diff --git a/CHANGELOG.md b/CHANGELOG.md
index 250c686ddbd..62e60d7d7fc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,11 +20,14 @@
 - Make sure the `MockedResponse` `ResultFunction` type is re-exported.  <br/>
   [@hwillson](https://github.com/hwillson) in [#8315](https://github.com/apollographql/apollo-client/pull/8315)
 
-### Potentially breaking changes
+### Potentially disruptive changes
 
 - To avoid retaining sensitive information from mutation root field arguments, Apollo Client v3.4 automatically clears any `ROOT_MUTATION` fields from the cache after each mutation finishes. If you need this information to remain in the cache, you can prevent the removal by passing the `keepRootFields: true` option to `client.mutate`. `ROOT_MUTATION` result data are also passed to the mutation `update` function, so we recommend obtaining the results that way, rather than using `keepRootFields: true`, if possible. <br/>
   [@benjamn](https://github.com/benjamn) in [#8280](https://github.com/apollographql/apollo-client/pull/8280)
 
+- Internally, Apollo Client now controls the execution of development-only code using the `__DEV__` global variable, rather than `process.env.NODE_ENV`. While this change should not cause any visible differences in behavior, it will increase your minified+gzip bundle size by more than 3.5kB, unless you configure your minifier to replace `__DEV__` with a `true` or `false` constant, the same way you already replace `process.env.NODE_ENV` with a string literal like `"development"` or `"production"`. For an example of configuring a Create React App project without ejecting, see this pull request for our [React Apollo reproduction template](https://github.com/apollographql/react-apollo-error-template/pull/51). <br/>
+  [@benjamn](https://github.com/benjamn) in [#8347](https://github.com/apollographql/apollo-client/pull/8347)
+
 - Internally, Apollo Client now uses namespace syntax (e.g. `import * as React from "react"`) for imports whose types are re-exported (and thus may appear in `.d.ts` files). This change should remove any need to configure `esModuleInterop` or `allowSyntheticDefaultImports` in `tsconfig.json`, but might require updating bundler configurations that specify named exports of the `react` and `prop-types` packages, to include exports like `createContext` and `createElement` ([example](https://github.com/apollographql/apollo-client/commit/16b08e1af9ba9934041298496e167aafb128c15d)). <br/>
   [@devrelm](https://github.com/devrelm) in [#7742](https://github.com/apollographql/apollo-client/pull/7742)
 
diff --git a/config/processInvariants.ts b/config/processInvariants.ts
index c719d5b71bf..0a26a01e9ee 100644
--- a/config/processInvariants.ts
+++ b/config/processInvariants.ts
@@ -71,7 +71,7 @@ function transform(code: string, file: string) {
       const node = path.node;
 
       if (isCallWithLength(node, "invariant", 1)) {
-        if (isNodeEnvConditional(path.parent.node)) {
+        if (isDEVConditional(path.parent.node)) {
           return;
         }
 
@@ -79,22 +79,22 @@ function transform(code: string, file: string) {
         newArgs.push(getErrorCode(file, node));
 
         return b.conditionalExpression(
-          makeNodeEnvTest(),
+          makeDEVExpr(),
+          node,
           b.callExpression.from({
             ...node,
             arguments: newArgs,
           }),
-          node,
         );
       }
 
       if (node.callee.type === "MemberExpression" &&
           isIdWithName(node.callee.object, "invariant") &&
           isIdWithName(node.callee.property, "log", "warn", "error")) {
-        if (isNodeEnvLogicalOr(path.parent.node)) {
+        if (isDEVLogicalAnd(path.parent.node)) {
           return;
         }
-        return b.logicalExpression("||", makeNodeEnvTest(), node);
+        return b.logicalExpression("&&", makeDEVExpr(), node);
       }
     },
 
@@ -102,19 +102,19 @@ function transform(code: string, file: string) {
       this.traverse(path);
       const node = path.node;
       if (isCallWithLength(node, "InvariantError", 0)) {
-        if (isNodeEnvConditional(path.parent.node)) {
+        if (isDEVConditional(path.parent.node)) {
           return;
         }
 
         const newArgs = [getErrorCode(file, node)];
 
         return b.conditionalExpression(
-          makeNodeEnvTest(),
+          makeDEVExpr(),
+          node,
           b.newExpression.from({
             ...node,
             arguments: newArgs,
           }),
-          node,
         );
       }
     }
@@ -137,32 +137,21 @@ function isCallWithLength(
     node.arguments.length > length;
 }
 
