diff --git a/.changeset/salty-bobcats-sort.md b/.changeset/salty-bobcats-sort.md
new file mode 100644
index 0000000000..1475ec8d2a
--- /dev/null
+++ b/.changeset/salty-bobcats-sort.md
@@ -0,0 +1,6 @@
+---
+"@workflow/core": patch
+"@workflow/next": patch
+---
+
+Add Next.js pages router entries handling
diff --git a/packages/core/e2e/e2e.test.ts b/packages/core/e2e/e2e.test.ts
index aee736050c..25a3fac7bb 100644
--- a/packages/core/e2e/e2e.test.ts
+++ b/packages/core/e2e/e2e.test.ts
@@ -48,9 +48,13 @@ function writeE2EMetadata() {
 
 async function triggerWorkflow(
   workflow: string | { workflowFile: string; workflowFn: string },
-  args: any[]
+  args: any[],
+  options?: { usePagesRouter?: boolean }
 ): Promise<{ runId: string }> {
-  const url = new URL('/api/trigger', deploymentUrl);
+  const endpoint = options?.usePagesRouter
+    ? '/api/trigger-pages'
+    : '/api/trigger';
+  const url = new URL(endpoint, deploymentUrl);
   const workflowFn =
     typeof workflow === 'string' ? workflow : workflow.workflowFn;
   const workflowFile =
@@ -1292,4 +1296,46 @@ describe('e2e', () => {
       expect(runData.output).toBe(300);
     }
   );
+
+  // ==================== PAGES ROUTER TESTS ====================
+  // Tests for Next.js Pages Router API endpoint (only runs for nextjs-turbopack and nextjs-webpack)
+  const isNextJsApp =
+    process.env.APP_NAME === 'nextjs-turbopack' ||
+    process.env.APP_NAME === 'nextjs-webpack';
+
+  describe.skipIf(!isNextJsApp)('pages router', () => {
+    test('addTenWorkflow via pages router', { timeout: 60_000 }, async () => {
+      const run = await triggerWorkflow(
+        {
+          workflowFile: 'workflows/99_e2e.ts',
+          workflowFn: 'addTenWorkflow',
+        },
+        [123],
+        { usePagesRouter: true }
+      );
+      const returnValue = await getWorkflowReturnValue(run.runId);
+      expect(returnValue).toBe(133);
+    });
+
+    test(
+      'promiseAllWorkflow via pages router',
+      { timeout: 60_000 },
+      async () => {
+        const run = await triggerWorkflow('promiseAllWorkflow', [], {
+          usePagesRouter: true,
+        });
+        const returnValue = await getWorkflowReturnValue(run.runId);
+        expect(returnValue).toBe('ABC');
+      }
+    );
+
+    test('sleepingWorkflow via pages router', { timeout: 60_000 }, async () => {
+      const run = await triggerWorkflow('sleepingWorkflow', [], {
+        usePagesRouter: true,
+      });
+      const returnValue = await getWorkflowReturnValue(run.runId);
+      expect(returnValue.startTime).toBeLessThan(returnValue.endTime);
+      expect(returnValue.endTime - returnValue.startTime).toBeGreaterThan(9999);
+    });
+  });
 });
diff --git a/packages/next/src/builder.ts b/packages/next/src/builder.ts
index 5ec2ffe5a0..ebe0156345 100644
--- a/packages/next/src/builder.ts
+++ b/packages/next/src/builder.ts
@@ -350,12 +350,18 @@ export async function getNextBuilder() {
 
     protected async getInputFiles(): Promise<string[]> {
       const inputFiles = await super.getInputFiles();
-      return inputFiles.filter((item) =>
-        // non-exact pattern match to try to narrow
-        // down to just app route entrypoints, this will
-        // not be valid when pages router support is added
-        item.match(/[/\\](route|page|layout)\./)
-      );
+      return inputFiles.filter((item) => {
+        // Match App Router entrypoints: route.ts, page.ts, layout.ts in app/ or src/app/ directories
+        // Matches: /app/page.ts, /app/dashboard/page.ts, /src/app/route.ts, etc.
