","getAllResponseHeaders","replace","m","key","value","push","onerror","withCredentials","credentials","setRequestHeader","send","body"],"mappings":"eAAe,SAASA,EAAKC,UAC5BA,EAAUA,GAAW,GACd,IAAIC,iBAAUC,EAASC,OACvBC,EAAU,IAAIC,eACdC,EAAO,GACPC,EAAM,GACNC,EAAU,GAEVC,oBACLC,GAA8B,IAAzBN,EAAQO,OAAO,IAAI,GACxBC,WAAYR,EAAQQ,WACpBD,OAAQP,EAAQO,OAChBZ,IAAKK,EAAQS,YACbC,uBAAYb,QAAQC,QAAQE,EAAQW,eACpCC,uBAAYf,QAAQC,QAAQe,KAAKC,MAAMd,EAAQW,gBAC/CI,uBAAYlB,QAAQC,QAAQ,IAAIkB,KAAK,CAAChB,EAAQK,aAC9CY,MAAOZ,EACPD,QAAS,CACRF,uBAAYA,GACZgB,0BAAef,GACfgB,aAAKC,UAAKhB,EAAQgB,EAAEC,gBACpBC,aAAKF,UAAKA,EAAEC,gBAAiBjB,UAmB1BmB,IAAMC,KAfXxB,EAAQyB,KAAK7B,EAAQ8B,QAAU,MAAO/B,GAAK,GAE3CK,EAAQ2B,kBACP3B,EAAQ4B,wBAAwBC,QAAQ,wCAAiCC,EAAGC,EAAKC,GAChF9B,EAAK+B,KAAKF,EAAMA,EAAIV,eACpBlB,EAAI8B,KAAK,CAACF,EAAKC,IACf5B,EAAQ2B,GAAO3B,EAAQ2B,GAAU3B,EAAQ2B,OAAQC,EAAUA,IAE5DlC,EAAQO,MAGTL,EAAQkC,QAAUnC,EAElBC,EAAQmC,gBAAuC,WAArBvC,EAAQwC,YAElBxC,EAAQQ,QACvBJ,EAAQqC,iBAAiBb,EAAG5B,EAAQQ,QAAQoB,IAG7CxB,EAAQsC,KAAK1C,EAAQ2C,MAAQ"}
+\ No newline at end of file
+diff --git a/node_modules/unfetch/dist/unfetch.umd.js b/node_modules/unfetch/dist/unfetch.umd.js
+deleted file mode 100644
+index cdab30c..0000000
+--- a/node_modules/unfetch/dist/unfetch.umd.js
++++ /dev/null
+@@ -1,2 +0,0 @@
+-!function(e,n){"object"==typeof exports&&"undefined"!=typeof module?module.exports=n():"function"==typeof define&&define.amd?define(n):e.unfetch=n()}(this,function(){return function(e,n){return n=n||{},new Promise(function(t,o){var r=new XMLHttpRequest,s=[],u=[],i={},f=function(){return{ok:2==(r.status/100|0),statusText:r.statusText,status:r.status,url:r.responseURL,text:function(){return Promise.resolve(r.responseText)},json:function(){return Promise.resolve(JSON.parse(r.responseText))},blob:function(){return Promise.resolve(new Blob([r.response]))},clone:f,headers:{keys:function(){return s},entries:function(){return u},get:function(e){return i[e.toLowerCase()]},has:function(e){return e.toLowerCase()in i}}}};for(var a in r.open(n.method||"get",e,!0),r.onload=function(){r.getAllResponseHeaders().replace(/^(.*?):[^\S\n]*([\s\S]*?)$/gm,function(e,n,t){s.push(n=n.toLowerCase()),u.push([n,t]),i[n]=i[n]?i[n]+","+t:t}),t(f())},r.onerror=o,r.withCredentials="include"==n.credentials,n.headers)r.setRequestHeader(a,n.headers[a]);r.send(n.body||null)})}});
+-//# sourceMappingURL=unfetch.umd.js.map
+diff --git a/node_modules/unfetch/dist/unfetch.umd.js.map b/node_modules/unfetch/dist/unfetch.umd.js.map
+deleted file mode 100644
+index 57a2761..0000000
+--- a/node_modules/unfetch/dist/unfetch.umd.js.map
++++ /dev/null
+@@ -1 +0,0 @@
+-{"version":3,"file":"unfetch.umd.js","sources":["../src/index.mjs"],"sourcesContent":["export default function(url, options) {\n\toptions = options || {};\n\treturn new Promise( (resolve, reject) => {\n\t\tconst request = new XMLHttpRequest();\n\t\tconst keys = [];\n\t\tconst all = [];\n\t\tconst headers = {};\n\n\t\tconst response = () => ({\n\t\t\tok: (request.status/100|0) == 2,\t\t// 200-299\n\t\t\tstatusText: request.statusText,\n\t\t\tstatus: request.status,\n\t\t\turl: request.responseURL,\n\t\t\ttext: () => Promise.resolve(request.responseText),\n\t\t\tjson: () => Promise.resolve(JSON.parse(request.responseText)),\n\t\t\tblob: () => Promise.resolve(new Blob([request.response])),\n\t\t\tclone: response,\n\t\t\theaders: {\n\t\t\t\tkeys: () => keys,\n\t\t\t\tentries: () => all,\n\t\t\t\tget: n => headers[n.toLowerCase()],\n\t\t\t\thas: n => n.toLowerCase() in headers\n\t\t\t}\n\t\t});\n\n\t\trequest.open(options.method || 'get', url, true);\n\n\t\trequest.onload = () => {\n\t\t\trequest.getAllResponseHeaders().replace(/^(.