Requestly Alternative Chrome Extension (2026)

If you rely on Requestly for intercepting API requests, modifying headers, or mocking responses during development, you is looking for alternatives that better fit your workflow or budget. While Requestly offers a solid feature set, several Chrome extensions in 2026 provide comparable or specialized functionality for developers who need fine-grained control over HTTP traffic.

This guide covers the best Requestly alternatives for Chrome in 2026, with practical examples and use cases to help you choose the right tool for your development needs.

Understanding What Requestly Provides

Requestly is a Chrome extension that allows developers to modify network requests without touching the actual code. Common use cases include:

  • Redirecting API endpoints during development
  • Adding or modifying HTTP headers
  • Delaying network requests for testing
  • Mocking API responses
  • Blocking specific requests

For many developers, these capabilities are essential during frontend development, API testing, and debugging. However, depending on your specific needs, you might find better options elsewhere.

Requestly has moved increasingly toward a team and enterprise pricing model in recent years, which means solo developers and small teams now face friction with the free tier. The free plan limits the number of active rules and lacks features like rule sharing and session recording that were previously unrestricted. This pricing shift is a primary reason many developers are evaluating alternatives in 2026.

Quick Comparison: Requestly vs. Alternatives

Before diving into each tool, here is a high-level comparison of the most important capabilities:

Feature Requestly ModHeader Mockey Request Interceptor MSW
Header modification Yes Yes No Yes No
API mocking Yes No Yes Yes Yes
Redirect rules Yes No No Yes No
Response delay Yes No Yes Yes Yes
GraphQL support Partial No No No Yes
Team sharing Paid No No No Yes (via code)
Works in tests No No No No Yes
Free tier limits Yes No No No Open source

The tradeoffs are real. Extensions are quick to set up but only work in the browser during manual testing. Code-based solutions like MSW add setup overhead but provide consistent behavior across browsers, automated tests, and CI pipelines.

Top Requestly Alternatives in 2026

  1. ModHeader

ModHeader is a straightforward Chrome extension focused on modifying HTTP request and response headers. It is particularly useful for developers who need to quickly test different authentication scenarios or debug header-related issues.

Key Features:

  • Add, modify, or remove request/response headers
  • Create multiple profiles for different environments
  • Apply headers conditionally based on URL patterns
  • Export and import profiles as JSON

Practical Example:

// Using ModHeader to add a custom header for API testing
{
 "Request Headers": [
 { "name": "X-Debug-Mode", "value": "true" },
 { "name": "Authorization", "value": "Bearer test-token-123" }
 ]
}

ModHeader’s profile system is especially useful when you regularly switch between environments. A “staging” profile might include a staging API key and a debug header, while a “production debug” profile adds a trace header to production requests without changing auth credentials. Switching between them takes one click.

ModHeader also supports URL filters so headers only apply to specific domains. This prevents accidentally sending debug headers to third-party APIs that share a tab session:

// ModHeader conditional profile example
{
 "title": "Internal API Debug",
 "filters": [
 {
 "comment": "Only apply to internal API endpoints",
 "urlPattern": "https://api.yourcompany.com/*",
 "enabled": true
 }
 ],
 "headers": [
 { "name": "X-Internal-Debug", "value": "1" },
 { "name": "X-Request-Id", "value": "dev-session-001" }
 ]
}

Best For: Developers who primarily need header modification without complex routing rules.

  1. Mockey

Mockey is a dedicated API mocking tool that runs entirely in your browser. Unlike extensions that intercept live traffic, Mockey lets you define complete mock responses that your application can consume.

Key Features:

  • Define mock responses with custom status codes
  • Support for JSON, XML, and plain text responses
  • URL parameter matching
  • Response delay simulation

Practical Example:

// Sample mock configuration in Mockey
{
 "endpoint": "/api/users/*",
 "method": "GET",
 "response": {
 "status": 200,
 "body": {
 "users": [
 { "id": 1, "name": "Developer One" },
 { "id": 2, "name": "Developer Two" }
 ]
 }
 },
 "delay": 500
}

The delay simulation feature is genuinely useful for testing loading states that are difficult to reproduce against fast local or staging APIs. Setting a 2000ms delay on a critical data fetch reveals whether your skeleton screens and loading spinners behave correctly under realistic network conditions.

You can also configure error responses to test how your application handles API failures:

// Simulating a server error to test error handling
{
 "endpoint": "/api/payments/process",
 "method": "POST",
 "response": {
 "status": 503,
 "body": {
 "error": "Service temporarily unavailable",
 "retry_after": 30
 }
 },
 "delay": 1200
}

Best For: Frontend developers who need stable mock APIs without setting up a local server.

