# Erlang Blog Post: Introducing Rebar3 TypEr - NextRoll

**URL:** <https://erlangforums.com/t/erlang-blog-post-introducing-rebar3-typer-nextroll/1353>\
**Category:** Blog Posts\
**Tags:** via-devtalk, blog-post, dev-tools, blogs-by-elbrujohalcon\
**Created:** [April 28, 2022, 6:56am UTC](https://erlangforums.com/t/erlang-blog-post-introducing-rebar3-typer-nextroll/1353 "2022-04-28T06:56:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![elbrujohalcon](https://erlangforums.com/user_avatar/erlangforums.com/elbrujohalcon/32/241_2.png) [@elbrujohalcon](https://erlangforums.com/u/elbrujohalcon)\
**Post date:** [April 28, 2022, 6:56am UTC](https://erlangforums.com/t/erlang-blog-post-introducing-rebar3-typer-nextroll/1353/1 "2022-04-28T06:56:33Z")

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This is what we’ve been doing in our last HackWeek at NextRoll with Mackenzie and @pablocostass  
Now you can add typespecs to your modules using TypEr, with `rebar3 typer`

> **[Introducing Rebar3 TypEr - NextRoll](https://tech.nextroll.com/blog/dev/2022/04/27/rebar3-typer.html)**
>
> And another rebar3 plugin from HackWeek, this time for type specs.