
Postman
Insomnia REST
Hoppscotch
Thunder Client
Katalon
RapidAPI for Mac
Assertible
API Client and API monitoring

The modern platform for creating, sharing, and collaborating on AI prompts. Advanced version control and real-time testing.

Which is more popular?
Based on our record, Testfully seems to be more popular. It has been mentioned 1 time since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | testfully.io | diffyn.com |
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| Company | 2020 | — |
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What each product offers, as listed by its team.


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The Ultimate Prompt Tool for Creators – Visualize & Organize with Diffyn
How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing Testfully and Diffyn.
Diffyn's answer:
Addresses workflow and change management on LLM prompts, provide teams with traceability and visualization of tests across multiple models, provide deeper understading into efficiency of these prompts.
Diffyn's answer:
Diffyn is the platform that specializes on both change management and multi-model analysis.
Diffyn's answer:
React, Next.js, POSTGRESQL
Diffyn's answer:
Professionals incorporating LLMs or AI tools in their workflow and wants to keep track of changes and test their prompts.
Diffyn's answer:
I started working on Diffyn when I notice that prompting has become an essential part of work across many industries. While there are version control platofrms like github, they are not designed for just prompt management are can be overkill such applications, it is also not integrated natively with various LLMs and relevant tools for users to validate ideas and visualise results properly.
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External articles and on-site reviews we used to compare the two products.


Testfully is a collaborative API testing tool that allows teams to define, share, and test APIs efficiently. It focuses on both cloud and offline capabilities.
Moreover, Testfully saves your requests to the cloud, which you can easily share with your teammates. Testfully’s API testing and monitoring features enable you to re-use tests easily and validate the correctness of...
Testfully is available via a web application on any modern browser. You can send requests to both local and deployed Restful and GraphQL APIs and inspect the response. Testfully supports Environments, Configs and...
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Recommendations tracked on public social media and blogs since March 2021.


TL;DR: For AI-native test generation from specs, try Kusho AI. For the most complete platform with the newest AI Agent Mode, go Postman. For open-source and Git-native workflows, Bruno or Hoppscotch are your best bets. Enterprise teams... - Source: dev.to / 7 months ago
Tracking Diffyn since Jun 2025.
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