---
title: "Meet Duck Typer: your new duck typing friend"
url: https://daily.dev/posts/meet-duck-typer-your-new-duck-typing-friend-bkn7wnfxf
source_url: https://thoughtbot.com/blog/meet-duck-typer-your-new-duck-typing-friend
type: article
source: "RUBYLAND"
published: 2026-03-23T00:24:39.225Z
updated: 2026-03-23T00:25:09.801Z
tags: ["testing", "ruby"]
reading_time: 4
upvotes: 0
comments: 0
language: en
---

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# Meet Duck Typer: your new duck typing friend

**[RUBYLAND](https://daily.dev/sources/rubyla)** · 4 min read · 0 upvotes · 0 comments

## Summary

duck_typer is a new Ruby gem from Thoughtbot that enforces duck-typed interfaces through tests without requiring type annotations. It provides test helpers (for both Minitest and RSpec) that compare the public method signatures of multiple classes, catching missing methods, signature drift, and mismatched keyword arguments. You can check full or partial interfaces, name them, target class methods, and even auto-discover classes by namespace so new implementations are automatically validated.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://thoughtbot.com/blog/meet-duck-typer-your-new-duck-typing-friend>

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---

Tags: [#testing](https://daily.dev/tags/testing), [#ruby](https://daily.dev/tags/ruby)

[View this post on daily.dev](https://daily.dev/posts/meet-duck-typer-your-new-duck-typing-friend-bkn7wnfxf)