-function isNodeEnvConditional(node: Node) {
+function isDEVConditional(node: Node) {
   return n.ConditionalExpression.check(node) &&
-    isNodeEnvExpr(node.test);
+    isDEVExpr(node.test);
 }
 
-function isNodeEnvLogicalOr(node: Node) {
+function isDEVLogicalAnd(node: Node) {
   return n.LogicalExpression.check(node) &&
-    node.operator === "||" &&
-    isNodeEnvExpr(node.left);
+    node.operator === "&&" &&
+    isDEVExpr(node.left);
 }
 
-function makeNodeEnvTest() {
-  return b.binaryExpression(
-    "===",
-    b.memberExpression(
-      b.memberExpression(
-        b.identifier("process"),
-        b.identifier("env")
-      ),
-      b.identifier("NODE_ENV"),
-    ),
-    b.stringLiteral("production"),
-  );
+function makeDEVExpr() {
+  return b.identifier("__DEV__");
 }
 
-const referenceNodeEnvExpr = makeNodeEnvTest();
-function isNodeEnvExpr(node: Node) {
-  return recast.types.astNodesAreEquivalent(node, referenceNodeEnvExpr);
+function isDEVExpr(node: Node) {
+  return isIdWithName(node, "__DEV__");
 }
diff --git a/config/rollup.config.js b/config/rollup.config.js
index abe73fabcd2..511c832acfc 100644
--- a/config/rollup.config.js
+++ b/config/rollup.config.js
@@ -71,7 +71,7 @@ function prepareCJSMinified(input) {
         compress: {
           toplevel: true,
           global_defs: {
-            '@process.env.NODE_ENV': JSON.stringify('production'),
+            '@__DEV__': 'false',
           },
         },
       }),
@@ -97,27 +97,6 @@ function prepareBundle({
       exports: 'named',
       interop: 'esModule',
       externalLiveBindings: false,
-      // In Node.js, where these CommonJS bundles are most commonly used,
-      // the expression process.env.NODE_ENV can be very expensive to
-      // evaluate, because process.env is a wrapper for the actual OS
-      // environment, and lookups are not cached. We need to preserve the
-      // syntax of process.env.NODE_ENV expressions for dead code
-      // elimination to work properly, but we can apply our own caching by
-      // shadowing the global process variable with a stripped-down object
-      // that saves a snapshot of process.env.NODE_ENV when the bundle is
-      // first evaluated. If we ever need other process properties, we can
-      // add more stubs here.
-      intro: '!(function (process) {',
-      outro: [
-        '}).call(this, {',
-        '  env: {',
-        '    NODE_ENV: typeof process === "object"',
-        '      && process.env',
-        '      && process.env.NODE_ENV',
-        '      || "development"',
-        '  }',
-        '});',
-      ].join('\n'),
     },
     plugins: [
       extensions ? nodeResolve({ extensions }) : nodeResolve(),
diff --git a/src/__tests__/__snapshots__/exports.ts.snap b/src/__tests__/__snapshots__/exports.ts.snap
index f5acde2fc1e..2f5236a1156 100644
--- a/src/__tests__/__snapshots__/exports.ts.snap
+++ b/src/__tests__/__snapshots__/exports.ts.snap
@@ -16,6 +16,7 @@ Array [
   "NetworkStatus",
   "Observable",
   "ObservableQuery",
+  "__DEV__",
   "checkFetcher",
   "concat",
   "createHttpLink",
@@ -67,6 +68,7 @@ Array [
   "InMemoryCache",
   "MissingFieldError",
   "Policies",
+  "__DEV__",
   "cacheSlot",
   "canonicalStringify",
   "defaultDataIdFromObject",
@@ -90,6 +92,7 @@ Array [
   "NetworkStatus",
   "Observable",
