# WhatsApp releases eqWAlizer - A type-checker for Erlang

**URL:** <https://erlangforums.com/t/whatsapp-releases-eqwalizer-a-type-checker-for-erlang/1704>\
**Category:** Chat / Discussions\
**Tags:** types, erlang-otp, eqwalizer\
**Created:** [August 2, 2022, 6:40pm UTC](https://erlangforums.com/t/whatsapp-releases-eqwalizer-a-type-checker-for-erlang/1704 "2022-08-02T18:40:14Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![DevotionGeo](https://erlangforums.com/user_avatar/erlangforums.com/devotiongeo/32/213_2.png) [@DevotionGeo](https://erlangforums.com/u/DevotionGeo)\
**Post date:** [August 2, 2022, 6:40pm UTC](https://erlangforums.com/t/whatsapp-releases-eqwalizer-a-type-checker-for-erlang/1704/1 "2022-08-02T18:40:14Z")

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> In the last two years at WhatsApp we have developed eqWalizer - a type-checker for Erlang AS IS - in style of Flow, Pyre, Hack. It’s already used in a significant part of our codebase. In this talk we overview the key eqWalizer’s design choices we made and explain the reasons behind them. Moreover, we’ll report about the challenges of using Erlang in large code bases and how static typing has allowed us to scale development through providing fast signal to developers. Finally, we’ll also present the lessons learned from enabling static typing for the code underpinning the largest messaging app in the world.

> **[eqWAlizer - Scaling Erlang development at WhatsApp with static typing (Erlang...](https://icfp22.sigplan.org/details/erlang-2022-papers/6/eqWAlizer-Scaling-Erlang-development-at-WhatsApp-with-static-typing)**
>
> General Information 
> Welcome to the website of the Erlang 2022 workshop! 
> Series 
> Erlang 2022 is the 21st ACM SIGPLAN Erlang Workshop, and is a satellite event of the 27th ACM SIGPLAN International Conference on Functional Programming (ICFP 2022)....

> **[GitHub - WhatsApp/eqwalizer: A type-checker for Erlang](https://github.com/WhatsApp/eqwalizer)**
>
> A type-checker for Erlang. Contribute to WhatsApp/eqwalizer development by creating an account on GitHub.

[https://twitter.com/lambdamix/status/1554435296988504064](https://twitter.com/lambdamix/status/1554435296988504064)