+        if (item.match(/(^|.*[/\\])(app|src[/\\]app)([/\\](route|page|layout)\.|[/\\].*[/\\](route|page|layout)\.)/)) {
+          return true;
+        }
+        // Match Pages Router entrypoints: files in pages/ or src/pages/
+        if (item.match(/[/\\](pages|src[/\\]pages)[/\\]/)) {
+          return true;
+        }
+        return false;
+      });
     }
 
     private async writeFunctionsConfig(outputDir: string) {
@@ -448,28 +454,52 @@ export async function getNextBuilder() {
     private async findAppDirectory(): Promise<string> {
       const appDir = resolve(this.config.workingDir, 'app');
       const srcAppDir = resolve(this.config.workingDir, 'src/app');
+      const pagesDir = resolve(this.config.workingDir, 'pages');
+      const srcPagesDir = resolve(this.config.workingDir, 'src/pages');
 
-      try {
-        await access(appDir, constants.F_OK);
-        const appStats = await stat(appDir);
-        if (!appStats.isDirectory()) {
-          throw new Error(`Path exists but is not a directory: ${appDir}`);
-        }
-        return appDir;
-      } catch {
+      // Helper to check if a path exists and is a directory
+      const isDirectory = async (path: string): Promise<boolean> => {
         try {
-          await access(srcAppDir, constants.F_OK);
-          const srcAppStats = await stat(srcAppDir);
-          if (!srcAppStats.isDirectory()) {
-            throw new Error(`Path exists but is not a directory: ${srcAppDir}`);
+          await access(path, constants.F_OK);
+          const stats = await stat(path);
+          if (!stats.isDirectory()) {
+            throw new Error(`Path exists but is not a directory: ${path}`);
           }
-          return srcAppDir;
-        } catch {
-          throw new Error(
-            'Could not find Next.js app directory. Expected either "app" or "src/app" to exist.'
-          );
+          return true;
+        } catch (e) {
+          if (e instanceof Error && e.message.includes('not a directory')) {
+            throw e;
+          }
+          return false;
         }
+      };
+
+      // Check if app directory exists
+      if (await isDirectory(appDir)) {
+        return appDir;
+      }
+
+      // Check if src/app directory exists
+      if (await isDirectory(srcAppDir)) {
+        return srcAppDir;
+      }
+
+      // If no app directory exists, check for pages directory and create app next to it
+      if (await isDirectory(pagesDir)) {
+        // Create app directory next to pages directory
+        await mkdir(appDir, { recursive: true });
+        return appDir;
+      }
+
+      if (await isDirectory(srcPagesDir)) {
+        // Create src/app directory next to src/pages directory
+        await mkdir(srcAppDir, { recursive: true });
+        return srcAppDir;
       }
+
+      throw new Error(
+        'Could not find Next.js app or pages directory. Expected one of: "app", "src/app", "pages", or "src/pages" to exist.'
+      );
     }
   }
 
diff --git a/workbench/nextjs-turbopack/pages/api/trigger-pages.ts b/workbench/nextjs-turbopack/pages/api/trigger-pages.ts
new file mode 100644
index 0000000000..34502caff3
--- /dev/null
+++ b/workbench/nextjs-turbopack/pages/api/trigger-pages.ts
@@ -0,0 +1,181 @@
+import type { NextApiRequest, NextApiResponse } from 'next';
+import { getRun, start } from 'workflow/api';
+import {
+  WorkflowRunFailedError,
+  WorkflowRunNotCompletedError,
+} from 'workflow/internal/errors';
+import { hydrateWorkflowArguments } from 'workflow/internal/serialization';
+import { allWorkflows } from '@/_workflows';
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  if (req.method === 'POST') {
+    return handlePost(req, res);
+  } else if (req.method === 'GET') {
+    return handleGet(req, res);
+  } else {
+    res.setHeader('Allow', ['GET', 'POST']);
+    return res.status(405).end(`Method ${req.method} Not Allowed`);
+  }
+}
+
+async function handlePost(req: NextApiRequest, res: NextApiResponse) {
+  const workflowFile =
+    (req.query.workflowFile as string) || 'workflows/99_e2e.ts';
+  if (!workflowFile) {
+    return res.status(400).send('No workflowFile query parameter provided');
+  }
+  const workflows = allWorkflows[workflowFile as keyof typeof allWorkflows];
+  if (!workflows) {
+    return res.status(400).send(`Workflow file "${workflowFile}" not found`);
+  }
+
+  const workflowFn = (req.query.workflowFn as string) || 'simple';
+  if (!workflowFn) {
+    return res.status(400).send('No workflow query parameter provided');
+  }
+
+  // Handle static method lookups (e.g., "Calculator.calculate")
+  let workflow: unknown;
+  if (workflowFn.includes('.')) {
+    const [className, methodName] = workflowFn.split('.');
+    const cls = workflows[className as keyof typeof workflows];