   "ObservableQuery",
+  "__DEV__",
   "checkFetcher",
   "concat",
   "createHttpLink",
@@ -224,6 +227,7 @@ Array [
   "ApolloConsumer",
   "ApolloProvider",
   "DocumentType",
+  "__DEV__",
   "getApolloContext",
   "operationName",
   "parser",
@@ -320,6 +324,7 @@ Array [
   "Concast",
   "DeepMerger",
   "Observable",
+  "__DEV__",
   "addTypenameToDocument",
   "argumentsObjectFromField",
   "asyncMap",
diff --git a/src/cache/index.ts b/src/cache/index.ts
index 5e3f221a44f..220bfdf378a 100644
--- a/src/cache/index.ts
+++ b/src/cache/index.ts
@@ -1,3 +1,5 @@
+export { __DEV__ } from "../utilities";
+
 export { Transaction, ApolloCache } from './core/cache';
 export { Cache } from './core/types/Cache';
 export { DataProxy } from './core/types/DataProxy';
diff --git a/src/cache/inmemory/__tests__/roundtrip.ts b/src/cache/inmemory/__tests__/roundtrip.ts
index 8facc6cbbf5..8604a09a883 100644
--- a/src/cache/inmemory/__tests__/roundtrip.ts
+++ b/src/cache/inmemory/__tests__/roundtrip.ts
@@ -57,7 +57,7 @@ function storeRoundtrip(query: DocumentNode, result: any, variables = {}) {
   const immutableResult = readQueryFromStore(reader, readOptions);
   expect(immutableResult).toEqual(reconstructedResult);
   expect(readQueryFromStore(reader, readOptions)).toBe(immutableResult);
-  if (process.env.NODE_ENV !== 'production') {
+  if (__DEV__) {
     try {
       // Note: this illegal assignment will only throw in strict mode, but that's
       // safe to assume because this test file is a module.
diff --git a/src/cache/inmemory/object-canon.ts b/src/cache/inmemory/object-canon.ts
index e436d74d7dd..22f39b4243d 100644
--- a/src/cache/inmemory/object-canon.ts
+++ b/src/cache/inmemory/object-canon.ts
@@ -118,7 +118,7 @@ export class ObjectCanon {
             // Since canonical arrays may be shared widely between
             // unrelated consumers, it's important to regard them as
             // immutable, even if they are not frozen in production.
-            if (process.env.NODE_ENV !== "production") {
+            if (__DEV__) {
               Object.freeze(array);
             }
           }
@@ -154,7 +154,7 @@ export class ObjectCanon {
             // Since canonical objects may be shared widely between
             // unrelated consumers, it's important to regard them as
             // immutable, even if they are not frozen in production.
-            if (process.env.NODE_ENV !== "production") {
+            if (__DEV__) {
               Object.freeze(obj);
             }
           }
diff --git a/src/cache/inmemory/readFromStore.ts b/src/cache/inmemory/readFromStore.ts
index dbce333b190..7fcfa59b343 100644
--- a/src/cache/inmemory/readFromStore.ts
+++ b/src/cache/inmemory/readFromStore.ts
@@ -477,7 +477,7 @@ export class StoreReader {
         }), i);
       }
 
-      if (process.env.NODE_ENV !== 'production') {
+      if (__DEV__) {
         assertSelectionSetForIdValue(context.store, field, item);
       }
 
diff --git a/src/cache/inmemory/writeToStore.ts b/src/cache/inmemory/writeToStore.ts
index d50f54ecdec..4317aae944e 100644
--- a/src/cache/inmemory/writeToStore.ts
+++ b/src/cache/inmemory/writeToStore.ts
@@ -269,7 +269,7 @@ export class StoreWriter {
         incomingFields = this.applyMerges(mergeTree, entityRef, incomingFields, context);
       }
 
