Dev tools · alternatives · 2026

24 alternatives to InboxSDK

First usable API to write Gmail Apps for 1B active users

InboxSDK is a developer tool that provides an API for building applications that integrate with Gmail. It enables developers to create and deploy custom functionality for Gmail's billion active users without requiring… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. InboxSDK launched in 2015; newer entries below may have overtaken it.

1. 1OS
   Open-Sourcing InboxSDK (YC S11) – Build Apps in Gmail▲257

   Hi HN! We’re Aleem, Chris, Borys, Meichen and Zach from Streak (YC S11) and today we’re open sourcing our InboxSDK https://www.inboxsdk.com, which makes it easy to build apps for Gmail. Over 1.8B users spend their days in Gmail! Having your app built into the Gmail workflow is a better user experience and gives you great user retention. InboxSDK gives you a high-level, declarative API to insert your UI into Gmail without having to directly manipulate the DOM yourself. End users install a browser extension to use your app. The SDK can add UI to multiple areas of Gmail. For example,…

   2022 · its alternatives →

2. 2
   Inbox by Google▲1,147

   Next generation inbox

   2014 · google.com · its alternatives →

3. 3
   InboxSDK by Streak (YC S11) – Build Apps inside Gmail▲176

   The InboxSDK is high level Javascript library used to easily build browser extensions that interact with Gmail

   2015 · inboxsdk.com · its alternatives →

4. 4
   Inboxer▲212

   A clean, open-source desktop client for Google Inbox 💌

   2018 · denysdovhan.com · its alternatives →

5. 5
   New Gmail▲935

   The new version of Gmail web

   2018 · blog.google · its alternatives →

6. 6
   InboxPro▲174

   Boost your productivity & turn Gmail into a powerful machine

   2022 · inboxpro.io · its alternatives →

7. 7
   Inbox Zero Tabs▲398

   Split inbox tabs for Gmail. 100% private. 100% free

   2025 · chromewebstore.google.com · its alternatives →

8. 8
   Gmail API▲170

   Flexible, RESTful access to the user's inbox

   2014 · developers.google.com · its alternatives →

9. 9
   Superinbox▲531

   Email vibing in your Gmail / Outlook

   Oct 2025 · superinbox.com · its alternatives →

10. 10
    Templates for Gmail▲495

    Create & customize Gmail templates that live in your inbox 💌

    2017 · templatesforgmail.com · its alternatives →

11. 11
    Mimestream, a native macOS email client for Gmail▲403

    A native macOS email client for Gmail

    2020 · mimestream.com · its alternatives →

12. 12
    Mailflow▲267

    Run your business from Gmail

    2020 · getmailflow.com · its alternatives →

13. 13
    Boxy▲572

    Inbox by Gmail, finally on your Mac

    2015 · boxyapp.co · its alternatives →

14. 14
    Gmail.js – JavaScript API for Gmail▲212

    Gmail JavaScript API. Contribute to KartikTalwar/gmail.js development by creating an account on GitHub.

    2013 · github.com · its alternatives →

15. 15
    GMass▲580

    Send email marketing campaigns INSIDE Gmail.

    2017 · gmass.co · its alternatives →

16. 16
    Gmail in the Gemini Era▲371

    Ask your inbox anything to get summaries, drafts, & more

    Jan 2026 · blog.google · its alternatives →

17. 17
    Signal – Edit emails in your Gmail inbox▲151

    2013 · trysignal.com · its alternatives →

18. 18
    Hello Inbox▲283

    Hey HN, I built an email deliverability SaaS with a RAG system. It's trained on all my knowledge and hundreds of real deliverability use cases from 4+ years experience as an Email Deliverability Specialist on Upwork. It solves a frustration problem a lot of businesses are experiencing. I'm looking for feedback so let me know in the comments.

    Aug 2026 · helloinbox.email · its alternatives →

19. 19
    Boxy 2▲301

    The best Mac client for Inbox by Gmail

    2017 · boxyapp.co · its alternatives →

20. 20
    Clean Inbox for Gmail™▲150

    A privacy-oriented Gmail add on against marketing email

    2024 · cleaninboxforgmail.com · its alternatives →

21. 21
    Darwin Mail▲259

    Enhance Gmail to get your Google Inbox features back.

    2019 · darwinmail.app · its alternatives →

22. 22
    MailToDock▲70

    Turn Gmail into Google Tasks with AI-powered

    Apr 2026 · mailtodock.vercel.app · its alternatives →

23. 23
    Drag Pro▲305

    Transform Gmail into organized To Do lists (like Trello)

    2018 · dragapp.com · its alternatives →

24. 24
    Mailazy▲203

    Cloud email infrastructure for the internet

    2022 · mailazy.com · its alternatives →

Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →