diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
index 9f139dd3baf15..3a7d7205dcb27 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
@@ -320,4 +320,84 @@ describe('ReactDOMFizzServer', () => {
       </div>,
     );
   });
+
+  // @gate experimental
+  it('should allow for two containers to be written to the same document', async () => {
+    // We create two passthrough streams for each container to write into.
+    // Notably we don't implement a end() call for these. Because we don't want to
+    // close the underlying stream just because one of the streams is done. Instead
+    // we manually close when both are done.
+    const writableA = new Stream.Writable();
+    writableA._write = (chunk, encoding, next) => {
+      writable.write(chunk, encoding, next);
+    };
+    const writableB = new Stream.Writable();
+    writableB._write = (chunk, encoding, next) => {
+      writable.write(chunk, encoding, next);
+    };
+
+    writable.write('<div id="container-A">');
+    await act(async () => {
+      const {startWriting} = ReactDOMFizzServer.pipeToNodeWritable(
+        <Suspense fallback={<Text text="Loading A..." />}>
+          <Text text="This will show A: " />
+          <div>
+            <AsyncText text="A" />
+          </div>
+        </Suspense>,
+        writableA,
+        {identifierPrefix: 'A_'},
+      );
+      startWriting();
+    });
+    writable.write('</div>');
+
+    writable.write('<div id="container-B">');
+    await act(async () => {
+      const {startWriting} = ReactDOMFizzServer.pipeToNodeWritable(
+        <Suspense fallback={<Text text="Loading B..." />}>
+          <Text text="This will show B: " />
+          <div>
+            <AsyncText text="B" />
+          </div>
+        </Suspense>,
+        writableB,
+        {identifierPrefix: 'B_'},
+      );
+      startWriting();
+    });
+    writable.write('</div>');
+
+    expect(getVisibleChildren(container)).toEqual([
+      <div id="container-A">Loading A...</div>,
+      <div id="container-B">Loading B...</div>,
+    ]);
+
+    await act(async () => {
+      resolveText('B');
+    });
+
+    expect(getVisibleChildren(container)).toEqual([
+      <div id="container-A">Loading A...</div>,
+      <div id="container-B">
+        This will show B: <div>B</div>
+      </div>,
+    ]);
+
+    await act(async () => {
+      resolveText('A');
+    });
+
+    // We're done writing both streams now.
+    writable.end();
+
+    expect(getVisibleChildren(container)).toEqual([
+      <div id="container-A">
+        This will show A: <div>A</div>
+      </div>,
+      <div id="container-B">
+        This will show B: <div>B</div>
+      </div>,
+    ]);
+  });
 });
diff --git a/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js b/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js
index b310271291e2e..902989fefca0f 100644
--- a/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js
+++ b/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js
@@ -16,9 +16,12 @@ import {
   abort,
 } from 'react-server/src/ReactFizzServer';
 
+import {createResponseState} from './ReactDOMServerFormatConfig';
+
 type Options = {
-  signal?: AbortSignal,
+  identifierPrefix?: string,
   progressiveChunkSize?: number,
+  signal?: AbortSignal,
 };
 
 function renderToReadableStream(
@@ -39,6 +42,7 @@ function renderToReadableStream(
       request = createRequest(
         children,
         controller,
+        createResponseState(options ? options.identifierPrefix : undefined),
         options ? options.progressiveChunkSize : undefined,
       );
       startWork(request);
diff --git a/packages/react-dom/src/server/ReactDOMFizzServerNode.js b/packages/react-dom/src/server/ReactDOMFizzServerNode.js
index 1bc2506927dbb..8de76f7095f9d 100644
--- a/packages/react-dom/src/server/ReactDOMFizzServerNode.js
+++ b/packages/react-dom/src/server/ReactDOMFizzServerNode.js
@@ -17,11 +17,14 @@ import {
   abort,
 } from 'react-server/src/ReactFizzServer';
 
+import {createResponseState} from './ReactDOMServerFormatConfig';
+
 function createDrainHandler(destination, request) {
   return () => startFlowing(request);
 }
 
 type Options = {
+  identifierPrefix?: string,
   progressiveChunkSize?: number,
 };
 