+    if (cls && typeof cls === 'function') {
+      workflow = (cls as Record<string, unknown>)[methodName];
+    }
+  } else {
+    workflow = workflows[workflowFn as keyof typeof workflows];
+  }
+  if (!workflow) {
+    return res.status(400).send(`Workflow "${workflowFn}" not found`);
+  }
+
+  let args: any[] = [];
+
+  // Args from query string
+  const argsParam = req.query.args as string | undefined;
+  if (argsParam) {
+    args = argsParam.split(',').map((arg) => {
+      const num = parseFloat(arg);
+      return Number.isNaN(num) ? arg.trim() : num;
+    });
+  } else {
+    // Args from body
+    args = hydrateWorkflowArguments(JSON.parse(req.body), globalThis);
+  }
+  console.log(`Starting "${workflowFn}" workflow with args: ${args}`);
+
+  try {
+    const run = await start(workflow as any, args as any);
+    console.log('Run', run.runId);
+    return res.status(200).json(run);
+  } catch (err) {
+    console.error(`Failed to start!!`, err);
+    throw err;
+  }
+}
+
+async function handleGet(req: NextApiRequest, res: NextApiResponse) {
+  const runId = req.query.runId as string | undefined;
+  if (!runId) {
+    return res.status(400).send('No runId provided');
+  }
+
+  const outputStreamParam = req.query['output-stream'] as string | undefined;
+  if (outputStreamParam) {
+    const namespace = outputStreamParam === '1' ? undefined : outputStreamParam;
+    const run = getRun(runId);
+    const stream = run.getReadable({
+      namespace,
+    });
+
+    res.setHeader('Content-Type', 'application/octet-stream');
+
+    const reader = stream.getReader();
+    try {
+      while (true) {
+        const { done, value } = await reader.read();
+        if (done) break;
+        const data =
+          value instanceof Uint8Array
+            ? { data: Buffer.from(value).toString('base64') }
+            : value;
+        res.write(`${JSON.stringify(data)}\n`);
+      }
+    } finally {
+      reader.releaseLock();
+    }
+    return res.end();
+  }
+
+  try {
+    const run = getRun(runId);
+    const returnValue = await run.returnValue;
+    console.log('Return value:', returnValue);
+
+    // Include run metadata in headers
+    const [createdAt, startedAt, completedAt] = await Promise.all([
+      run.createdAt,
+      run.startedAt,
+      run.completedAt,
+    ]);
+
+    res.setHeader('X-Workflow-Run-Created-At', createdAt?.toISOString() || '');
+    res.setHeader('X-Workflow-Run-Started-At', startedAt?.toISOString() || '');
+    res.setHeader(
+      'X-Workflow-Run-Completed-At',
+      completedAt?.toISOString() || ''
+    );
+
+    if (returnValue instanceof ReadableStream) {
+      res.setHeader('Content-Type', 'application/octet-stream');
+      const reader = returnValue.getReader();
+      try {
+        while (true) {
+          const { done, value } = await reader.read();
+          if (done) break;
+          res.write(value);
+        }
+      } finally {
+        reader.releaseLock();
+      }
+      return res.end();
+    }
+
+    return res.status(200).json(returnValue);
+  } catch (error) {
+    if (error instanceof Error) {
+      if (WorkflowRunNotCompletedError.is(error)) {
+        return res.status(202).json({
+          ...error,
+          name: error.name,
+          message: error.message,
+        });
+      }
+
+      if (WorkflowRunFailedError.is(error)) {
+        const cause = error.cause;
+        return res.status(400).json({
+          ...error,
+          name: error.name,
+          message: error.message,
+          cause: {
+            message: cause.message,
+            stack: cause.stack,
+            code: cause.code,
+          },
+        });
+      }
+    }
+
+    console.error(
+      'Unexpected error while getting workflow return value:',
+      error
+    );
+    return res.status(500).json({
+      error: 'Internal server error',
+    });
+  }
+}
diff --git a/workbench/nextjs-webpack/pages/api/trigger-pages.ts b/workbench/nextjs-webpack/pages/api/trigger-pages.ts
new file mode 100644
index 0000000000..34502caff3
--- /dev/null
+++ b/workbench/nextjs-webpack/pages/api/trigger-pages.ts
@@ -0,0 +1,181 @@
+import type { NextApiRequest, NextApiResponse } from 'next';
+import { getRun, start } from 'workflow/api';
+import {
+  WorkflowRunFailedError,
+  WorkflowRunNotCompletedError,
+} from 'workflow/internal/errors';
+import { hydrateWorkflowArguments } from 'workflow/internal/serialization';
+import { allWorkflows } from '@/_workflows';
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  if (req.method === 'POST') {
+    return handlePost(req, res);
+  } else if (req.method === 'GET') {
+    return handleGet(req, res);
+  } else {
+    res.setHeader('Allow', ['GET', 'POST']);
+    return res.status(405).end(`Method ${req.method} Not Allowed`);
