Software Alternatives, Accelerators & Startups

Requestly VS Sizzy

Compare Requestly VS Sizzy and see what are their differences

Requestly logo Requestly

A Powerfulย API Mockingย andย Testingย Tool

Sizzy logo Sizzy

The browser for designers and developers
  • Requestly Requestly
    Requestly //
    2025-02-12
  • Requestly Rest Client
    Rest Client //
    2025-02-12
  • Requestly HTTP Interceptor
    HTTP Interceptor //
    2025-02-12
  • Requestly API Mocking
    API Mocking //
    2025-02-12
  • Requestly Requestly
    Requestly //
    2025-02-12

Requestly is a modern and powerful companion for API Development and Testing. It is an open-source tool purpose-built to speed up and simplify API development workflow for developers and QAs. It is a combination of API Client and HTTP Interceptor that helps create and share API Contracts, testing APIs, and easily mock and integrate them into web and mobile apps.

  • Sizzy Landing page
    Landing page //
    2023-04-23

Requestly

$ Details
freemium
Platforms
Google Chrome Firefox Edge Safari Brave Opera Vivaldi Android Windows Linux Mac OSX MacOS
Release Date
2021 January
Startup details
Country
United States
State
California
Founder(s)
Sachin Jain, Sagar Soni, Sahil Gupta
Employees
20 - 49

Sizzy

Website
sizzy.co
Pricing URL
-
$ Details
paid $7.0 / Monthly
Platforms
-
Release Date
-

Requestly features and specs

  • Redirect URL
  • Block Network Requests
  • Modify Request & Response Header
  • Modify Response
  • Supercharge Selenium
  • Session Replay
  • Modify Query Params
  • Team Workspace
  • API Client
  • API Mocks
  • GraphQL Support
  • Zero Setup
  • Auto Capture Sessions
  • Network Logs
  • Console Logs

Sizzy features and specs

  • Browser Synchronization
    Sizzy allows developers to test their web applications simultaneously across multiple devices and viewports, keeping them in sync with one another. This feature helps ensure a consistent user experience across different devices.
  • Development Tools Integration
    Sizzy provides seamless integration with popular web development tools and browsers, making it easier for developers to debug and test their applications without switching between different environments.
  • Customizable Viewports
    Users can customize the viewport sizes to match various devices. This flexibility helps developers test how their application looks and behaves on a wide range of screens and resolutions.
  • Live Reload
    The live reload feature automatically updates the view as developers make changes to the code, improving development speed and reducing the time spent on manual refreshes.
  • Collaboration Features
    Sizzy offers collaboration features that allow teams to share their screen setups and sync states with team members, improving communication and feedback during the development process.

Possible disadvantages of Sizzy

  • Subscription Cost
    Sizzy operates on a subscription-based pricing model, which might be a barrier for individual developers or small teams with limited budgets.
  • System Resource Intensive
    Running multiple viewports simultaneously can be resource-intensive and may slow down the development machine, especially if it lacks robust hardware specifications.
  • Learning Curve
    New users might encounter a learning curve to fully utilize all the features Sizzy offers, particularly if they are accustomed to traditional development environments.
  • Dependency on Internet Connection
    Some features of Sizzy may require an active internet connection. This dependency could be a limitation in environments with unstable or limited internet access.
  • Limited Offline Capabilities
    Sizzy's functionality is somewhat limited when offline, reducing its effectiveness for developers who prefer or need to work in environments with intermittent internet access.

Analysis of Requestly

Overall verdict

  • Requestly is generally regarded as a good tool due to its comprehensive functionalities and ease of use. Its ability to seamlessly manage network requests makes it suitable for both beginners and experienced developers.

Why this product is good

  • Requestly is widely considered a valuable tool because it offers robust and flexible features for intercepting and modifying network requests. Developers and QA testers appreciate it for its ability to simulate and debug API calls efficiently. It is particularly useful for testing changes without altering the codebase and for working with web applications in development and production environments.

Recommended for

  • Developers looking to debug and test API endpoints.
  • Quality Assurance (QA) teams that require reliable testing tools for web applications.
  • Technical professionals who manage network traffic and need to modify or redirect requests effortlessly.
  • Anyone involved in web development who needs to simulate network conditions or test application behavior under different scenarios.

Analysis of Sizzy

Overall verdict

  • Sizzy is considered to be a beneficial tool for web developers due to its convenience and wide range of features tailored specifically to enhance the development experience. However, the final verdict may depend on individual needs and preferences, including the specific features one seeks in a development tool.

