diff --git a/docs/src/api/params.md b/docs/src/api/params.md
index c59cb1e920f5e..000f6d929bc2c 100644
--- a/docs/src/api/params.md
+++ b/docs/src/api/params.md
@@ -1287,7 +1287,7 @@ relative path, then it is resolved relative to the current working directory. If
 saved to the disk.
 
 ## screenshot-option-type
-- `type` <[ScreenshotType]<"png"|"jpeg">>
+- `type` <[ScreenshotType]<"png"|"jpeg"|"webp">>
 
 Specify screenshot type, defaults to `png`.
 
diff --git a/packages/playwright-client/types/types.d.ts b/packages/playwright-client/types/types.d.ts
index d9902ca08932a..5e7cfe832c6d2 100644
--- a/packages/playwright-client/types/types.d.ts
+++ b/packages/playwright-client/types/types.d.ts
@@ -12313,7 +12313,7 @@ export interface ElementHandle<T=Node> extends JSHandle<T> {
     /**
      * Specify screenshot type, defaults to `png`.
      */
-    type?: "png"|"jpeg";
+    type?: "png"|"jpeg"|"webp";
   }): Promise<Buffer>;
 
   /**
@@ -24124,7 +24124,7 @@ export interface LocatorScreenshotOptions {
   /**
    * Specify screenshot type, defaults to `png`.
    */
-  type?: "png"|"jpeg";
+  type?: "png"|"jpeg"|"webp";
 }
 
 interface ElementHandleWaitForSelectorOptions {
@@ -24797,7 +24797,7 @@ export interface PageScreenshotOptions {
   /**
    * Specify screenshot type, defaults to `png`.
    */
-  type?: "png"|"jpeg";
+  type?: "png"|"jpeg"|"webp";
 }
 
 type Devices = {
diff --git a/packages/playwright-core/src/client/elementHandle.ts b/packages/playwright-core/src/client/elementHandle.ts
index 99e3c555d9411..1d81046381626 100644
--- a/packages/playwright-core/src/client/elementHandle.ts
+++ b/packages/playwright-core/src/client/elementHandle.ts
@@ -317,13 +317,15 @@ export async function convertInputFiles(platform: Platform, files: string | File
   return { payloads };
 }
 
-export function determineScreenshotType(options: { path?: string, type?: 'png' | 'jpeg' }): 'png' | 'jpeg' | undefined {
+export function determineScreenshotType(options: { path?: string, type?: 'png' | 'jpeg' | 'webp' }): 'png' | 'jpeg' | 'webp' | undefined {
   if (options.path) {
     const mimeType = getMimeTypeForPath(options.path);
     if (mimeType === 'image/png')
       return 'png';
     else if (mimeType === 'image/jpeg')
       return 'jpeg';
+    else if (mimeType === 'image/webp')
+      return 'webp';
     throw new Error(`path: unsupported mime type "${mimeType}"`);
   }
   return options.type;
diff --git a/packages/playwright-core/src/protocol/validator.ts b/packages/playwright-core/src/protocol/validator.ts
index 656817e780068..78b9bf147d019 100644
--- a/packages/playwright-core/src/protocol/validator.ts
+++ b/packages/playwright-core/src/protocol/validator.ts
@@ -1872,7 +1872,7 @@ scheme.ElementHandleQuerySelectorAllResult = tObject({
 });
 scheme.ElementHandleScreenshotParams = tObject({
   timeout: tFloat,
-  type: tOptional(tEnum(['png', 'jpeg'])),
+  type: tOptional(tEnum(['png', 'jpeg', 'webp'])),
   quality: tOptional(tInt),
   omitBackground: tOptional(tBoolean),
   caret: tOptional(tEnum(['hide', 'initial'])),
@@ -2430,7 +2430,7 @@ scheme.PageExpectScreenshotResult = tObject({
 });
 scheme.PageScreenshotParams = tObject({
   timeout: tFloat,
-  type: tOptional(tEnum(['png', 'jpeg'])),
+  type: tOptional(tEnum(['png', 'jpeg', 'webp'])),
   quality: tOptional(tInt),
   fullPage: tOptional(tBoolean),
   clip: tOptional(tType('Rect')),
diff --git a/packages/playwright-core/src/server/bidi/bidiPage.ts b/packages/playwright-core/src/server/bidi/bidiPage.ts
index 6637b0d46ee96..49e34a88628a6 100644
--- a/packages/playwright-core/src/server/bidi/bidiPage.ts
+++ b/packages/playwright-core/src/server/bidi/bidiPage.ts
@@ -479,6 +479,8 @@ export class BidiPage implements PageDelegate {
   }
 
   async takeScreenshot(progress: Progress, format: string, documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
+    if (format === 'webp')
+      throw new Error('webp screenshots are not supported via WebDriver BiDi');
     const rect = (documentRect || viewportRect)!;
     const { data } = await progress.race(this._session.send('browsingContext.captureScreenshot', {
       context: this._session.sessionId,
diff --git a/packages/playwright-core/src/server/chromium/crPage.ts b/packages/playwright-core/src/server/chromium/crPage.ts
index 19556b0536e8e..5fd57f88fce63 100644
--- a/packages/playwright-core/src/server/chromium/crPage.ts
+++ b/packages/playwright-core/src/server/chromium/crPage.ts
@@ -247,7 +247,7 @@ export class CRPage implements PageDelegate {
     await this._mainFrameSession._client.send('Emulation.setDefaultBackgroundColorOverride', { color });
   }
 
-  async takeScreenshot(progress: Progress, format: 'png' | 'jpeg', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
+  async takeScreenshot(progress: Progress, format: 'png' | 'jpeg' | 'webp', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
     const { visualViewport, contentSize, cssContentSize } = await progress.race(this._mainFrameSession._client.send('Page.getLayoutMetrics'));
     if (!documentRect) {
       documentRect = {
diff --git a/packages/playwright-core/src/server/firefox/ffPage.ts b/packages/playwright-core/src/server/firefox/ffPage.ts
index c269a97763069..301c81c3a4e79 100644
--- a/packages/playwright-core/src/server/firefox/ffPage.ts
+++ b/packages/playwright-core/src/server/firefox/ffPage.ts
@@ -455,7 +455,7 @@ export class FFPage implements PageDelegate {
       throw new Error('Not implemented');
   }
 
-  async takeScreenshot(progress: Progress, format: 'png' | 'jpeg', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
+  async takeScreenshot(progress: Progress, format: 'png' | 'jpeg' | 'webp', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
     if (!documentRect) {
       const scrollOffset = await this._page.mainFrame().waitForFunctionValueInUtility(progress, () => ({ x: window.scrollX, y: window.scrollY }));
       documentRect = {
@@ -466,7 +466,7 @@ export class FFPage implements PageDelegate {
       };
     }
     const { data } = await progress.race(this._session.send('Page.screenshot', {
-      mimeType: ('image/' + format) as ('image/png' | 'image/jpeg'),
+      mimeType: ('image/' + format) as ('image/png' | 'image/jpeg' | 'image/webp'),
       clip: documentRect,
       quality,
       omitDeviceScaleFactor: scale === 'css',
diff --git a/packages/playwright-core/src/server/screenshotter.ts b/packages/playwright-core/src/server/screenshotter.ts
index c29e9e0b7c5e7..bccd5dde0ca44 100644
--- a/packages/playwright-core/src/server/screenshotter.ts
+++ b/packages/playwright-core/src/server/screenshotter.ts
@@ -35,7 +35,7 @@ declare global {
 }
 
 export type ScreenshotOptions = {
-  type?: 'png' | 'jpeg';
+  type?: 'png' | 'jpeg' | 'webp';
   quality?: number;
   omitBackground?: boolean;
   animations?: 'disabled' | 'allow';
@@ -297,7 +297,7 @@ export class Screenshotter {
     }
   }
 
-  private async _screenshot(progress: Progress, format: 'png' | 'jpeg', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, fitsViewport: boolean, options: ScreenshotOptions): Promise<Buffer> {
+  private async _screenshot(progress: Progress, format: 'png' | 'jpeg' | 'webp', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, fitsViewport: boolean, options: ScreenshotOptions): Promise<Buffer> {
     if ((options as any).__testHookBeforeScreenshot)
       await progress.race((options as any).__testHookBeforeScreenshot());
 
