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Feather Flag is a production-grade feature flag platform that evaluates flags at the edge — your users get sub-millisecond flag resolution, no matter where they are.

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What you can do

  • Control rollouts — enable features for a percentage of users, specific user segments, or everyone at once.
  • Target by attribute — match on any context attribute: userId, country, plan, email, or anything custom.
  • Protect production — lock environments behind a change-request workflow so every flag change gets a human review.
  • Measure impact — built-in usage analytics track evaluation counts, value distributions, and rule match rates per flag per day.

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How it works

Your app  →  Feather Flag SDK  →  Delivery API (edge cache)
                                        ↓
                                  Management API (database)
  1. The SDK fetches a bundled snapshot of all flags for your environment from the Delivery API — one network hop, cached at the edge nearest your user.
  2. The evaluation engine runs entirely in your process: no extra round-trip for each evaluate() call.
  3. Events are flushed asynchronously to the management API for analytics — the hot path never waits on telemetry.

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Next steps

Quickstart

Create a project and evaluate your first flag in under 5 minutes.

Authentication

Learn about API keys and session auth.

Flag Config

Understand the rule engine and targeting model.

API Reference

Full reference for every endpoint.