*?):[^\\S\\n]*([\\s\\S]*?)$/gm, (m, key, value) => {\n\t\t\t\tkeys.push(key = key.toLowerCase());\n\t\t\t\tall.push([key, value]);\n\t\t\t\theaders[key] = headers[key] ? `${headers[key]},${value}` : value;\n\t\t\t});\n\t\t\tresolve(response());\n\t\t};\n\n\t\trequest.onerror = reject;\n\n\t\trequest.withCredentials = options.credentials=='include';\n\n\t\tfor (const i in options.headers) {\n\t\t\trequest.setRequestHeader(i, options.headers[i]);\n\t\t}\n\n\t\trequest.send(options.body || null);\n\t});\n}\n"],"names":["url","options","Promise","resolve","reject","request","XMLHttpRequest","keys","all","headers","response","ok","status","statusText","responseURL","text","responseText","json","JSON","parse","blob","Blob","clone","entries","get","n","toLowerCase","has","const","i","open","method","onload","getAllResponseHeaders","replace","m","key","value","push","onerror","withCredentials","credentials","setRequestHeader","send","body"],"mappings":"6KAAe,SAASA,EAAKC,UAC5BA,EAAUA,GAAW,GACd,IAAIC,iBAAUC,EAASC,OACvBC,EAAU,IAAIC,eACdC,EAAO,GACPC,EAAM,GACNC,EAAU,GAEVC,oBACLC,GAA8B,IAAzBN,EAAQO,OAAO,IAAI,GACxBC,WAAYR,EAAQQ,WACpBD,OAAQP,EAAQO,OAChBZ,IAAKK,EAAQS,YACbC,uBAAYb,QAAQC,QAAQE,EAAQW,eACpCC,uBAAYf,QAAQC,QAAQe,KAAKC,MAAMd,EAAQW,gBAC/CI,uBAAYlB,QAAQC,QAAQ,IAAIkB,KAAK,CAAChB,EAAQK,aAC9CY,MAAOZ,EACPD,QAAS,CACRF,uBAAYA,GACZgB,0BAAef,GACfgB,aAAKC,UAAKhB,EAAQgB,EAAEC,gBACpBC,aAAKF,UAAKA,EAAEC,gBAAiBjB,UAmB1BmB,IAAMC,KAfXxB,EAAQyB,KAAK7B,EAAQ8B,QAAU,MAAO/B,GAAK,GAE3CK,EAAQ2B,kBACP3B,EAAQ4B,wBAAwBC,QAAQ,wCAAiCC,EAAGC,EAAKC,GAChF9B,EAAK+B,KAAKF,EAAMA,EAAIV,eACpBlB,EAAI8B,KAAK,CAACF,EAAKC,IACf5B,EAAQ2B,GAAO3B,EAAQ2B,GAAU3B,EAAQ2B,OAAQC,EAAUA,IAE5DlC,EAAQO,MAGTL,EAAQkC,QAAUnC,EAElBC,EAAQmC,gBAAuC,WAArBvC,EAAQwC,YAElBxC,EAAQQ,QACvBJ,EAAQqC,iBAAiBb,EAAG5B,EAAQQ,QAAQoB,IAG7CxB,EAAQsC,KAAK1C,EAAQ2C,MAAQ"}
+\ No newline at end of file
+diff --git a/node_modules/unfetch/src/index.mjs b/node_modules/unfetch/src/index.mjs
+deleted file mode 100644
+index 783ad42..0000000
+--- a/node_modules/unfetch/src/index.mjs
++++ /dev/null
+@@ -1,47 +0,0 @@
+-export default function(url, options) {
+-	options = options || {};
+-	return new Promise( (resolve, reject) => {
+-		const request = new XMLHttpRequest();
+-		const keys = [];
+-		const all = [];
+-		const headers = {};
+-
+-		const response = () => ({
+-			ok: (request.status/100|0) == 2,		// 200-299
+-			statusText: request.statusText,
+-			status: request.status,
+-			url: request.responseURL,
+-			text: () => Promise.resolve(request.responseText),
+-			json: () => Promise.resolve(JSON.parse(request.responseText)),
+-			blob: () => Promise.resolve(new Blob([request.response])),
+-			clone: response,
+-			headers: {
+-				keys: () => keys,
+-				entries: () => all,
+-				get: n => headers[n.toLowerCase()],
+-				has: n => n.toLowerCase() in headers
+-			}
+-		});
+-
+-		request.open(options.method || 'get', url, true);
+-