-      if (process.env.NODE_ENV !== "production" && !context.overwrite) {
+      if (__DEV__ && !context.overwrite) {
         const hasSelectionSet = (storeFieldName: string) =>
           fieldsWithSelectionSets.has(fieldNameFromStoreName(storeFieldName));
         const fieldsWithSelectionSets = new Set<string>();
@@ -319,7 +319,7 @@ export class StoreWriter {
       // In development, we need to clone scalar values so that they can be
       // safely frozen with maybeDeepFreeze in readFromStore.ts. In production,
       // it's cheaper to store the scalar values directly in the cache.
-      return process.env.NODE_ENV === 'production' ? value : cloneDeep(value);
+      return __DEV__ ? cloneDeep(value) : value;
     }
 
     if (Array.isArray(value)) {
diff --git a/src/core/ApolloClient.ts b/src/core/ApolloClient.ts
index 9c63094c9bd..17e068ed8b2 100644
--- a/src/core/ApolloClient.ts
+++ b/src/core/ApolloClient.ts
@@ -151,7 +151,7 @@ export class ApolloClient<TCacheShape> implements DataProxy {
         // devtools, but disable them by default in production.
         typeof window === 'object' &&
         !(window as any).__APOLLO_CLIENT__ &&
-        process.env.NODE_ENV !== 'production',
+        __DEV__,
       queryDeduplication = true,
       defaultOptions,
       assumeImmutableResults = false,
@@ -205,7 +205,7 @@ export class ApolloClient<TCacheShape> implements DataProxy {
     /**
      * Suggest installing the devtools for developers who don't have them
      */
-    if (!hasSuggestedDevtools && process.env.NODE_ENV !== 'production') {
+    if (!hasSuggestedDevtools && __DEV__) {
       hasSuggestedDevtools = true;
       if (
         typeof window !== 'undefined' &&
diff --git a/src/core/ObservableQuery.ts b/src/core/ObservableQuery.ts
index 998cbb9577a..cbc9b964106 100644
--- a/src/core/ObservableQuery.ts
+++ b/src/core/ObservableQuery.ts
@@ -306,7 +306,7 @@ export class ObservableQuery<
       const { updateQuery } = fetchMoreOptions;
 
       if (updateQuery) {
-        if (process.env.NODE_ENV !== "production" &&
+        if (__DEV__ &&
             !warnedAboutUpdateQuery) {
           invariant.warn(
 `The updateQuery callback for fetchMore is deprecated, and will be removed
diff --git a/src/core/QueryManager.ts b/src/core/QueryManager.ts
index 8e56d630f5d..ddb8170754d 100644
--- a/src/core/QueryManager.ts
+++ b/src/core/QueryManager.ts
@@ -802,7 +802,7 @@ export class QueryManager<TStore> {
       });
     }
 
-    if (process.env.NODE_ENV !== "production" && queryNamesAndDocs.size) {
+    if (__DEV__ && queryNamesAndDocs.size) {
       queryNamesAndDocs.forEach((included, nameOrDoc) => {
         if (!included) {
           invariant.warn(`Unknown query ${
@@ -1364,7 +1364,7 @@ export class QueryManager<TStore> {
     ) => {
       const data = diff.result;
 
-      if (process.env.NODE_ENV !== 'production' &&
+      if (__DEV__ &&
           isNonEmptyArray(diff.missing) &&
           !equal(data, {}) &&
           !returnPartialData) {
diff --git a/src/core/index.ts b/src/core/index.ts
index c5c14217944..8e01d030b4c 100644
--- a/src/core/index.ts
+++ b/src/core/index.ts
@@ -1,5 +1,7 @@
 /* Core */
 
