The pure asynchronous runtime for Scala
C-Rank Grade: A (Welcoming) - 59/100
External PR Merge Rate: 62%
Response Time: -
First Timer Success: 40%
typelevel/cats-effect has a recorded first-timer success rate of 40.0%. Repositories ranked A typically provide actionable feedback during code reviews and actively nurture new community contributors.
Maintainers in typelevel/cats-effect respond to incoming external pull requests in approximately 0.0 hours on average. Keeping PRs focused on single tasks and ensuring tests pass helps maintainers review faster.
The C-Rank™ system evaluates GitHub projects on a 0–100 scale using real data: PR merge rates, review turnaround time, active maintainer presence, and first-time contributor success. A score of 59.2 places typelevel/cats-effect in the A tier.
The external contributor pull request merge rate for typelevel/cats-effect is 61.8%, based on public PR activity from non-core contributors.
typelevel/cats-effect currently has 1 active issue(s) tagged with beginner-friendly labels like "good first issue", "beginner", or "up-for-grabs".
Balanced & professional review environment in typelevel/cats-effect. Maintains strict focus on technical quality and test standards.
Average Response Latency
Tracks hours until a maintainer leaves a review, comment, or PR response.
External Acceptance Rate
Percentage of community pull requests successfully merged into main.
First PR Conversion
Rate at which developers submitting their first repository PR succeed.
Show contributors that your repository actively reviews and merges external pull requests.
[](https://getmerged.abhishekco.de/typelevel/cats-effect?utm_source=github&utm_medium=badge)
Historical health & responsiveness evolution
External PR acceptance
First PR success rate
50% receive response in
90% receive response in
Maintainer review activity heatmap & prime window prediction
Calculating local time...
Calculating local time...
Detected: UTC
Maintainers are most responsive around 15:00 UTC (15:00 UTC in your timezone). Recommended submission window is Monday - Wednesday from 18:00 to 22:00 UTC (18:00 - 22:00 UTC local).
Maintainer Strategy: Maintainer Sweet Spot: PRs under 150 lines merge in ~16 hours (77% approval). Large PRs (>500 lines) take ~115 hours (28% approval). Keep your diff compact for rapid review.
Some of the docs mention "semantic blocking" and some "fiber blocking". In https://typelevel.org/cats-effect/docs/thread-model we mention "Fiber blocking (previously "Semantic Blocking")". So likely we should review and change all instances of "semantic blocking" to "fiber blocking".
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Rate your first-hand PR experience (review speed, maintainer responsiveness, and onboarding ease) to help other contributors.
When evaluating whether to contribute to typelevel/cats-effect, response velocity and maintainer engagement are crucial. GetMerged continuously tracks pull request trajectories, first-comment latency, and code review rounds to help developers avoid submitting pull requests to backlogged repositories.
Currently, maintainers of typelevel/cats-effect acknowledge new external contributions in approximately -. Out of all submitted pull requests from non-core authors in the last 180-day window, 61.8% were successfully merged into the primary branch.
typelevel/cats-effect has a recorded first-timer success rate of 40.0%. Repositories ranked Welcoming typically provide actionable feedback during code reviews and actively nurture new community contributors.
The initial maintainer response time averages ~-. Keeping PRs scoped to single concerns and ensuring CI checks succeed will optimize review turnaround.
The C-Rank™ index scores repositories on a 0 to 100 scale using an objective formula: external PR merge rates, initial response speed, active maintainer count, and first-time contributor retention. A score of 59.2 places typelevel/cats-effect in the Welcoming tier.
The external pull request merge rate is 61.8%. GetMerged isolates non-core community contributions so external developers get an accurate benchmark of PR acceptance probability.
Yes, typelevel/cats-effect currently has 1 active issue(s) tagged with beginner-friendly labels. You can inspect these directly from the repository issues tab.
All metrics displayed for typelevel/cats-effect are automatically retrieved via the public GitHub API and recalculated daily. Insider pull requests submitted by repository owners or organization members are excluded from merge rate calculations to preserve objective external contributor statistics.