+-		request.onload = () => {
+-			request.getAllResponseHeaders().replace(/^(.*?):[^\S\n]*([\s\S]*?)$/gm, (m, key, value) => {
+-				keys.push(key = key.toLowerCase());
+-				all.push([key, value]);
+-				headers[key] = headers[key] ? `${headers[key]},${value}` : value;
+-			});
+-			resolve(response());
+-		};
+-
+-		request.onerror = reject;
+-
+-		request.withCredentials = options.credentials=='include';
+-
+-		for (const i in options.headers) {
+-			request.setRequestHeader(i, options.headers[i]);
+-		}
+-
+-		request.send(options.body || null);
+-	});
+-}
diff --git a/packages/driver/src/cypress/cy.js b/packages/driver/src/cypress/cy.js
index 838b2f844bb..03356360dbf 100644
--- a/packages/driver/src/cypress/cy.js
+++ b/packages/driver/src/cypress/cy.js
@@ -31,6 +31,8 @@ const $CommandQueue = require('./command_queue')
 const $VideoRecorder = require('../cy/video-recorder')
 const $TestConfigOverrides = require('../cy/testConfigOverrides')
 
+const { registerFetch } = require('unfetch')
+
 const privateProps = {
   props: { name: 'state', url: true },
   privates: { name: 'state', url: false },
@@ -258,6 +260,14 @@ const create = function (specWindow, Cypress, Cookies, state, config, log) {
 
       contentWindow.CSSStyleSheet.prototype.insertRule = _.wrap(insertRule, cssModificationSpy)
       contentWindow.CSSStyleSheet.prototype.deleteRule = _.wrap(deleteRule, cssModificationSpy)
+
+      if (config('experimentalFetchPolyfill')) {
+        // drop "fetch" polyfill that replaces it with XMLHttpRequest
+        // from the app iframe that we wrap for network stubbing
+        contentWindow.fetch = registerFetch(contentWindow)
+        // flag the polyfill to test this experimental feature easier
+        state('fetchPolyfilled', true)
+      }
     } catch (error) {} // eslint-disable-line no-empty
   }
 
diff --git a/packages/server/lib/config.js b/packages/server/lib/config.js
index e0dd5d38bbb..8c674634a79 100644
--- a/packages/server/lib/config.js
+++ b/packages/server/lib/config.js
@@ -104,7 +104,13 @@ browsers\
 // Know experimental flags / values
 // each should start with "experimental" and be camel cased
 // example: experimentalComponentTesting
-const experimentalConfigKeys = ['experimentalGetCookiesSameSite', 'experimentalSourceRewriting', 'experimentalComponentTesting', 'experimentalShadowDomSupport']
+const experimentalConfigKeys = toWords(`\
+experimentalGetCookiesSameSite
+experimentalSourceRewriting
+experimentalComponentTesting
+experimentalShadowDomSupport
+experimentalFetchPolyfill\
+`)
 
 const CONFIG_DEFAULTS = {
   port: null,
@@ -171,6 +177,7 @@ const CONFIG_DEFAULTS = {
   experimentalGetCookiesSameSite: false,
   experimentalSourceRewriting: false,
   experimentalShadowDomSupport: false,
+  experimentalFetchPolyfill: false,
 }
 
 const validationRules = {
@@ -218,6 +225,7 @@ const validationRules = {
   experimentalGetCookiesSameSite: v.isBoolean,
   experimentalSourceRewriting: v.isBoolean,
   experimentalShadowDomSupport: v.isBoolean,
+  experimentalFetchPolyfill: v.isBoolean,
 }
 
 const convertRelativeToAbsolutePaths = (projectRoot, obj, defaults = {}) => {
diff --git a/packages/server/lib/experiments.ts b/packages/server/lib/experiments.ts
index c9a8859bebf..610bf5d194e 100644