@@ -307,7 +307,7 @@ export class Screenshotter {
     const cleanupHighlight = await this._maskElements(progress, options);
 
     try {
-      const quality = format === 'jpeg' ? options.quality ?? 80 : undefined;
+      const quality = format === 'jpeg' ? options.quality ?? 80 : format === 'webp' ? options.quality : undefined;
       const buffer = await this._page.delegate.takeScreenshot(progress, format, documentRect, viewportRect, quality, fitsViewport, options.scale || 'device');
       await progress.race(cleanupHighlight());
       if (shouldSetDefaultBackground)
@@ -353,12 +353,12 @@ function trimClipToSize(clip: types.Rect, size: types.Size): types.Rect {
   return result;
 }
 
-export function validateScreenshotOptions(options: ScreenshotOptions): 'png' | 'jpeg' {
-  let format: 'png' | 'jpeg' | null = null;
+export function validateScreenshotOptions(options: ScreenshotOptions): 'png' | 'jpeg' | 'webp' {
+  let format: 'png' | 'jpeg' | 'webp' | null = null;
   // options.type takes precedence over inferring the type from options.path
   // because it may be a 0-length file with no extension created beforehand (i.e. as a temp file).
   if (options.type) {
-    assert(options.type === 'png' || options.type === 'jpeg', 'Unknown options.type value: ' + options.type);
+    assert(options.type === 'png' || options.type === 'jpeg' || options.type === 'webp', 'Unknown options.type value: ' + options.type);
     format = options.type;
   }
 
@@ -366,7 +366,7 @@ export function validateScreenshotOptions(options: ScreenshotOptions): 'png' | '
     format = 'png';
 
   if (options.quality !== undefined) {
-    assert(format === 'jpeg', 'options.quality is unsupported for the ' + format + ' screenshots');
+    assert(format !== 'png', 'options.quality is unsupported for the ' + format + ' screenshots');
     assert(typeof options.quality === 'number', 'Expected options.quality to be a number but found ' + (typeof options.quality));
     assert(Number.isInteger(options.quality), 'Expected options.quality to be an integer');
     assert(options.quality >= 0 && options.quality <= 100, 'Expected options.quality to be between 0 and 100 (inclusive), got ' + options.quality);
diff --git a/packages/playwright-core/src/server/webkit/wkPage.ts b/packages/playwright-core/src/server/webkit/wkPage.ts
index 6a2540390e809..0f027d24939ad 100644
--- a/packages/playwright-core/src/server/webkit/wkPage.ts
+++ b/packages/playwright-core/src/server/webkit/wkPage.ts
@@ -15,8 +15,6 @@
  * limitations under the License.
  */
 
-import { PNG } from 'pngjs';
-import jpegjs from 'jpeg-js';
 import { headersArrayToObject, headersObjectToArray } from '@isomorphic/headers';
 import { splitErrorMessage } from '@isomorphic/stackTrace';
 import { eventsHelper } from '@utils/eventsHelper';
@@ -870,16 +868,15 @@ export class WKPage implements PageDelegate {
   }
 
   async takeScreenshot(progress: Progress, format: string, documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
+    if (format === 'webp' && process.platform === 'darwin')
+      throw new Error('webp screenshots are not supported in WebKit on macOS');
     const rect = (documentRect || viewportRect)!;
     const omitDeviceScaleFactor = scale === 'css';
     this.validateScreenshotDimension(rect.width, omitDeviceScaleFactor);
     this.validateScreenshotDimension(rect.height, omitDeviceScaleFactor);
-    const result = await progress.race(this._session.send('Page.snapshotRect', { ...rect, coordinateSystem: documentRect ? 'Page' : 'Viewport', omitDeviceScaleFactor }));
-    const prefix = 'data:image/png;base64,';
-    let buffer: Buffer = Buffer.from(result.dataURL.substr(prefix.length), 'base64');
-    if (format === 'jpeg')
-      buffer = jpegjs.encode(PNG.sync.read(buffer), quality).data;
-    return buffer;
+    const result = await progress.race(this._session.send('Page.snapshotRect', { ...rect, coordinateSystem: documentRect ? 'Page' : 'Viewport', omitDeviceScaleFactor, format: format as 'png' | 'jpeg' | 'webp', quality }));
+    // Strip 'data:image/png;base64,' prefix.
+    return Buffer.from(result.dataURL.substring(result.dataURL.indexOf(',') + 1), 'base64');
   }
 
   async getContentFrame(handle: dom.ElementHandle): Promise<frames.Frame | null> {
diff --git a/packages/playwright-core/src/tools/backend/response.ts b/packages/playwright-core/src/tools/backend/response.ts
index db10fb696f5cd..a562e1dc984e8 100644
--- a/packages/playwright-core/src/tools/backend/response.ts
+++ b/packages/playwright-core/src/tools/backend/response.ts
@@ -58,7 +58,7 @@ export class Response {
   readonly toolName: string;
   readonly toolArgs: Record<string, any>;
   private _clientWorkspace: string;
-  private _imageResults: { data: Buffer, imageType: 'png' | 'jpeg' }[] = [];
+  private _imageResults: { data: Buffer, imageType: 'png' | 'jpeg' | 'webp' }[] = [];
   private _raw: boolean;
   private _json: boolean;
   private _writtenFiles = new Set<string>();
@@ -127,7 +127,7 @@ export class Response {
     this.addTextResult(`- [${title}](${relativeName})`);
   }
 
-  async registerImageResult(data: Buffer, imageType: 'png' | 'jpeg') {
+  async registerImageResult(data: Buffer, imageType: 'png' | 'jpeg' | 'webp') {
     this._imageResults.push({ data, imageType });
   }
 
@@ -219,7 +219,7 @@ export class Response {
     if (this._context.config.imageResponses !== 'omit') {
       for (const imageResult of this._imageResults) {
         const scaledData = scaleImageToFitMessage(imageResult.data, imageResult.imageType);
-        content.push({ type: 'image', data: scaledData.toString('base64'), mimeType: imageResult.imageType === 'png' ? 'image/png' : 'image/jpeg' });
+        content.push({ type: 'image', data: scaledData.toString('base64'), mimeType: `image/${imageResult.imageType}` });
       }
     }
 
diff --git a/packages/playwright-core/src/tools/backend/screenshot.ts b/packages/playwright-core/src/tools/backend/screenshot.ts
index d2aeea504a2d3..69f61eaca229d 100644
--- a/packages/playwright-core/src/tools/backend/screenshot.ts
+++ b/packages/playwright-core/src/tools/backend/screenshot.ts
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+import path from 'path';
+
 import jpegjs from 'jpeg-js';
 import { PNG } from 'pngjs';
 import * as z from 'zod';
@@ -25,12 +27,26 @@ import { optionalElementSchema } from './snapshot';
 
 import type * as playwright from '../../..';
 
+type ImageFormat = 'png' | 'jpeg' | 'webp';
+
 const screenshotSchema = optionalElementSchema.extend({
-  type: z.enum(['png', 'jpeg']).default('png').describe('Image format for the screenshot. Default is png.'),
-  filename: z.string().optional().describe('File name to save the screenshot to. Defaults to `page-{timestamp}.{png|jpeg}` if not specified. Prefer relative file names to stay within the output directory.'),
+  type: z.enum(['png', 'jpeg', 'webp']).optional().describe('Image format for the screenshot. If unset, inferred from the filename extension, otherwise png.'),
+  filename: z.string().optional().describe('File name to save the screenshot to. Defaults to `page-{timestamp}.{png|jpeg|webp}` if not specified. Prefer relative file names to stay within the output directory.'),
   fullPage: z.boolean().optional().describe('When true, takes a screenshot of the full scrollable page, instead of the currently visible viewport. Cannot be used with element screenshots.'),
 });
 
