diff --git a/packages/react-relay/relay-hooks/useMutation.js b/packages/react-relay/relay-hooks/useMutation.js
index d7dfa82820748..0f97bacf39f26 100644
--- a/packages/react-relay/relay-hooks/useMutation.js
+++ b/packages/react-relay/relay-hooks/useMutation.js
@@ -12,11 +12,11 @@
 'use strict';
 
 import type {
+  CommitMutationConfig,
   DeclarativeMutationConfig,
   Disposable,
   IEnvironment,
   Mutation,
-  MutationConfig,
   MutationParameters,
   PayloadError,
   SelectorStoreUpdater,
@@ -68,17 +68,7 @@ function useMutation<TVariables: Variables, TData, TRawResponse = {...}>(
   mutation: Mutation<TVariables, TData, TRawResponse>,
   commitMutationFn?: (
     environment: IEnvironment,
-    config: MutationConfig<{
-      variables: TVariables,
-      /* $FlowFixMe[incompatible-type-arg] error exposed when improving flow
-       * typing of useMutation */
-      response: TData,
-      /* $FlowFixMe[incompatible-type-arg] error exposed when improving flow
-       * typing of useMutation */
-      rawResponse?: TRawResponse,
-    }>,
-    /* $FlowFixMe[incompatible-type-arg] error exposed when improving flow typing
-     * of useMutation */
+    config: CommitMutationConfig<TVariables, TData, TRawResponse>,
   ) => Disposable = defaultCommitMutation,
 ): [
   (UseMutationConfigInternal<TVariables, TData, TRawResponse>) => Disposable,
diff --git a/packages/relay-runtime/index.js b/packages/relay-runtime/index.js
index 4638742a4eb29..048525474165b 100644
--- a/packages/relay-runtime/index.js
+++ b/packages/relay-runtime/index.js
@@ -83,7 +83,10 @@ export type {
   RangeOperation,
 } from './mutations/RelayDeclarativeMutationConfig';
 export type {OptimisticMutationConfig} from './mutations/applyOptimisticMutation';
-export type {MutationConfig} from './mutations/commitMutation';
+export type {
+  MutationConfig,
+  CommitMutationConfig,
+} from './mutations/commitMutation';
 export type {
   ExecuteFunction,
   FetchFunction,
diff --git a/packages/relay-runtime/mutations/__tests__/commitMutation-test.js b/packages/relay-runtime/mutations/__tests__/commitMutation-test.js
index baac50bf24153..3d60c2be3f2ae 100644
--- a/packages/relay-runtime/mutations/__tests__/commitMutation-test.js
+++ b/packages/relay-runtime/mutations/__tests__/commitMutation-test.js
@@ -144,6 +144,8 @@ describe('Configs: NODE_DELETE', () => {
     store.subscribe(snapshot, callback);
     commitMutation(environment, {
       configs,
+      /* $FlowFixMe[prop-missing] error exposed when improving flow typing of
+       * commitMutation */
       mutation,
       optimisticResponse,
       optimisticUpdater,
@@ -595,6 +597,10 @@ describe('Configs: RANGE_ADD', () => {
     store.subscribe(snapshot, callback);
     commitMutation(environment, {
       configs,
+      /* $FlowFixMe[prop-missing] error exposed when improving flow typing of
+       * commitMutation */
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
       mutation,
       optimisticResponse,
       optimisticUpdater,
@@ -651,6 +657,10 @@ describe('Configs: RANGE_ADD', () => {
     // send mutation
     commitMutation(environment, {
       configs,
+      /* $FlowFixMe[prop-missing] error exposed when improving flow typing of
+       * commitMutation */
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
       mutation,
       variables,
     });
@@ -736,6 +746,10 @@ describe('Configs: RANGE_ADD', () => {
     // send the same mutation again
     commitMutation(environment, {
       configs,
+      /* $FlowFixMe[prop-missing] error exposed when improving flow typing of
+       * commitMutation */
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
       mutation,
       variables,
     });
@@ -816,6 +830,10 @@ describe('Configs: RANGE_ADD', () => {
     store.subscribe(snapshot, callback);
     commitMutation(environment, {
       configs,
+      /* $FlowFixMe[prop-missing] error exposed when improving flow typing of
+       * commitMutation */
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
       mutation,
       optimisticResponse,
       optimisticUpdater,
@@ -881,6 +899,10 @@ describe('Configs: RANGE_ADD', () => {
     store.subscribe(snapshot, callback);
     commitMutation(environment, {
       configs,
+      /* $FlowFixMe[prop-missing] error exposed when improving flow typing of
+       * commitMutation */
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
       mutation,
       optimisticResponse,
       optimisticUpdater,
@@ -936,6 +958,10 @@ describe('Configs: RANGE_ADD', () => {
     // send mutation
     commitMutation(environment, {
       updater,
+      /* $FlowFixMe[prop-missing] error exposed when improving flow typing of
+       * commitMutation */
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
       mutation,
       variables,
     });
@@ -1027,6 +1053,10 @@ describe('Configs: RANGE_ADD', () => {
     // send the same mutation again
     commitMutation(environment, {
       updater,
+      /* $FlowFixMe[prop-missing] error exposed when improving flow typing of
+       * commitMutation */
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
       mutation,
       variables,
     });
diff --git a/packages/relay-runtime/mutations/commitMutation.js b/packages/relay-runtime/mutations/commitMutation.js
index c4eed0b6b8558..00754e506b829 100644
--- a/packages/relay-runtime/mutations/commitMutation.js
+++ b/packages/relay-runtime/mutations/commitMutation.js
@@ -18,7 +18,12 @@ import type {
   MutationParameters,
   SelectorStoreUpdater,
 } from '../store/RelayStoreTypes';
-import type {CacheConfig, Disposable} from '../util/RelayRuntimeTypes';
+import type {
+  CacheConfig,
+  Disposable,
+  Mutation,
+  Variables,
+} from '../util/RelayRuntimeTypes';
 import type {DeclarativeMutationConfig} from './RelayDeclarativeMutationConfig';
 
 const {getRequest} = require('../query/GraphQLTag');
@@ -54,13 +59,28 @@ export type MutationConfig<TMutation: MutationParameters> = {
   variables: TMutation['variables'],
 };
 
+export type CommitMutationConfig<TVariables, TData, TRawResponse> = {
+  cacheConfig?: CacheConfig,
+  configs?: Array<DeclarativeMutationConfig>,
+  mutation: Mutation<TVariables, TData, TRawResponse>,
+  onCompleted?: ?(response: TData, errors: ?Array<PayloadError>) => void,
+  onError?: ?(error: Error) => void,
+  onNext?: ?() => void,
+  onUnsubscribe?: ?() => void,
+  optimisticResponse?: TRawResponse,
+  optimisticUpdater?: ?SelectorStoreUpdater<TData>,
+  updater?: ?SelectorStoreUpdater<TData>,
+  uploadables?: UploadableMap,
+  variables: TVariables,
+};
+
 /**
  * Higher-level helper function to execute a mutation against a specific
  * environment.
  */
-function commitMutation<TMutation: MutationParameters>(
+function commitMutation<TVariables: Variables, TData, TRawResponse = {...}>(
   environment: IEnvironment,
-  config: MutationConfig<TMutation>,
+  config: CommitMutationConfig<TVariables, TData, TRawResponse>,
 ): Disposable {
   invariant(
     isRelayModernEnvironment(environment),
@@ -85,6 +105,8 @@ function commitMutation<TMutation: MutationParameters>(
   );
   // TODO: remove this check after we fix flow.
   if (typeof optimisticResponse === 'function') {
+    /* $FlowFixMe[incompatible-use] error exposed when improving flow typing of
+     * commitMutation */
     optimisticResponse = optimisticResponse();
     warning(
       false,
@@ -98,16 +120,21 @@ function commitMutation<TMutation: MutationParameters>(
     }
   }
   if (configs) {
-    ({optimisticUpdater, updater} = RelayDeclarativeMutationConfig.convert(
-      configs,
-      mutation,
-      optimisticUpdater,
-      updater,
-    ));
+    ({optimisticUpdater, updater} = RelayDeclarativeMutationConfig.convert<{
+      variables: TVariables,
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
+      response: TData,
+    }>(configs, mutation, optimisticUpdater, updater));
   }
   const errors: Array<PayloadError> = [];
   const subscription = environment
-    .executeMutation({
+    .executeMutation<{
+      variables: TVariables,
+      /* $FlowFixMe[incompatible-call] error exposed when improving flow typing
+       * of commitMutation */
+      response: TData,
+    }>({
       operation,
       optimisticResponse,
       optimisticUpdater,