diff --git a/Changelog.md b/Changelog.md
index e5c0d8b9cd..38c642d6d2 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -13,6 +13,9 @@
 - The result of a mutation is now made available to the wrapped component, 
   when using the `graphql` HOC.  <br/>
   [@andycarrell](https://github.com/andycarrell) in [#3008](https://github.com/apollographql/react-apollo/pull/3008) 
+- Check equality of stringified variables in the `MockLink` to improve
+  debugging experience used by `MockedProvider`.  <br/>
+  [@evans](https://github.com/evans) in [#3078](https://github.com/apollographql/react-apollo/pull/3078)
 
 ### Bug Fixes
 
diff --git a/package-lock.json b/package-lock.json
index 3db54b89b4..9ffa393d77 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -942,6 +942,12 @@
       "integrity": "sha512-EYNwp3bU+98cpU4lAWYYL7Zz+2gryWH1qbdDTidVd6hkiR6weksdbMadyXKXNPEkQFhXM+hVO9ZygomHXp+AIw==",
       "dev": true
     },
+    "@types/fast-json-stable-stringify": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/@types/fast-json-stable-stringify/-/fast-json-stable-stringify-2.0.0.tgz",
+      "integrity": "sha512-mky/O83TXmGY39P1H9YbUpjV6l6voRYlufqfFCvel8l1phuy8HRjdWc1rrPuN53ITBJlbyMSV6z3niOySO5pgQ==",
+      "dev": true
+    },
     "@types/graphql": {
       "version": "14.2.0",
       "resolved": "https://registry.npmjs.org/@types/graphql/-/graphql-14.2.0.tgz",
@@ -3261,7 +3267,7 @@
         },
         "minimist": {
           "version": "1.2.0",
-          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "resolved": "http://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
           "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
           "dev": true
         },
@@ -3705,7 +3711,7 @@
     },
     "es6-promisify": {
       "version": "5.0.0",
-      "resolved": "https://registry.npmjs.org/es6-promisify/-/es6-promisify-5.0.0.tgz",
+      "resolved": "http://registry.npmjs.org/es6-promisify/-/es6-promisify-5.0.0.tgz",
       "integrity": "sha1-UQnWLz5W6pZ8S2NQWu8IKRyKUgM=",
       "dev": true,
       "requires": {
@@ -4182,8 +4188,7 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -4204,14 +4209,12 @@
         "balanced-match": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "brace-expansion": {
           "version": "1.1.11",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "balanced-match": "^1.0.0",
             "concat-map": "0.0.1"
@@ -4226,20 +4229,17 @@
         "code-point-at": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "concat-map": {
           "version": "0.0.1",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "console-control-strings": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "core-util-is": {
           "version": "1.0.2",
@@ -4356,8 +4356,7 @@
         "inherits": {
           "version": "2.0.3",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "ini": {
           "version": "1.3.5",
@@ -4369,7 +4368,6 @@
           "version": "1.0.0",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "number-is-nan": "^1.0.0"
           }
@@ -4384,7 +4382,6 @@
           "version": "3.0.4",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "brace-expansion": "^1.1.7"
           }
@@ -4392,14 +4389,12 @@
         "minimist": {
           "version": "0.0.8",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "minipass": {
           "version": "2.3.5",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "safe-buffer": "^5.1.2",
             "yallist": "^3.0.0"
@@ -4418,7 +4413,6 @@
           "version": "0.5.1",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "minimist": "0.0.8"
           }
@@ -4499,8 +4493,7 @@
         "number-is-nan": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "object-assign": {
           "version": "4.1.1",
@@ -4512,7 +4505,6 @@
           "version": "1.4.0",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "wrappy": "1"
           }
@@ -4598,8 +4590,7 @@
         "safe-buffer": {
           "version": "5.1.2",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -4635,7 +4626,6 @@
           "version": "1.0.2",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "code-point-at": "^1.0.0",
             "is-fullwidth-code-point": "^1.0.0",
@@ -4655,7 +4645,6 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -4699,14 +4688,12 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         },
         "yallist": {
           "version": "3.0.3",
           "bundled": true,
-          "dev": true,
-          "optional": true
+          "dev": true
         }
       }
     },
@@ -10487,7 +10474,7 @@
         },
         "minimist": {
           "version": "1.2.0",
-          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "resolved": "http://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
           "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
           "dev": true
         },
diff --git a/package.json b/package.json
index 25c03530be..d1f2ecb200 100644
--- a/package.json
+++ b/package.json
@@ -109,6 +109,7 @@
   "devDependencies": {
     "@types/enzyme": "3.9.3",
     "@types/enzyme-adapter-react-16": "1.0.5",
+    "@types/fast-json-stable-stringify": "^2.0.0",
     "@types/graphql": "14.2.0",
     "@types/hoist-non-react-statics": "3.3.1",
     "@types/invariant": "2.2.29",
@@ -165,6 +166,7 @@
   },
   "dependencies": {
     "apollo-utilities": "^1.3.0",
+    "fast-json-stable-stringify": "^2.0.0",
     "hoist-non-react-statics": "^3.3.0",
     "lodash.isequal": "^4.5.0",
     "prop-types": "^15.7.2",
diff --git a/src/test-links.ts b/src/test-links.ts
index d7e48b2b94..ec1148b210 100644
--- a/src/test-links.ts
+++ b/src/test-links.ts
@@ -6,6 +6,7 @@ import {
   Observable,
   // Observer,
 } from 'apollo-link';
+import stringify from 'fast-json-stable-stringify';
 
 import { print } from 'graphql/language/printer';
 import {
@@ -67,7 +68,7 @@ export class MockLink extends ApolloLink {
     const response = (this.mockedResponsesByKey[key] || []).find((res, index) => {
       const requestVariables = operation.variables || {};
       const mockedResponseVariables = res.request.variables || {};
-      if (!isEqual(requestVariables, mockedResponseVariables)) {
+      if (!isEqual(stringify(requestVariables), stringify(mockedResponseVariables))) {
         return false;
       }
       responseIndex = index;