Cosmo Feature Flags: Foundations

Create, compose, and enable a feature flag to roll out schema changes gradually and safely.

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Details

  • Updated: Jul 2026
  • Lessons: 7
  • Duration: ~30 minutes
  • Level: Beginner

Prerequisites

  • None.

What you'll learn

  • How feature flags work in GraphQL Federation
  • Feature subgraphs, base subgraphs, and how to compose them into a feature flag
  • Benefits: including incremental rollout, schema evolution, dynamic config, and staging
  • Plan a safe 0% → 100% gradual rollout and retire the flag afterwards

Who may benefit from this course

  • Backend and platform engineers who want a quick introduction to feature flags
  • Teams that want to ship schema changes to a subset of clients before everyone
  • Anyone migrating a service and wanting a safe, reversible rollout path
  • Developers who learn best by running the commands themselves