
Superhuman
Mailo
Soverin
Horde
ProtonMail
Mailpile
Teknik Mail
Email at its best, new from Basecamp.

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, HEY seems to be more popular. It has been mentioned 24 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | hey.com | diffyn.com |
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What each product offers, as listed by its team.


Possible disadvantages
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
Overall verdict
Why this product is good
Recommended for
Walkthroughs and reviews on video.
Hey Review: Why this $99 per year email is Superhuman's Most Exciting Challenger | Keep Productive
More videos
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 HEY 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.
Share your experience with using HEY and Diffyn. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


Apple apparently told ProtonMail "out of the blue" that it was required to add an in-app purchase option to stay in the App Store. Similar to the situations with HEY and Wordpress earlier this year, ProtonMail had a...
We have no reviews of Diffyn yet. Be the first one to post
Recommendations tracked on public social media and blogs since March 2021.


Seven gems to manage background jobs. The team looked at what they were running and said "this can't be right." That became the brief for Solid Queue. Rosa got picked for the project, built it in production at Hey first, iterated on it... - Source: dev.to / 3 months ago
Basecamp: After using clouds from both Amazon and Google extensively over the past 15 years, we finally had enough of the outrageous bills and the ever-increasing complexity. So in 2023, we pulled Basecamp, HEY, and five other heritage... - Source: dev.to / about 1 year ago
Attending the latest edition of Rails World and watching the talk by DHH made me realize that generating views on the backend with Rails was no longer synonymous with slow, ugly interfaces that do not care about UX. With Hotwire, through... - Source: dev.to / over 2 years ago
Tracking Diffyn since Jun 2025.
When comparing HEY and Diffyn, you can also consider the following products.


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Secure email with absolutely no compromises. Get your free encrypted email account today.
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Mailpile is a modern, fast web-mail client with user-friendly encryption and privacy features.
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