Challenges
Open Source Challenges
Hands-on challenges built around real open source tools. Filter by technology, work through real-world scenarios, and learn by doing, entirely in your browser.
Spring Boot Challenges· 3 results
Beginner
Stand up the Lab
- How an OpenFeature client and provider work together: the SDK is provider-agnostic and the flagd provider plugs in via dependency only
- What remote provider means in practice: the SDK calls a separate flag service (flagd) over gRPC, not parsing flags.json itself
- What flags.json looks like for flagd (state, variants, defaultVariant)
ChallengeBlind by Design
Intermediate
Outcome by Cohort
- How OpenFeature's transaction-context propagation works in a thread-per-request server, and why a ThreadLocalTransactionContextPropagator is the right primitive for Servlet-based apps
- The difference between request-scoped context (the subject's species) and global evaluation context (the trial's country), and when each is the right tool
- How hooks let you attach cross-cutting behaviour, audit logging today and OpenTelemetry tracing tomorrow, without modifying every flag evaluation call site
ChallengeBlind by Design
Expert
Read the Chart
- How the OpenFeature OpenTelemetry hooks (TracesHook and MetricsHook) join flag evaluations to the rest of an application's telemetry without a separate ingestion path
- How to author your own Hook: a tiny class that copies merged-eval-context attributes onto the active OTel span, closing the loop between why a flag resolved the way it did and what the operator sees in Tempo
- How fractional rollout in flagd buckets users by targetingKey (same key, same bucket, every request) and how to read that bucketing off a dashboard
ChallengeBlind by Design
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