  1. Request Interceptor

Request Interceptor focuses on intercepting and modifying network requests in real-time. It provides a clean interface for creating rules that match specific URL patterns and apply transformations.

Key Features:

  • Real-time request interception
  • Pattern-based URL matching using wildcards
  • Request/response body modification
  • Export and import rule configurations

Practical Example:

// Rule configuration for redirecting API calls
{
 "rules": [
 {
 "pattern": "https://api.production.com/*",
 "action": "redirect",
 "target": "https://api.staging.com/*"
 },
 {
 "pattern": "https://api.*.com/users",
 "action": "modify_response",
 "modifications": {
 "delay": 1000
 }
 }
 ]
}

Request Interceptor’s export and import functionality makes it practical for teams to share rule sets. A team lead can define a set of redirect rules for a new microservice being developed in parallel and share the JSON configuration with the team so everyone points at the same stub server without any code changes:

// Shareable rule set for a feature in development
{
 "version": "1.0",
 "rules": [
 {
 "name": "Redirect to new recommendations service",
 "enabled": true,
 "pattern": "https://api.myapp.com/v1/recommendations*",
 "action": "redirect",
 "target": "https://recommendations-dev.internal.myapp.com/v2/recommendations*"
 },
 {
 "name": "Inject feature flag header",
 "enabled": true,
 "pattern": "https://api.myapp.com/*",
 "action": "add_request_header",
 "header": { "name": "X-Feature-NewRecs", "value": "true" }
 }
 ]
}

Best For: Developers who need to switch between different API environments quickly.

  1. JSONPlaceholder Client

For developers who need quick API testing without setting up endpoints, the JSONPlaceholder client provides a ready-made fake API that supports all RESTful operations.

Key Features:

  • Pre-built endpoints for posts, comments, albums, photos, todos, and users
  • Full CRUD operations support
  • No authentication required

Practical Example:

// Using JSONPlaceholder for testing
fetch('https://jsonplaceholder.typicode.com/posts/1')
 .then(response => response.json())
 .then(data => console.log(data));
// Creating a new post
fetch('https://jsonplaceholder.typicode.com/posts', {
 method: 'POST',
 body: JSON.stringify({
 title: 'Test Post',
 body: 'Content for testing',
 userId: 1
 }),
 headers: {
 'Content-type': 'application/json; charset=UTF-8'
 }
});

JSONPlaceholder is especially convenient during early-stage development when the actual backend API is not yet ready. You can build out an entire frontend against JSONPlaceholder’s endpoints and then swap to the real API with a single base URL change.

The service also supports nested resources and filtering, which mimics realistic REST patterns:

// Fetch all comments for a specific post
fetch('https://jsonplaceholder.typicode.com/posts/1/comments')
 .then(r => r.json())
 .then(comments => console.log(comments));
// Filter todos by completion status
fetch('https://jsonplaceholder.typicode.com/todos?completed=false&userId=1')
 .then(r => r.json())
 .then(todos => console.log(todos));

The primary limitation is that writes are not persisted, POST/PUT/DELETE operations return a success response but the data does not actually change on the server. For stateful mocking where created records need to be fetchable afterward, you need either Mockey or a local JSON Server instance.

Best For: Quick prototyping and learning REST APIs without backend setup.

  1. MSW (Mock Service Worker)

While not a Chrome extension, MSW is a powerful library that intercepts requests at the service worker level. It integrates with your development server and provides a more reliable mocking solution than browser extensions.

Key Features:

  • Intercept requests at the network level
  • Works with any testing environment
  • Supports GraphQL mocking
  • Shareable mock definitions

Practical Example:

// MSW setup in your test file
import { http, HttpResponse } from 'msw';
import { setupWorker } from 'msw/browser';
const worker = setupWorker(
 http.get('/api/users', () => {
 return HttpResponse.json([
 { id: 1, name: 'John Doe' },
 { id: 2, name: 'Jane Smith' }
 ]);
 }),
 http.post('/api/users', async ({ request }) => {
 const newUser = await request.json();
 return HttpResponse.json(newUser, { status: 201 });
 })
);
worker.start();

MSW’s real advantage over browser extensions is that the same handler definitions work in Vitest, Jest, and Playwright tests as well as in the browser. Define your mocks once and reuse them everywhere:

// handlers.js - shared between browser and test environments
import { http, HttpResponse } from 'msw';
export const handlers = [
 http.get('/api/products', () => {
 return HttpResponse.json([
 { id: 'p1', name: 'Widget A', price: 19.99, inStock: true },
 { id: 'p2', name: 'Widget B', price: 34.99, inStock: false }
 ]);
 }),
 http.post('/api/cart', async ({ request }) => {
 const item = await request.json();
 return HttpResponse.json({ cartId: 'cart-001', items: [item] }, { status: 201 });
 }),
 // Simulate an auth error
 http.get('/api/admin/dashboard', ({ request }) => {
 const auth = request.headers.get('Authorization');
 if (!auth) {
 return HttpResponse.json({ error: 'Unauthorized' }, { status: 401 });
 }
 return HttpResponse.json({ stats: { users: 142, revenue: 8430 } });
 })
];