+export { __DEV__ } from "../utilities";
+
 export {
   ApolloClient,
   ApolloClientOptions,
diff --git a/src/react/index.ts b/src/react/index.ts
index a423c3c75a1..3d9c5583b9e 100644
--- a/src/react/index.ts
+++ b/src/react/index.ts
@@ -1,3 +1,5 @@
+export { __DEV__ } from "../utilities";
+
 export {
   ApolloProvider,
   ApolloConsumer,
diff --git a/src/utilities/common/__tests__/environment.ts b/src/utilities/common/__tests__/environment.ts
deleted file mode 100644
index f9fe25362db..00000000000
--- a/src/utilities/common/__tests__/environment.ts
+++ /dev/null
@@ -1,58 +0,0 @@
-import { isEnv, isDevelopment, isTest } from '../environment';
-
-describe('environment', () => {
-  let keepEnv: string | undefined;
-
-  beforeEach(() => {
-    // save the NODE_ENV
-    keepEnv = process.env.NODE_ENV;
-  });
-
-  afterEach(() => {
-    // restore the NODE_ENV
-    process.env.NODE_ENV = keepEnv;
-  });
-
-  describe('isEnv', () => {
-    it(`should match when there's a value`, () => {
-      ['production', 'development', 'test'].forEach(env => {
-        process.env.NODE_ENV = env;
-        expect(isEnv(env)).toBe(true);
-      });
-    });
-
-    it(`should treat no proces.env.NODE_ENV as it'd be in development`, () => {
-      delete process.env.NODE_ENV;
-      expect(isEnv('development')).toBe(true);
-    });
-  });
-
-  describe('isTest', () => {
-    it('should return true if in test', () => {
-      process.env.NODE_ENV = 'test';
-      expect(isTest()).toBe(true);
-    });
-
-    it('should return true if not in test', () => {
-      process.env.NODE_ENV = 'development';
-      expect(!isTest()).toBe(true);
-    });
-  });
-
-  describe('isDevelopment', () => {
-    it('should return true if in development', () => {
-      process.env.NODE_ENV = 'development';
-      expect(isDevelopment()).toBe(true);
-    });
-
-    it('should return true if not in development and environment is defined', () => {
-      process.env.NODE_ENV = 'test';
-      expect(!isDevelopment()).toBe(true);
-    });
-
-    it('should make development as the default environment', () => {
-      delete process.env.NODE_ENV;
-      expect(isDevelopment()).toBe(true);
-    });
-  });
-});
diff --git a/src/utilities/common/environment.ts b/src/utilities/common/environment.ts
deleted file mode 100644
index 21d61f5f122..00000000000
--- a/src/utilities/common/environment.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-export function getEnv(): string | undefined {
-  if (typeof process !== 'undefined' && process.env.NODE_ENV) {
-    return process.env.NODE_ENV;
-  }
-
-  // default environment
-  return 'development';
-}
-
-export function isEnv(env: string): boolean {
-  return getEnv() === env;
-}
-
-export function isDevelopment(): boolean {
-  return isEnv('development') === true;
-}
-
-export function isTest(): boolean {
-  return isEnv('test') === true;
-}
diff --git a/src/utilities/common/global.ts b/src/utilities/common/global.ts
new file mode 100644
index 00000000000..6464e27a3ca
--- /dev/null
+++ b/src/utilities/common/global.ts
@@ -0,0 +1,15 @@
+import { maybe } from "./maybe";
+
+declare global {
+  const __DEV__: boolean | undefined;
+}
+
+export default (
+  maybe(() => globalThis) ||
+  maybe(() => window) ||
+  maybe(() => self) ||
+  maybe(() => global) ||
+  maybe(() => Function("return this")())
+) as typeof globalThis & {
+  __DEV__: typeof __DEV__;
+};
diff --git a/src/utilities/common/maybe.ts b/src/utilities/common/maybe.ts
new file mode 100644
index 00000000000..dd9d4c90d80
--- /dev/null
+++ b/src/utilities/common/maybe.ts
@@ -0,0 +1,3 @@
+export function maybe<T>(thunk: () => T): T | undefined {
+  try { return thunk() } catch {}
+}
diff --git a/src/utilities/common/maybeDeepFreeze.ts b/src/utilities/common/maybeDeepFreeze.ts
index f8e9d483d1b..7cac2539b87 100644
--- a/src/utilities/common/maybeDeepFreeze.ts
+++ b/src/utilities/common/maybeDeepFreeze.ts
@@ -1,4 +1,4 @@
-import { isDevelopment, isTest } from './environment';
+import '../fixes'; // For __DEV__
 import { isNonNullObject } from './objects';
 
 function deepFreeze(value: any) {
@@ -15,7 +15,7 @@ function deepFreeze(value: any) {
 }
 