--- a/packages/server/lib/experiments.ts
+++ b/packages/server/lib/experiments.ts
@@ -54,6 +54,7 @@ const _summaries: StringValues = {
   experimentalComponentTesting: 'Framework-specific component testing, uses `componentFolder` to load component specs',
   experimentalSourceRewriting: 'Enables AST-based JS/HTML rewriting. This may fix issues caused by the existing regex-based JS/HTML replacement algorithm.',
   experimentalGetCookiesSameSite: 'Adds `sameSite` values to the objects yielded from `cy.setCookie()`, `cy.getCookie()`, and `cy.getCookies()`. This will become the default behavior in Cypress 5.0.',
+  experimentalFetchPolyfill: 'Polyfills `window.fetch` to enable Network spying and stubbing',
   experimentalShadowDomSupport: 'Enables support for shadow DOM traversal, introduces the `shadow()` command and the `includeShadowDom` option to traversal commands.',
 }
 
@@ -72,6 +73,7 @@ const _names: StringValues = {
   experimentalSourceRewriting: 'Improved source rewriting',
   experimentalGetCookiesSameSite: 'Set `sameSite` property when retrieving cookies',
   experimentalShadowDomSupport: 'Shadow DOM Support',
+  experimentalFetchPolyfill: 'Fetch polyfill',
 }
 
 /**
diff --git a/packages/server/test/e2e/8_fetch_polyfill_spec.js b/packages/server/test/e2e/8_fetch_polyfill_spec.js
new file mode 100644
index 00000000000..ec329330d44
--- /dev/null
+++ b/packages/server/test/e2e/8_fetch_polyfill_spec.js
@@ -0,0 +1,162 @@
+const e2e = require('../support/helpers/e2e').default
+const { stripIndent } = require('common-tags')
+const bodyParser = require('body-parser')
+
+const onServer = function (app) {
+  app.use(bodyParser.json({ extended: false }))
+
+  app.get('/get-json', (req, res) => {
+    return res.json([1, 2, 3])
+  })
+
+  app.get('/get-text', (req, res) => {
+    return res.send('pong')
+  })
+
+  app.post('/add', (req, res) => {
+    if (req.body.method !== 'add') {
+      throw new Error('wrong body method')
+    }
+
+    return res.json({ answer: req.body.a + req.body.b })
+  })
+
+  // page posts a JSON object
+  app.get('/addition', (req, res) => {
+    return res.send(stripIndent`
+      <body>
+        <div id="result"></div>
+        <script>
+          const data = {
+            method: 'add',
+            a: 2,
+            b: 15
+          }
+          fetch('/add', {
+            method: 'POST',
+            headers: {
+              'Content-Type': 'application/json'
+            },
+            body: JSON.stringify(data)
+          }).then((response) => {
+            if (!response) {
+              throw new Error('no response')
+            }
+            if (!response.ok) {
+              throw new Error('response is not ok')
+            }
+            return response.json()
+          }).then(j => {
+            // either answer from the server
+            // or from the network stub
+            if (j.answer !== 17 && j.answer !== 193) {
+              throw new Error('wrong answer')
+            }
+            document.getElementById('result').innerText = 'answer: ' + j.answer
+          })
+        </script>
+      </body>
+    `)
+  })
+
+  // page fetches JSON array
+  app.get('/first', (req, res) => {
+    return res.send(stripIndent`
+      <body>
+        <script>
+          fetch('/get-json')
