> ## Content Index
> Fetch the complete content index at: https://itsfoss.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# Slack Open Sources 'Hakana' to Help Developers With Hack Language
- URL: https://itsfoss.com/news/slack-open-source-hakana/
- Published: 2023-02-28T10:03:24.000Z
- Updated: 2023-02-28T10:03:24.000Z
- Description: Slack open sources its internal tool Hakana to help other developers and companies using Hack language.
- Author: Sourav Rudra
- Tags: Open Source, News, #Import 2025-11-08 21:15

Slack, the popular team communication and collaboration platform, has recently open-sourced its '**Hakana**' type checker, a tool they created for internal use.

This move comes at a time when a good deal of proprietary software is being open-sourced.

**Related Read** 📖

[DreamWorks’ Renderer Used for ‘Puss in Boots’ is Going Open-Source Very SoonDreamWork animation company is making its in-house renderer open-source very soon!![](https://itsfoss.com/content/images/size/w256h256/2022/08/android-chrome-192x192.png)It's FOSS NewsSourav Rudra![](https://itsfoss.com/content/images/2023/02/dreamworks-opensourced-renderer-moonray.png)](https://itsfoss.com/dreamworks-moonray-open-source/)

**What is it?:** Hakana is a static analysis tool for the [Hack](https://hacklang.org/?ref=itsfoss.com) programming language that uses [Psalm](https://psalm.dev/?ref=itsfoss.com) as a base and is written in [Rust](https://www.rust-lang.org/?ref=itsfoss.com).

In simpler terms, it is **a tool that provides type checking for Hack** by running several analytical methods.

Currently, Slack is using it to detect issues in their Hack code; they migrated from PHP to Hack in 2016 [citing](https://slack.engineering/taking-php-seriously/?ref=itsfoss.com) various inconsistencies with it.

Some of Hakana's abilities include:

- Prevents unused functions and private methods.
- Prevents unused assignments inside closures.
- Ability to detect impossible and redundant type-checks.
- Can warn about potential SQL injection attacks and cross-site scripting vulnerabilities.
- Prevents misuse of internal Slack APIs (via Plugin hooks).

Slack mentions more of its use cases as:

> We also use Hakana to automate type-aware API migrations (again via plugin hooks) and to delete unused functions in bulk. Thanks to Rust, those whole-codebase migrations are relatively quick.

Furthermore, Hakana **investigates how data moves between functions** in a codebase and tries to verify whether any attacker-controlled data shows up in places it shouldn't.

It also has a [web version](https://hakana.dev/?ref=itsfoss.com) that can be accessed via web browsers using [WASM](https://webassembly.org/?ref=itsfoss.com), thanks to it being written in Rust.

Slack lists a couple of reasons **why they decided to open-source Hakana**:

- The broader programming language community may be able to help, especially in the case of security analysis.
- This serves to repay the favor to Psalm, the tool on which Hakana is based.
- They expect companies with massive PHP codebases to benefit from Hakana by forking and altering it to suit their needs.

💡

Only a few companies use Hack language because of its '**high switching costs**', meaning if a company decides to migrate to Hack from PHP, a lot of their server infrastructure will need a change too.

I suggest you go through the [announcement blog](https://slack.engineering/hakana-taking-hack-seriously/?ref=itsfoss.com) if you are interested to learn more about the technical bits of Hakana.

**Suggested Read** 📖

[Ditch Slack With These Open Source Team Chat ToolsHere, we shall take a look at the best open source slack alternatives that you can choose to communicate with your team at work.![](https://itsfoss.com/content/images/size/w256h256/2022/12/android-chrome-192x192.png)It's FOSSAnkush Das![](https://itsfoss.com/content/images/wordpress/2020/02/Open-Source-Team-Communication-Software.jpg)](https://itsfoss.com/open-source-slack-alternative/)