@@ -39,6 +42,7 @@ function pipeToNodeWritable(
   const request = createRequest(
     children,
     destination,
+    createResponseState(options ? options.identifierPrefix : undefined),
     options ? options.progressiveChunkSize : undefined,
   );
   let hasStartedFlowing = false;
diff --git a/packages/react-dom/src/server/ReactDOMServerFormatConfig.js b/packages/react-dom/src/server/ReactDOMServerFormatConfig.js
index 250892b31d4a0..e9d337724e194 100644
--- a/packages/react-dom/src/server/ReactDOMServerFormatConfig.js
+++ b/packages/react-dom/src/server/ReactDOMServerFormatConfig.js
@@ -24,6 +24,10 @@ import invariant from 'shared/invariant';
 
 // Per response,
 export type ResponseState = {
+  placeholderPrefix: PrecomputedChunk,
+  segmentPrefix: PrecomputedChunk,
+  boundaryPrefix: string,
+  opaqueIdentifierPrefix: PrecomputedChunk,
   nextSuspenseID: number,
   sentCompleteSegmentFunction: boolean,
   sentCompleteBoundaryFunction: boolean,
@@ -31,8 +35,14 @@ export type ResponseState = {
 };
 
 // Allows us to keep track of what we've already written so we can refer back to it.
-export function createResponseState(): ResponseState {
+export function createResponseState(
+  identifierPrefix: string = '',
+): ResponseState {
   return {
+    placeholderPrefix: stringToPrecomputedChunk(identifierPrefix + 'P:'),
+    segmentPrefix: stringToPrecomputedChunk(identifierPrefix + 'S:'),
+    boundaryPrefix: identifierPrefix + 'B:',
+    opaqueIdentifierPrefix: stringToPrecomputedChunk(identifierPrefix + 'R:'),
     nextSuspenseID: 0,
     sentCompleteSegmentFunction: false,
     sentCompleteBoundaryFunction: false,
@@ -68,7 +78,7 @@ function assignAnID(
   // TODO: This approach doesn't yield deterministic results since this is assigned during render.
   const generatedID = responseState.nextSuspenseID++;
   return (id.formattedID = stringToPrecomputedChunk(
-    'B:' + generatedID.toString(16),
+    responseState.boundaryPrefix + generatedID.toString(16),
   ));
 }
 
@@ -160,20 +170,19 @@ export function pushEndInstance(
 // A placeholder is a node inside a hidden partial tree that can be filled in later, but before
 // display. It's never visible to users.
 const placeholder1 = stringToPrecomputedChunk('<span id="');
-const placeholder2 = stringToPrecomputedChunk('P:');
-const placeholder3 = stringToPrecomputedChunk('"></span>');
+const placeholder2 = stringToPrecomputedChunk('"></span>');
 export function writePlaceholder(
   destination: Destination,
+  responseState: ResponseState,
   id: number,
 ): boolean {
   // TODO: This needs to be contextually aware and switch tag since not all parents allow for spans like
   // <select> or <tbody>. E.g. suspending a component that renders a table row.
   writeChunk(destination, placeholder1);
-  // TODO: Use the identifierPrefix option to make the prefix configurable.
-  writeChunk(destination, placeholder2);
+  writeChunk(destination, responseState.placeholderPrefix);
   const formattedID = stringToChunk(id.toString(16));
   writeChunk(destination, formattedID);
-  return writeChunk(destination, placeholder3);
+  return writeChunk(destination, placeholder2);
 }
 
 // Suspense boundaries are encoded as comments.
@@ -207,20 +216,19 @@ export function writeEndSuspenseBoundary(destination: Destination): boolean {
 }
 
 const startSegment = stringToPrecomputedChunk('<div hidden id="');
-const startSegment2 = stringToPrecomputedChunk('S:');
-const startSegment3 = stringToPrecomputedChunk('">');
+const startSegment2 = stringToPrecomputedChunk('">');
 const endSegment = stringToPrecomputedChunk('</div>');
 export function writeStartSegment(
   destination: Destination,
+  responseState: ResponseState,
   id: number,
 ): boolean {
   // TODO: What happens with special children like <tr> if they're inserted in a div? Maybe needs contextually aware containers.
   writeChunk(destination, startSegment);
-  // TODO: Use the identifierPrefix option to make the prefix configurable.
-  writeChunk(destination, startSegment2);
+  writeChunk(destination, responseState.segmentPrefix);
   const formattedID = stringToChunk(id.toString(16));
   writeChunk(destination, formattedID);
-  return writeChunk(destination, startSegment3);
+  return writeChunk(destination, startSegment2);
 }
 export function writeEndSegment(destination: Destination): boolean {
   return writeChunk(destination, endSegment);
@@ -349,12 +357,10 @@ const clientRenderFunction =
   'function $RX(b){if(b=document.getElementById(b)){do b=b.previousSibling;while(8!==b.nodeType||"$?"!==b.data);b.data="$!";b._reactRetry&&b._reactRetry()}}';
 