+          .then((response) => {
+            if (!response) {
+              throw new Error('no response')
+            }
+            if (!response.ok) {
+              throw new Error('response is not ok')
+            }
+            return response.json()
+          })
+          .then((list) => {
+            if (list.length !== 3) {
+              throw new Error('Wrong number of items')
+            }
+            if (list[0] !== 1) {
+              throw new Error('Wrong first item')
+            }
+            if (list[1] !== 2) {
+              throw new Error('Wrong second item')
+            }
+            if (list[2] !== 3) {
+              throw new Error('Wrong third item')
+            }
+          })
+        </script>
+        <a href="/second">second</a>
+      </body>
+    `)
+  })
+
+  // page fetches text
+  app.get('/second', (req, res) => {
+    return res.send(stripIndent`
+      <body>
+        <div id="result"></div>
+        <script>
+          fetch('/get-text')
+          .then((response) => {
+            if (!response) {
+              throw new Error('no response')
+            }
+            if (!response.ok) {
+              throw new Error('response is not ok')
+            }
+            if (response.status !== 200) {
+              throw new Error('response status not 200')
+            }
+            return response.text()
+          })
+          .then((text) => {
+            // allow response from the server
+            // or stub response
+            if (text !== 'pong' && text !== 'mock pong') {
+              throw new Error('Wrong text response')
+            }
+            document.getElementById('result').innerText = 'text: ' + text
+          })
+        </script>
+      </body>
+    `)
+  })
+}
+
+describe('e2e fetch polyfill', () => {
+  e2e.setup({
+    servers: {
+      port: 1818,
+      onServer,
+    },
+  })
+
+  e2e.it('passes', {
+    spec: 'fetch_spec.coffee',
+    snapshot: false,
+    config: {
+      experimentalFetchPolyfill: true,
+    },
+  })
+})
+
+describe('e2e no fetch polyfill', () => {
+  e2e.setup({
+    servers: {
+      port: 1818,
+      onServer,
+    },
+  })
+
+  e2e.it('passes', {
+    spec: 'fetch_no_polyfill_spec.coffee',
+    snapshot: false,
+    config: {
+      experimentalFetchPolyfill: false,
+    },
+  })
+})
diff --git a/packages/server/test/support/fixtures/projects/e2e/cypress/integration/fetch_no_polyfill_spec.coffee b/packages/server/test/support/fixtures/projects/e2e/cypress/integration/fetch_no_polyfill_spec.coffee
new file mode 100644
index 00000000000..578baa4c428
--- /dev/null
+++ b/packages/server/test/support/fixtures/projects/e2e/cypress/integration/fetch_no_polyfill_spec.coffee
@@ -0,0 +1,5 @@
+describe "without fetch polyfill", ->
+  it "does not set polyfilled state", ->
+    cy.visit("http://localhost:1818/first")
+      .then ->
+        expect(cy.state("fetchPolyfilled")).to.be.undefined
diff --git a/packages/server/test/support/fixtures/projects/e2e/cypress/integration/fetch_spec.coffee b/packages/server/test/support/fixtures/projects/e2e/cypress/integration/fetch_spec.coffee
new file mode 100644
index 00000000000..e78158c11e9
--- /dev/null
+++ b/packages/server/test/support/fixtures/projects/e2e/cypress/integration/fetch_spec.coffee
