# Mailboxer - a standalone tool that helps developers statically rule out type and communication errors - prototype sandbox now available

**URL:** <https://erlangforums.com/t/mailboxer-a-standalone-tool-that-helps-developers-statically-rule-out-type-and-communication-errors-prototype-sandbox-now-available/5126>\
**Category:** Chat / Discussions\
**Tags:** code-beam-europe, static-typing, mailbox-types, mailboxer, erlang\
**Created:** [October 7, 2025, 4:00pm UTC](https://erlangforums.com/t/mailboxer-a-standalone-tool-that-helps-developers-statically-rule-out-type-and-communication-errors-prototype-sandbox-now-available/5126 "2025-10-07T16:00:22Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![duncanatt](https://erlangforums.com/user_avatar/erlangforums.com/duncanatt/32/309_2.png) [@duncanatt](https://erlangforums.com/u/duncanatt)\
**Post date:** [October 7, 2025, 4:00pm UTC](https://erlangforums.com/t/mailboxer-a-standalone-tool-that-helps-developers-statically-rule-out-type-and-communication-errors-prototype-sandbox-now-available/5126/1 "2025-10-07T16:00:22Z")

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Mailboxer is a new, standalone tool that helps developers statically rule out type and communication errors in actor-based programs.

It builds on Mailbox Types, a new behavioural typing approach for actor languages such as Erlang and Elixir. By adding type annotations to their code using **standard** language constructs, developers can use Mailboxer to detect and rule out:

- Typos in message tags
- Mismatched message payload types
- Unreceived or unexpected messages
- Self-deadlocks

Mailboxer’s annotations naturally document the process-level API, complementing function-level documentation supported by tools like Dialyzer.

* * *

⌨ Try the prototype and explore some example programs: [https://www.dcs.gla.ac.uk/stardust/MailboxerDemo](https://www.dcs.gla.ac.uk/stardust/MailboxerDemo).

📺 Learn more about Mailbox Types and Mailboxer:

[![](https://img.youtube.com/vi/bk0CW1zTano/maxresdefault.jpg "Mailboxer:Early Detection of Erlang Communication Errors- Phil Trinder & Duncan P. Attard |Code BEAM") ](https://www.youtube.com/watch?v=bk0CW1zTano)

The STARDUST Team:  
Duncan Attard, Simon Fowler, Simon Gay, Danielle Marshall, Phil Trinder, and Laura Voinea

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**Author:** ![ieQu1](https://erlangforums.com/user_avatar/erlangforums.com/iequ1/32/2633_2.png) [@ieQu1](https://erlangforums.com/u/ieQu1)\
**Post date:** [October 14, 2025, 10:39am UTC](https://erlangforums.com/t/mailboxer-a-standalone-tool-that-helps-developers-statically-rule-out-type-and-communication-errors-prototype-sandbox-now-available/5126/2 "2025-10-14T10:39:09Z")

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Hello,

Interesting project, thanks for sharing. Just FYI, there is a dead link on [this page](https://www.dcs.gla.ac.uk/stardust/MailboxerDemo/mailboxer-examples): [What is Mailboxer?](https://www.dcs.gla.ac.uk/mailboxer) leads to 404.

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**Author:** ![duncanatt](https://erlangforums.com/user_avatar/erlangforums.com/duncanatt/32/309_2.png) [@duncanatt](https://erlangforums.com/u/duncanatt)\
**Post date:** [October 15, 2025, 6:43am UTC](https://erlangforums.com/t/mailboxer-a-standalone-tool-that-helps-developers-statically-rule-out-type-and-communication-errors-prototype-sandbox-now-available/5126/3 "2025-10-15T06:43:07Z")

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Thank you for taking the time to go through the website and for spotting the dead link! We’ll get that fixed.

Let us know if you have further comments 🙂