 const completeSegmentScript1Full = stringToPrecomputedChunk(
-  '<script>' + completeSegmentFunction + ';$RS("S:',
-);
-const completeSegmentScript1Partial = stringToPrecomputedChunk(
-  '<script>$RS("S:',
+  '<script>' + completeSegmentFunction + ';$RS("',
 );
-const completeSegmentScript2 = stringToPrecomputedChunk('","P:');
+const completeSegmentScript1Partial = stringToPrecomputedChunk('<script>$RS("');
+const completeSegmentScript2 = stringToPrecomputedChunk('","');
 const completeSegmentScript3 = stringToPrecomputedChunk('")</script>');
 
 export function writeCompletedSegmentInstruction(
@@ -370,10 +376,11 @@ export function writeCompletedSegmentInstruction(
     // Future calls can just reuse the same function.
     writeChunk(destination, completeSegmentScript1Partial);
   }
-  // TODO: Use the identifierPrefix option to make the prefix configurable.
+  writeChunk(destination, responseState.segmentPrefix);
   const formattedID = stringToChunk(contentSegmentID.toString(16));
   writeChunk(destination, formattedID);
   writeChunk(destination, completeSegmentScript2);
+  writeChunk(destination, responseState.placeholderPrefix);
   writeChunk(destination, formattedID);
   return writeChunk(destination, completeSegmentScript3);
 }
@@ -384,7 +391,7 @@ const completeBoundaryScript1Full = stringToPrecomputedChunk(
 const completeBoundaryScript1Partial = stringToPrecomputedChunk(
   '<script>$RC("',
 );
-const completeBoundaryScript2 = stringToPrecomputedChunk('","S:');
+const completeBoundaryScript2 = stringToPrecomputedChunk('","');
 const completeBoundaryScript3 = stringToPrecomputedChunk('")</script>');
 
 export function writeCompletedBoundaryInstruction(
@@ -401,7 +408,6 @@ export function writeCompletedBoundaryInstruction(
     // Future calls can just reuse the same function.
     writeChunk(destination, completeBoundaryScript1Partial);
   }
-  // TODO: Use the identifierPrefix option to make the prefix configurable.
   const formattedBoundaryID = boundaryID.formattedID;
   invariant(
     formattedBoundaryID !== null,
@@ -410,6 +416,7 @@ export function writeCompletedBoundaryInstruction(
   const formattedContentID = stringToChunk(contentSegmentID.toString(16));
   writeChunk(destination, formattedBoundaryID);
   writeChunk(destination, completeBoundaryScript2);
+  writeChunk(destination, responseState.segmentPrefix);
   writeChunk(destination, formattedContentID);
   return writeChunk(destination, completeBoundaryScript3);
 }
diff --git a/packages/react-native-renderer/src/server/ReactNativeServerFormatConfig.js b/packages/react-native-renderer/src/server/ReactNativeServerFormatConfig.js
index e8f6b9e14afff..d89fafea818e3 100644
--- a/packages/react-native-renderer/src/server/ReactNativeServerFormatConfig.js
+++ b/packages/react-native-renderer/src/server/ReactNativeServerFormatConfig.js
@@ -145,6 +145,7 @@ function formatID(id: number): Uint8Array {
 // display. It's never visible to users.
 export function writePlaceholder(
   destination: Destination,
+  responseState: ResponseState,
   id: number,
 ): boolean {
   writeChunk(destination, PLACEHOLDER);
@@ -179,6 +180,7 @@ export function writeEndSuspenseBoundary(destination: Destination): boolean {
 
 export function writeStartSegment(
   destination: Destination,
+  responseState: ResponseState,
   id: number,
 ): boolean {
   writeChunk(destination, SEGMENT);
diff --git a/packages/react-noop-renderer/src/ReactNoopServer.js b/packages/react-noop-renderer/src/ReactNoopServer.js
index 99392ebed6db5..d2a4bf032933c 100644
--- a/packages/react-noop-renderer/src/ReactNoopServer.js
+++ b/packages/react-noop-renderer/src/ReactNoopServer.js
@@ -77,9 +77,6 @@ const ReactNoopServer = ReactFizzServer({
   closeWithError(destination: Destination, error: mixed): void {},
   flushBuffered(destination: Destination): void {},
 