@@ -0,0 +1,44 @@
+describe "fetch works", ->
+  it "sets polyfilled state", ->
+    cy.visit("http://localhost:1818/first")
+      .then ->
+        expect(cy.state("fetchPolyfilled")).to.be.true
+
+  it "spies on fetch requests", ->
+    cy.server()
+    cy.route("/get-json").as("get-json")
+    cy.visit("http://localhost:1818/first")
+    cy.wait("@get-json")
+
+  it "spies on fetch requests from second page", ->
+    cy.server()
+    cy.route("/get-text").as("get-text")
+    cy.visit("http://localhost:1818/first")
+    cy.contains("a", "second").click()
+    cy.wait("@get-text")
+    # confirm the real response from the server is shown
+    cy.contains("text: pong").should("be.visible")
+
+  it "stubs GET fetch text", ->
+    cy.server()
+    cy.route("/get-text", "mock pong")
+    cy.visit("http://localhost:1818/second")
+    # confirm the stub response is shown
+    cy.contains("text: mock pong").should("be.visible")
+
+  it "spies on fetch POST", ->
+    cy.server()
+    cy.route("POST", "/add").as("add")
+    cy.visit("http://localhost:1818/addition")
+    cy.wait("@add")
+    # confirm the response from the server is displayed
+    cy.contains("answer: 17").should('be.visible')
+
+  it "stubs fetch POST", ->
+    cy.server()
+    cy.route("POST", "/add", {answer: 193}).as("add")
+    cy.visit("http://localhost:1818/addition")
+    cy.wait("@add")
+    # confirm the stub was used
+    cy.contains("answer: 193").should('be.visible')
+
diff --git a/packages/server/test/unit/config_spec.js b/packages/server/test/unit/config_spec.js
index 9defaf13848..9c821ccb04d 100644
--- a/packages/server/test/unit/config_spec.js
+++ b/packages/server/test/unit/config_spec.js
@@ -1137,6 +1137,7 @@ describe('lib/config', () => {
             experimentalComponentTesting: { value: false, from: 'default' },
             componentFolder: { value: 'cypress/component', from: 'default' },
             experimentalShadowDomSupport: { value: false, from: 'default' },
+            experimentalFetchPolyfill: { value: false, from: 'default' },
           })
         })
       })
@@ -1213,6 +1214,7 @@ describe('lib/config', () => {
             experimentalComponentTesting: { value: false, from: 'default' },
             componentFolder: { value: 'cypress/component', from: 'default' },
             experimentalShadowDomSupport: { value: false, from: 'default' },
+            experimentalFetchPolyfill: { value: false, from: 'default' },
             env: {
               foo: {
                 value: 'foo',
diff --git a/yarn.lock b/yarn.lock
index c0705e8e814..53322a2af30 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -24631,6 +24631,11 @@ undertaker@^1.2.1:
     object.reduce "^1.0.0"
     undertaker-registry "^1.0.0"
 
+unfetch@4.1.0:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/unfetch/-/unfetch-4.1.0.tgz#6ec2dd0de887e58a4dee83a050ded80ffc4137db"
+  integrity sha512-crP/n3eAPUJxZXM9T80/yv0YhkTEx2K1D3h7D1AJM6fzsWZrxdyRuLN0JH/dkZh1LNH8LxCnBzoPFCPbb2iGpg==
+
 unicode-canonical-property-names-ecmascript@^1.0.4:
   version "1.0.4"
   resolved "https://registry.yarnpkg.com/unicode-canonical-property-names-ecmascript/-/unicode-canonical-property-names-ecmascript-1.0.4.tgz#2619800c4c825800efdd8343af7dd9933cbe2818"