Repository Issues

typelevel/cats

Lightweight, modular, and extensible library for functional programming.

View on GitHub
Stars
 (5,438 stars)
Forks
 (1,241 forks)
Indexed issues
 (9 indexed issues)
open beginner issues
 (9 open beginner issues)
Latest indexed
Aug 14, 2026
Last GitHub push
May 11, 2026
License
Other
Contributing guide
Contributing guide
Code of conduct
Code of conduct
Dominant language
Scala
PR merge metrics
 (Avg merge 4h 2m) (5 merged PRs in 30d)
Beginner labels
help wantedgood first issue

Issues

9 open indexed issues

Open
Make `Hash.fromUniversalHashCode` null safe
good first issue
Why recommendedHas a beginner-friendly label · Contributing guide available
Has a beginner-friendly labelContributing guide available

typelevel / cats · #4831 · Feb 22, 2026 · Scala · 5,438 stars

6 comments1 reaction1 assignee
Open
typeclass-based collections implementations
enhancementhelp wanted
Why recommendedNo assignee yet · Has a beginner-friendly label
No assignee yetHas a beginner-friendly labelContributing guide available

typelevel / cats · #4147 · Mar 9, 2022 · Scala · 5,438 stars

28 comments2 reactions0 assignees
Open
Clean out warnings from Dotty
good first issuelsug
Why recommendedNo assignee yet · Has a beginner-friendly label
No assignee yetHas a beginner-friendly labelContributing guide available

typelevel / cats · #3751 · Jan 30, 2021 · Scala · 5,438 stars

2 comments0 reactions0 assignees
Open
Add a documentation page on error handling
documentationhelp wanted
Why recommendedNo assignee yet · Has a beginner-friendly label
No assignee yetHas a beginner-friendly labelContributing guide available

typelevel / cats · #3523 · Jul 16, 2020 · Scala · 5,438 stars

8 comments3 reactions0 assignees
Open
Add `attemptOption` to Alternative
help wantedlow-hanging fruit
Why recommendedNo assignee yet · Has a beginner-friendly label
No assignee yetHas a beginner-friendly labelContributing guide available

typelevel / cats · #2936 · Jul 9, 2019 · Scala · 5,438 stars

6 comments0 reactions0 assignees
Open
Improve doc for Func
documentationgood first issuehelp wantedlow-hanging fruitscope: small
Why recommendedHas a beginner-friendly label · Contributing guide available
Has a beginner-friendly labelContributing guide available

typelevel / cats · #2650 · Nov 30, 2018 · Scala · 5,438 stars

8 comments0 reactions1 assignee
Open
Add doctests (excellent first-time issue)
documentationgood first issuehelp wanted
Why recommendedNo assignee yet · Has a beginner-friendly label
No assignee yetHas a beginner-friendly labelContributing guide available

typelevel / cats · #2479 · Sep 7, 2018 · Scala · 5,438 stars

14 comments0 reactions0 assignees
Open
Style scaladoc slightly
documentationgood first issuehelp wanted
Why recommendedNo assignee yet · Has a beginner-friendly label
No assignee yetHas a beginner-friendly labelContributing guide available

typelevel / cats · #1835 · Aug 21, 2017 · Scala · 5,438 stars

2 comments0 reactions0 assignees