Why this product is good

  • Sizzy is a browser specifically designed for web developers to test their projects. It offers features such as simultaneous multi-device viewing, built-in developer tools, responsive design testing, and collaboration features. These features help streamline the development process by allowing developers to easily spot layout issues, test mobile responsiveness, and ensure cross-browser compatibility all in one app.

Recommended for

  • Web developers looking for efficient responsive design testing.
  • Teams who need collaboration features integrated with their development tools.
  • Developers who manage multiple viewports and devices during the web development process.
  • Individuals seeking a centralized tool to streamline web testing and debugging.

Requestly videos

Session Replays by Requestly

More videos:

  • Demo - Get Started with Requestly
  • Tutorial - Modify API Response using Requestly Chrome Extension
  • Tutorial - How to load local JS file in production sites for faster debugging (Map Local Tool)
  • Tutorial - Report Quality Bugs with Video, Network logs, Console logs & Environment details

Sizzy videos

Should every Frontend Developer own this software? Checking out 'Sizzy'

More videos:

  • Review - Demo โ€“ First impressions of sizzy.app
  • Review - SHADOWHUNTERS | CASTING CLARY & SIZZY

Category Popularity

0-100% (relative to Requestly and Sizzy)
Developer Tools
62 62%
38% 38
Testing
100 100%
0% 0
Website Testing
0 0%
100% 100
APIs
100 100%
0% 0

Questions & Answers

As answered by people managing Requestly and Sizzy.

Who are some of the biggest customers of your product?

Requestly's answer

  • Verizon
  • AT&T
  • Adobe
  • Salesforce
  • Telegraph
  • Intuit
  • Verizon

How would you describe the primary audience of your product?

Requestly's answer

Front-end developers, QAs, PMs, Digital Marketers

What makes your product unique?

Requestly's answer

Requestly is an open-source API development and testing tool that combines the capabilities of an API Client and HTTP Interceptor, making it a better alternative to Postman + Charles Proxy. It simplifies API mocking, request modification, and debugging with an intuitive no-code interface, enabling developers and QAs to test APIs efficiently.

User comments

Share your experience with using Requestly and Sizzy. For example, how are they different and which one is better?
Log in or Post with

Reviews

These are some of the external sources and on-site user reviews we've used to compare Requestly and Sizzy

Requestly Reviews

Comparing Charles Proxy, Fiddler, Wireshark, and Requestly
On the pricing front, Requestly strikes a balance between affordability and functionality. It is an open-source tool, offering freemium to individual developers and affordable pricing plans for team collaboration. We have also clearly differentiated how Requestly differs from Wireshark and other web debugging tools like Proxyman, Modheader, and HTTP ToolKit separately.
Source: dev.to

Sizzy Reviews

We have no reviews of Sizzy yet.
Be the first one to post

Social recommendations and mentions

Based on our record, Requestly should be more popular than Sizzy. It has been mentiond 35 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

Requestly mentions (35)

  • Why You Need a Local-First API Client (With Hands-On Example)
    If you want to try a local-first workflow, you can start using Requestly here: https://requestly.com. - Source: dev.to / 8 months ago
  • How to use Cursor to Generate API Testcases in Requestly
    Thatโ€™s where automation changes the game. By pairing Cursor, an AI-powered coding assistant, with Requestly's local-first API testing and mocking platform, you can offload the grunt work of writing tests to AI while keeping execution secure and reproducible on your own system. In this article, weโ€™ll walk through how to set up Cursor with Requestly, generate test cases automatically, and run them end-to-end so that... - Source: dev.to / 8 months ago
  • These 20 Awesome API Clients Will Change How You Work with APIs
    Requestly is a versatile browser extension and web client used to intercept, mock, and debug APIs in real-timeโ€”perfect for frontend developers. - Source: dev.to / about 1 year ago
  • Best Tools for GraphQL Development in 2025
    Requestly is a powerful tool for modifying GraphQL responses, intercepting requests, and debugging API interactions. It allows developers to tweak request bodies, capture GraphQL traffic, and share sessions for easier debugging and collaboration. - Source: dev.to / over 1 year ago
  • How Not to Use AI in Software Development
    Learn more at https://requestly.com/. - Source: dev.to / over 1 year ago
View more

Sizzy mentions (19)

View more

What are some alternatives?

When comparing Requestly and Sizzy, you can also consider the following products

Postman - The Collaboration Platform for API Development

Polypane - The browser for ambitious web developers that want to 5ร— their quality and efficiency.

Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.

Browsershots - Browsershots makes screenshots of your web design in different browsers.

ngrok - ngrok enables secure introspectable tunnels to localhost webhook development tool and debugging tool.

Sauce Labs - Test mobile or web apps instantly across 700+ browser/OS/device platform combinations - without infrastructure setup.