+function inferTypeFromFilename(filename: string | undefined): ImageFormat | undefined {
+  if (!filename)
+    return undefined;
+  switch (path.extname(filename).toLowerCase()) {
+    case '.png': return 'png';
+    case '.jpg':
+    case '.jpeg': return 'jpeg';
+    case '.webp': return 'webp';
+  }
+  return undefined;
+}
+
 const screenshot = defineTabTool({
   capability: 'core',
   schema: {
@@ -45,10 +61,10 @@ const screenshot = defineTabTool({
     if (params.fullPage && params.target)
       throw new Error('fullPage cannot be used with element screenshots.');
 
-    const fileType = params.type || 'png';
+    const fileType: ImageFormat = params.type ?? inferTypeFromFilename(params.filename) ?? 'png';
     const options: playwright.PageScreenshotOptions = {
       type: fileType,
-      quality: fileType === 'png' ? undefined : 90,
+      quality: fileType === 'jpeg' ? 90 : undefined,
       scale: 'css',
       ...tab.actionTimeoutOptions,
       ...(params.fullPage !== undefined && { fullPage: params.fullPage })
@@ -72,10 +88,14 @@ const screenshot = defineTabTool({
   }
 });
 
-export function scaleImageToFitMessage(buffer: Buffer, imageType: 'png' | 'jpeg'): Buffer {
+export function scaleImageToFitMessage(buffer: Buffer, imageType: 'png' | 'jpeg' | 'webp'): Buffer {
   // https://docs.claude.com/en/docs/build-with-claude/vision#evaluate-image-size
   // Not more than 1.15 megapixel, linear size not more than 1568.
 
+  // No Node-side webp decoder is bundled, so we can't scale webp screenshots.
+  if (imageType === 'webp')
+    return buffer;
+
   const image = imageType === 'png' ? PNG.sync.read(buffer) : jpegjs.decode(buffer, { maxMemoryUsageInMB: 512 });
   const pixels = image.width * image.height;
 
diff --git a/packages/playwright-core/src/tools/cli-daemon/commands.ts b/packages/playwright-core/src/tools/cli-daemon/commands.ts
index 689f7b0e358a9..2fc6cce6ebc7a 100644
--- a/packages/playwright-core/src/tools/cli-daemon/commands.ts
+++ b/packages/playwright-core/src/tools/cli-daemon/commands.ts
@@ -789,11 +789,12 @@ const screenshot = declareCommand({
     target: z.string().optional().describe(elementTargetDescription),
   }),
   options: z.object({
-    filename: z.string().optional().describe('File name to save the screenshot to. Defaults to `page-{timestamp}.{png|jpeg}` if not specified.'),
+    filename: z.string().optional().describe('File name to save the screenshot to. Defaults to `page-{timestamp}.{png|jpeg|webp}` if not specified.'),
+    type: z.enum(['png', 'jpeg', 'webp']).optional().describe('Image format. If unset, inferred from the filename extension, otherwise png.'),
     ['full-page']: z.boolean().optional().describe('When true, takes a screenshot of the full scrollable page, instead of the currently visible viewport.'),
   }),
   toolName: 'browser_take_screenshot',
-  toolParams: ({ target, filename, ['full-page']: fullPage }) => ({ filename, target, fullPage }),
+  toolParams: ({ target, filename, type, ['full-page']: fullPage }) => ({ filename, target, type, fullPage }),
 });
 
 const pdfSave = declareCommand({
diff --git a/packages/playwright-core/src/tools/cli-daemon/helpGenerator.ts b/packages/playwright-core/src/tools/cli-daemon/helpGenerator.ts
index 0074b5d5cdf7d..7590700a16382 100644
--- a/packages/playwright-core/src/tools/cli-daemon/helpGenerator.ts
+++ b/packages/playwright-core/src/tools/cli-daemon/helpGenerator.ts
@@ -56,7 +56,10 @@ function generateCommandHelp(command: AnyCommandSchema) {
     const optionsShape = (command.options as zodType.ZodObject<any>).shape;
     for (const [name, schema] of Object.entries(optionsShape)) {
       const zodSchema = schema as zodType.ZodTypeAny;
-      const description = (zodSchema.description ?? '').toLowerCase();
+      let description = (zodSchema.description ?? '').toLowerCase();
+      const unwrapped = unwrapZodType(zodSchema);
+      if (unwrapped instanceof z.ZodEnum)
+        description = `${description} (one of: ${unwrapped.options.join(', ')})`.trim();
       lines.push(formatWithGap(`  --${name}`, description));
     }
   }
diff --git a/packages/playwright-core/types/types.d.ts b/packages/playwright-core/types/types.d.ts
index d9902ca08932a..5e7cfe832c6d2 100644
--- a/packages/playwright-core/types/types.d.ts
+++ b/packages/playwright-core/types/types.d.ts
@@ -12313,7 +12313,7 @@ export interface ElementHandle<T=Node> extends JSHandle<T> {
     /**
      * Specify screenshot type, defaults to `png`.
      */
-    type?: "png"|"jpeg";
+    type?: "png"|"jpeg"|"webp";
   }): Promise<Buffer>;
 