-  createResponseState(): null {
-    return null;
-  },
   createSuspenseBoundaryID(): SuspenseInstance {
     // The ID is a pointer to the boundary itself.
     return {state: 'pending', children: []};
@@ -114,7 +111,11 @@ const ReactNoopServer = ReactFizzServer({
     target.push(POP);
   },
 
-  writePlaceholder(destination: Destination, id: number): boolean {
+  writePlaceholder(
+    destination: Destination,
+    responseState: ResponseState,
+    id: number,
+  ): boolean {
     const parent = destination.stack[destination.stack.length - 1];
     destination.placeholders.set(id, {
       parent: parent,
@@ -153,7 +154,11 @@ const ReactNoopServer = ReactFizzServer({
     destination.stack.pop();
   },
 
-  writeStartSegment(destination: Destination, id: number): boolean {
+  writeStartSegment(
+    destination: Destination,
+    responseState: ResponseState,
+    id: number,
+  ): boolean {
     const segment = {
       children: [],
     };
@@ -227,6 +232,7 @@ function render(children: React$Element<any>, options?: Options): Destination {
   const request = ReactNoopServer.createRequest(
     children,
     destination,
+    null,
     options ? options.progressiveChunkSize : undefined,
   );
   ReactNoopServer.startWork(request);
diff --git a/packages/react-server/src/ReactFizzServer.js b/packages/react-server/src/ReactFizzServer.js
index 54049da40b39f..265bfb89c24f4 100644
--- a/packages/react-server/src/ReactFizzServer.js
+++ b/packages/react-server/src/ReactFizzServer.js
@@ -44,7 +44,6 @@ import {
   pushStartInstance,
   pushEndInstance,
   createSuspenseBoundaryID,
-  createResponseState,
 } from './ReactServerFormatConfig';
 import {REACT_ELEMENT_TYPE, REACT_SUSPENSE_TYPE} from 'shared/ReactSymbols';
 import ReactSharedInternals from 'shared/ReactSharedInternals';
@@ -133,13 +132,14 @@ const DEFAULT_PROGRESSIVE_CHUNK_SIZE = 12800;
 export function createRequest(
   children: ReactNodeList,
   destination: Destination,
+  responseState: ResponseState,
   progressiveChunkSize: number = DEFAULT_PROGRESSIVE_CHUNK_SIZE,
 ): Request {
   const pingedWork = [];
   const abortSet: Set<SuspendedWork> = new Set();
   const request = {
     destination,
-    responseState: createResponseState(),
+    responseState,
     progressiveChunkSize,
     status: BUFFERING,
     nextSegmentId: 0,
@@ -590,7 +590,7 @@ function flushSubtree(
       // We're emitting a placeholder for this segment to be filled in later.
       // Therefore we'll need to assign it an ID - to refer to it by.
       const segmentID = (segment.id = request.nextSegmentId++);
-      return writePlaceholder(destination, segmentID);
+      return writePlaceholder(destination, request.responseState, segmentID);
     }
     case COMPLETED: {
       segment.status = FLUSHED;
@@ -712,7 +712,7 @@ function flushSegmentContainer(
   destination: Destination,
   segment: Segment,
 ): boolean {
-  writeStartSegment(destination, segment.id);
+  writeStartSegment(destination, request.responseState, segment.id);
   flushSegment(request, destination, segment);
   return writeEndSegment(destination);
 }
diff --git a/packages/react-server/src/forks/ReactServerFormatConfig.custom.js b/packages/react-server/src/forks/ReactServerFormatConfig.custom.js
index 3f3688ad4fb88..76219e1a0748e 100644
--- a/packages/react-server/src/forks/ReactServerFormatConfig.custom.js
+++ b/packages/react-server/src/forks/ReactServerFormatConfig.custom.js
@@ -28,7 +28,6 @@ export opaque type Destination = mixed; // eslint-disable-line no-undef
 export opaque type ResponseState = mixed;
 export opaque type SuspenseBoundaryID = mixed;
 
-export const createResponseState = $$$hostConfig.createResponseState;
 export const createSuspenseBoundaryID = $$$hostConfig.createSuspenseBoundaryID;
 export const pushEmpty = $$$hostConfig.pushEmpty;
 export const pushTextInstance = $$$hostConfig.pushTextInstance;