// browser.js - development server setup
import { setupWorker } from 'msw/browser';
import { handlers } from './handlers';
export const worker = setupWorker(...handlers);
// node.js - test environment setup
import { setupServer } from 'msw/node';
import { handlers } from './handlers';
export const server = setupServer(...handlers);

MSW also supports network error simulation, which is critical for testing retry logic and error boundaries:

import { http, HttpResponse } from 'msw';
// Test network failure handling
const networkErrorHandler = http.get('/api/critical-data', () => {
 return HttpResponse.error();
});
// In your test
server.use(networkErrorHandler);
// Now assert that your component shows an error state

Best For: Teams who want to include mock definitions directly in their codebase and share them across browser and test environments.

  1. HTTP Toolkit

HTTP Toolkit is a standalone desktop application and browser extension combination that provides deep traffic inspection and interception capabilities. It goes beyond header modification by letting you intercept and rewrite entire requests and responses with a GUI.

Key Features:

  • Full request and response body editing
  • Breakpoint-style interception (pause, edit, resume)
  • Traffic export to HAR format
  • Supports mobile device proxying
  • Open source with a Pro tier for advanced features

HTTP Toolkit is the closest feature-parity alternative to Requestly for developers who need both interception and inspection in a single tool. The breakpoint feature in particular has no equivalent in pure Chrome extensions, it lets you pause a request mid-flight, inspect its full contents, modify it, and then release it to continue:

HTTP Toolkit CLI for automated traffic capture
npx httptoolkit intercept --browser chrome --save-traffic traffic.har

Best For: Developers who need full traffic inspection alongside interception, or who are debugging mobile apps and need to proxy traffic from a device.

Choosing the Right Alternative

Consider these factors when selecting a Requestly alternative:

Use Case Recommended Tool
Header modification only ModHeader
API mocking for frontend Mockey
Environment switching Request Interceptor
Quick prototyping JSONPlaceholder
Team collaboration via code MSW
Full traffic inspection HTTP Toolkit
GraphQL mocking MSW
Testing error states MSW or Mockey

For simple header modifications, ModHeader provides the quickest path to results with zero setup. If you need comprehensive API mocking with response delays and custom status codes, Mockey offers excellent functionality directly in the browser. For teams working on larger projects, integrating MSW into your codebase provides more maintainable and version-controlled mocks that work in CI pipelines.

Migration Tips from Requestly

If you are actively migrating away from Requestly, the process depends on which features you used most.

For redirect rules: Export your Requestly rules as JSON before canceling your subscription. Request Interceptor and HTTP Toolkit both accept JSON rule configurations that map closely to Requestly’s format, though you will need to adapt field names manually.

For header modification rules: These translate directly into ModHeader profiles. Create one ModHeader profile per Requestly rule group you were using.

For mock responses: If your mocks were simple static JSON, Mockey can replace them immediately. If you had complex conditional responses or stateful mocks, MSW is the better migration target and the handlers you write will be more maintainable long-term than extension-based mocks.

For request blocking: Chrome DevTools Network panel has a built-in request blocking feature under the Network tab settings that handles many blocking use cases without any extension.

Practical Workflow: Combining Tools

For many developers, using a combination of tools works best rather than finding a single replacement for everything Requestly did.

A typical development workflow might look like this:

  1. Use ModHeader for persistent auth headers during active development sessions, add your JWT token once and forget about it.
  2. Use MSW in your component tests and Storybook stories so UI states are deterministic regardless of backend availability.
  3. Use JSONPlaceholder when you need to quickly demonstrate a concept or prototype a new page that does not have a real endpoint yet.
  4. Use HTTP Toolkit when you are debugging a specific request that is behaving unexpectedly and you need to inspect the full payload, headers, and timing in one place.

This layered approach means you are never dependent on a single tool’s pricing changes or feature limitations.

Conclusion

The Requestly alternatives listed above provide solid options for developers in 2026. Each tool has strengths in specific areas, so evaluate your primary needs, whether it is header manipulation, API mocking, or environment switching, before committing to one solution.

MSW stands out as the most future-proof choice for teams because mock definitions live in version control alongside application code. Browser extensions are faster to set up for individual tasks but create invisible dependencies that can trip up new team members or break when switching browsers. Choosing the right tool means matching the tool’s scope to the problem you are actually solving day to day.

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