   /**
@@ -24124,7 +24124,7 @@ export interface LocatorScreenshotOptions {
   /**
    * Specify screenshot type, defaults to `png`.
    */
-  type?: "png"|"jpeg";
+  type?: "png"|"jpeg"|"webp";
 }
 
 interface ElementHandleWaitForSelectorOptions {
@@ -24797,7 +24797,7 @@ export interface PageScreenshotOptions {
   /**
    * Specify screenshot type, defaults to `png`.
    */
-  type?: "png"|"jpeg";
+  type?: "png"|"jpeg"|"webp";
 }
 
 type Devices = {
diff --git a/packages/protocol/spec/handles.yml b/packages/protocol/spec/handles.yml
index 1a4a77fb4c693..61fbee34e878c 100644
--- a/packages/protocol/spec/handles.yml
+++ b/packages/protocol/spec/handles.yml
@@ -405,6 +405,7 @@ ElementHandle:
           literals:
           - png
           - jpeg
+          - webp
         quality: int?
         $mixin: CommonScreenshotOptions
       returns:
diff --git a/packages/protocol/spec/page.yml b/packages/protocol/spec/page.yml
index c1b077c04bf07..4091f0cfa39b5 100644
--- a/packages/protocol/spec/page.yml
+++ b/packages/protocol/spec/page.yml
@@ -210,6 +210,7 @@ Page:
           literals:
           - png
           - jpeg
+          - webp
         quality: int?
         fullPage: boolean?
         clip: Rect?
diff --git a/packages/protocol/src/channels.d.ts b/packages/protocol/src/channels.d.ts
index 02409015ca5a4..12d2b8bcfbc0e 100644
--- a/packages/protocol/src/channels.d.ts
+++ b/packages/protocol/src/channels.d.ts
@@ -3377,7 +3377,7 @@ export type ElementHandleQuerySelectorAllResult = {
 };
 export type ElementHandleScreenshotParams = {
   timeout: number,
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
@@ -3391,7 +3391,7 @@ export type ElementHandleScreenshotParams = {
   style?: string,
 };
 export type ElementHandleScreenshotOptions = {
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
@@ -4334,7 +4334,7 @@ export type PageExpectScreenshotResult = {
 };
 export type PageScreenshotParams = {
   timeout: number,
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   fullPage?: boolean,
   clip?: Rect,
@@ -4350,7 +4350,7 @@ export type PageScreenshotParams = {
   style?: string,
 };
 export type PageScreenshotOptions = {
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   fullPage?: boolean,
   clip?: Rect,
diff --git a/tests/mcp/cli-save-as.spec.ts b/tests/mcp/cli-save-as.spec.ts
index b566c0c022d9c..c1b57c6d7cb80 100644
--- a/tests/mcp/cli-save-as.spec.ts
+++ b/tests/mcp/cli-save-as.spec.ts
@@ -46,6 +46,17 @@ test('screenshot --filename', async ({ cli, server, mcpBrowser }) => {
   expect(attachments[0].data).toEqual(expect.any(Buffer));
 });
 
