Vaadin Flow is a Java framework binding Vaadin web components to Java. This is part of Vaadin 10+.
C-Rank Grade: A (Welcoming) - 67/100
External PR Merge Rate: 82%
Response Time: 2d
First Timer Success: 53%
vaadin/flow has a recorded first-timer success rate of 52.9%. Repositories ranked A typically provide actionable feedback during code reviews and actively nurture new community contributors.
Maintainers in vaadin/flow respond to incoming external pull requests in approximately 50.4 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 66.9 places vaadin/flow in the A tier.
The external contributor pull request merge rate for vaadin/flow is 81.6%, based on public PR activity from non-core contributors.
vaadin/flow currently has 1 active issue(s) tagged with beginner-friendly labels like "good first issue", "beginner", or "up-for-grabs".
Highly welcoming maintainers in vaadin/flow. Prompt code reviews with positive guidance for new contributors.
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/vaadin/flow?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
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Detected: UTC
Maintainers are most responsive around 10:00 UTC (10:00 UTC in your timezone). Recommended submission window is Wednesday - Friday from 07:00 to 11:00 UTC (07:00 - 11:00 UTC local).
Maintainer Strategy: Maintainer Sweet Spot: PRs under 150 lines merge in ~33 hours (96% approval). Large PRs (>500 lines) take ~242 hours (37% approval). Keep your diff compact for rapid review.
Description of the bug Currently you can't add e.g. a List<TextField> directly, you need unsafe casts or unnecessary copying. Expected behavior By changing the signature to default void add(Collection<? extends Component> components) the issue is solved. The only "downside" is that implementations won't be able to (safely) add to the collection as they don't know the exact type of collection, but they shouldn't modify the collection anyway. Minimal reproducible example This doesn't compile: List<TextFields> fields = List.of(field1, field2, field3); var div = new Div(); div.add(fields); Versions Currently using Vaadin 25, but I believe this applies to all Flow versions.
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When evaluating whether to contribute to vaadin/flow, 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 vaadin/flow acknowledge new external contributions in approximately 2 days+. Out of all submitted pull requests from non-core authors in the last 180-day window, 81.6% were successfully merged into the primary branch.
vaadin/flow has a recorded first-timer success rate of 52.9%. Repositories ranked Welcoming typically provide actionable feedback during code reviews and actively nurture new community contributors.
The initial maintainer response time averages ~2 days+. 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 66.9 places vaadin/flow in the Welcoming tier.
The external pull request merge rate is 81.6%. GetMerged isolates non-core community contributions so external developers get an accurate benchmark of PR acceptance probability.
Yes, vaadin/flow 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 vaadin/flow 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.