 export function maybeDeepFreeze<T>(obj: T): T {
-  if (process.env.NODE_ENV !== "production" && (isDevelopment() || isTest())) {
+  if (__DEV__) {
     deepFreeze(obj);
   }
   return obj;
diff --git a/src/utilities/fixes/__DEV__.ts b/src/utilities/fixes/__DEV__.ts
new file mode 100644
index 00000000000..2ff0f7aedfc
--- /dev/null
+++ b/src/utilities/fixes/__DEV__.ts
@@ -0,0 +1,21 @@
+import global from "../common/global";
+import { maybe } from "../common/maybe";
+
+function getDEV() {
+  try {
+    return Boolean(__DEV__);
+  } catch {
+    Object.defineProperty(global, "__DEV__", {
+      // In a buildless browser environment, maybe(() => process.env.NODE_ENV)
+      // evaluates as undefined, so __DEV__ becomes true by default, but can be
+      // initialized to false instead by a script/module that runs earlier.
+      value: maybe(() => process.env.NODE_ENV) !== "production",
+      enumerable: false,
+      configurable: true,
+      writable: true,
+    });
+    return global.__DEV__;
+  }
+}
+
+export default getDEV();
diff --git a/src/utilities/fixes/graphql.ts b/src/utilities/fixes/graphql.ts
new file mode 100644
index 00000000000..14acd0d021d
--- /dev/null
+++ b/src/utilities/fixes/graphql.ts
@@ -0,0 +1,14 @@
+// The ordering of these imports is important, because it ensures the temporary
+// process.env.NODE_ENV polyfill is defined globally (if necessary) before we
+// import { isType } from 'graphql'. The instanceOf function that we really care
+// about (the one that uses process.env.NODE_ENV) is not exported from the
+// top-level graphql package, but isType uses instanceOf, and is exported.
+import { undo } from './process';
+import { isType } from 'graphql';
+
+export function applyFixes() {
+  // Calling isType here just to make sure it won't be tree-shaken away,
+  // provided applyFixes is called elsewhere.
+  isType(null);
+  return undo();
+}
diff --git a/src/utilities/fixes/index.ts b/src/utilities/fixes/index.ts
new file mode 100644
index 00000000000..426dfd68a9f
--- /dev/null
+++ b/src/utilities/fixes/index.ts
@@ -0,0 +1,12 @@
+// Just in case the graphql package switches from process.env.NODE_ENV to
+// __DEV__, make sure __DEV__ is polyfilled before importing graphql.
+import { default as __DEV__ } from "./__DEV__";
+export { __DEV__ }
+
+// Import graphql/jsutils/instanceOf safely, working around its unchecked usage
+// of process.env.NODE_ENV and https://github.com/graphql/graphql-js/pull/2894.
+import { applyFixes } from "./graphql";
+
+// Synchronously undo the global process.env.NODE_ENV polyfill that we created
+// temporarily while importing the offending graphql/jsutils/instanceOf module.
+applyFixes();
diff --git a/src/utilities/fixes/process.ts b/src/utilities/fixes/process.ts
new file mode 100644
index 00000000000..40a31373693
--- /dev/null
+++ b/src/utilities/fixes/process.ts
@@ -0,0 +1,41 @@
+import { maybe } from "../common/maybe";
+import global from "../common/global";
+
+let needToUndo = false;
+
+if (global && maybe(() => process.env.NODE_ENV) === void 0) {
+  // Inherit from process and process.env, just in case they are defined.
+  const stub = Object.create(maybe(() => process) || null);
+  stub.env = Object.create(stub.env || null, {
+    NODE_ENV: {
+      // This default needs to be "production" instead of "development", to
+      // avoid the problem https://github.com/graphql/graphql-js/pull/2894
+      // will eventually solve, once merged.
+      value: "production",
+    },
+  });
+
+  try {
+    Object.defineProperty(global, "process", {
+      value: stub,
+      // Let anyone else change global.process as they see fit, but hide it from
+      // Object.keys(global) enumeration.
+      configurable: true,
+      enumerable: false,
+      writable: true,
+    });
+  } catch {
+    // If the global object is immutable, then we're out of luck, but we
+    // shouldn't crash the application just because of that.
+  }
+
+  // We expect this to be true now.
+  needToUndo = "process" in global;
+}
+
+export function undo() {
+  if (needToUndo) {
+    delete (global as any).process;
+    needToUndo = false;
+  }
+}
diff --git a/src/utilities/index.ts b/src/utilities/index.ts
index b5d8b3a51db..87e28b1e9d3 100644
--- a/src/utilities/index.ts
+++ b/src/utilities/index.ts
@@ -1,3 +1,5 @@
+export { __DEV__ } from "./fixes";
+
 export {
   DirectiveInfo,
   InclusionDirectives,