+  }
+}
+
+async function handlePost(req: NextApiRequest, res: NextApiResponse) {
+  const workflowFile =
+    (req.query.workflowFile as string) || 'workflows/99_e2e.ts';
+  if (!workflowFile) {
+    return res.status(400).send('No workflowFile query parameter provided');
+  }
+  const workflows = allWorkflows[workflowFile as keyof typeof allWorkflows];
+  if (!workflows) {
+    return res.status(400).send(`Workflow file "${workflowFile}" not found`);
+  }
+
+  const workflowFn = (req.query.workflowFn as string) || 'simple';
+  if (!workflowFn) {
+    return res.status(400).send('No workflow query parameter provided');
+  }
+
+  // Handle static method lookups (e.g., "Calculator.calculate")
+  let workflow: unknown;
+  if (workflowFn.includes('.')) {
+    const [className, methodName] = workflowFn.split('.');
+    const cls = workflows[className as keyof typeof workflows];
+    if (cls && typeof cls === 'function') {
+      workflow = (cls as Record<string, unknown>)[methodName];
+    }
+  } else {
+    workflow = workflows[workflowFn as keyof typeof workflows];
+  }
+  if (!workflow) {
+    return res.status(400).send(`Workflow "${workflowFn}" not found`);
+  }
+
+  let args: any[] = [];
+
+  // Args from query string
+  const argsParam = req.query.args as string | undefined;
+  if (argsParam) {
+    args = argsParam.split(',').map((arg) => {
+      const num = parseFloat(arg);
+      return Number.isNaN(num) ? arg.trim() : num;
+    });
+  } else {
+    // Args from body
+    args = hydrateWorkflowArguments(JSON.parse(req.body), globalThis);
+  }
+  console.log(`Starting "${workflowFn}" workflow with args: ${args}`);
+
+  try {
+    const run = await start(workflow as any, args as any);
+    console.log('Run', run.runId);
+    return res.status(200).json(run);
+  } catch (err) {
+    console.error(`Failed to start!!`, err);
+    throw err;
+  }
+}
+
+async function handleGet(req: NextApiRequest, res: NextApiResponse) {
+  const runId = req.query.runId as string | undefined;
+  if (!runId) {
+    return res.status(400).send('No runId provided');
+  }
+
+  const outputStreamParam = req.query['output-stream'] as string | undefined;
+  if (outputStreamParam) {
+    const namespace = outputStreamParam === '1' ? undefined : outputStreamParam;
+    const run = getRun(runId);
+    const stream = run.getReadable({
+      namespace,
+    });
+
+    res.setHeader('Content-Type', 'application/octet-stream');
+
+    const reader = stream.getReader();
+    try {
+      while (true) {
+        const { done, value } = await reader.read();
+        if (done) break;
+        const data =
+          value instanceof Uint8Array
+            ? { data: Buffer.from(value).toString('base64') }
+            : value;
+        res.write(`${JSON.stringify(data)}\n`);
+      }
+    } finally {
+      reader.releaseLock();
+    }
+    return res.end();
+  }
+
+  try {
+    const run = getRun(runId);
+    const returnValue = await run.returnValue;
+    console.log('Return value:', returnValue);
+
+    // Include run metadata in headers
+    const [createdAt, startedAt, completedAt] = await Promise.all([
+      run.createdAt,
+      run.startedAt,
+      run.completedAt,
+    ]);
+
+    res.setHeader('X-Workflow-Run-Created-At', createdAt?.toISOString() || '');
+    res.setHeader('X-Workflow-Run-Started-At', startedAt?.toISOString() || '');
+    res.setHeader(
+      'X-Workflow-Run-Completed-At',
+      completedAt?.toISOString() || ''
+    );
+
+    if (returnValue instanceof ReadableStream) {
+      res.setHeader('Content-Type', 'application/octet-stream');
+      const reader = returnValue.getReader();
+      try {
+        while (true) {
+          const { done, value } = await reader.read();
+          if (done) break;
+          res.write(value);
+        }
+      } finally {
+        reader.releaseLock();
+      }
+      return res.end();
+    }
+
+    return res.status(200).json(returnValue);
+  } catch (error) {
+    if (error instanceof Error) {
+      if (WorkflowRunNotCompletedError.is(error)) {
+        return res.status(202).json({
+          ...error,
+          name: error.name,
+          message: error.message,
+        });
+      }
+
+      if (WorkflowRunFailedError.is(error)) {
+        const cause = error.cause;
+        return res.status(400).json({
+          ...error,
+          name: error.name,
+          message: error.message,
+          cause: {
+            message: cause.message,
+            stack: cause.stack,
+            code: cause.code,
+          },
+        });
+      }
+    }
+
+    console.error(
+      'Unexpected error while getting workflow return value:',
+      error
+    );
+    return res.status(500).json({
+      error: 'Internal server error',
+    });
+  }
+}