+test('screenshot --filename infers webp from extension', async ({ cli, server, mcpBrowser }) => {
+  test.skip(mcpBrowser === 'webkit' && process.platform === 'darwin', 'CG on macOS does not include a webp encoder UTI');
+
+  await cli('open', server.HELLO_WORLD);
+  const { output, attachments } = await cli('screenshot', '--filename=screenshot.webp');
+  expect(output).toContain('[Screenshot of viewport](./screenshot.webp)');
+  const buffer = attachments[0].data as Buffer;
+  expect(buffer.subarray(0, 4).toString('latin1')).toBe('RIFF');
+  expect(buffer.subarray(8, 12).toString('latin1')).toBe('WEBP');
+});
+
 test('pdf', async ({ cli, server, mcpBrowser }) => {
   test.skip(mcpBrowser !== 'chromium' && mcpBrowser !== 'chrome', 'PDF is only supported in Chromium and Chrome');
   await cli('open', server.HELLO_WORLD);
diff --git a/tests/mcp/screenshot.spec.ts b/tests/mcp/screenshot.spec.ts
index faa0d7d5eec73..294a54b8e343f 100644
--- a/tests/mcp/screenshot.spec.ts
+++ b/tests/mcp/screenshot.spec.ts
@@ -96,8 +96,10 @@ test('--output-dir should work', async ({ startClient, server }, testInfo) => {
   expect(files[0]).toMatch(/^page-\d{4}-\d{2}-\d{2}T\d{2}-\d{2}-\d{2}-\d{3}Z\.png$/);
 });
 
-for (const type of ['png', 'jpeg']) {
-  test(`browser_take_screenshot (type: ${type})`, async ({ startClient, server }, testInfo) => {
+for (const type of ['png', 'jpeg', 'webp']) {
+  test(`browser_take_screenshot (type: ${type})`, async ({ startClient, server, mcpBrowser }, testInfo) => {
+    test.skip(type === 'webp' && mcpBrowser === 'webkit' && process.platform === 'darwin', 'CG on macOS does not include a webp encoder UTI');
+
     const outputDir = testInfo.outputPath('output');
     const { client } = await startClient({
       config: { outputDir },
diff --git a/tests/page/page-screenshot.spec.ts b/tests/page/page-screenshot.spec.ts
index a2f7b77b3c8a5..aa647f66353d7 100644
--- a/tests/page/page-screenshot.spec.ts
+++ b/tests/page/page-screenshot.spec.ts
@@ -266,6 +266,36 @@ it.describe('page screenshot', () => {
     expect(screenshot).toMatchSnapshot('white.jpg');
   });
 
+  it('should produce a valid webp screenshot', async ({ page, server, isBidi, browserName, platform }) => {
+    it.skip(isBidi, 'webp screenshots are not supported via WebDriver BiDi');
+    it.skip(browserName === 'webkit' && platform === 'darwin', 'CG on macOS does not include a webp encoder UTI');
+
+    await page.setViewportSize({ width: 300, height: 300 });
+    await page.goto(server.EMPTY_PAGE);
+    await page.evaluate(() => (document.body.style.background = 'rgb(255, 0, 0)'));
+    const screenshot = await page.screenshot({ type: 'webp' });
+    // Valid WebP container: "RIFF" <size> "WEBP".
+    expect(screenshot.subarray(0, 4).toString('latin1')).toBe('RIFF');
+    expect(screenshot.subarray(8, 12).toString('latin1')).toBe('WEBP');
+    // Decode it back in the page to confirm it carries the rendered content.
+    const pixel = await page.evaluate(async base64 => {
+      const img = new Image();
+      img.src = 'data:image/webp;base64,' + base64;
+      await img.decode();
+      const canvas = document.createElement('canvas');
+      canvas.width = img.naturalWidth;
+      canvas.height = img.naturalHeight;
+      const context = canvas.getContext('2d')!;
+      context.drawImage(img, 0, 0);
+      const data = context.getImageData(canvas.width >> 1, canvas.height >> 1, 1, 1).data;
+      return { width: img.naturalWidth, r: data[0], g: data[1], b: data[2] };
+    }, screenshot.toString('base64'));
+    expect(pixel.width).toBeGreaterThan(0);
+    expect(pixel.r).toBeGreaterThan(200);
+    expect(pixel.g).toBeLessThan(60);
+    expect(pixel.b).toBeLessThan(60);
+  });
+
   it('should work with odd clip size on Retina displays', async ({ page, isElectron }) => {
     it.fixme(isElectron, 'Scale is wrong');