feat vs GO Feature Flag

feat is a hosted feature-flag platform for early engineering teams. Server SDKs evaluate flags locally, so each flag read does not require a network call; changes stream to connected SDKs in under a second. Targeting rules combine conditions across users, devices, organizations, sessions, and requests using AND and OR. Sticky percentage rollouts keep a user, device, or organization on the same variation across requests and sessions. First-party SDKs are available for Node.js, Bun, Deno, Go, Python, Ruby, browser JavaScript, and Flutter/Dart, with OpenFeature providers for web, Node.js, and Dart. Metric sources include Segment, Mixpanel, PostHog, and custom sources. The Free plan costs nothing and includes 7,500 MAU, 100 server connections, two projects, unlimited environments, and unlimited flags. Starter costs $19 a month, with annual billing listed at $15/mo. Built-in statistical experiments, variant tracking, metric integrations, auto-advance gradual rollouts, and Slack integration are listed as coming in Q3 2026, not current features.

GO Feature Flag is an open-source feature-flag management system built on OpenFeature for infrastructure you control. Its relay proxy runs locally with Docker and a flag configuration file. Teams can target users and segments, use percentage or progressive rollouts, schedule changes, and run A/B tests. Client and server SDKs are listed for 16 languages and frameworks, including JavaScript, TypeScript, React, Swift, Kotlin, Go, Java, Python,.NET, Ruby, Rust, and others. Retrievers load configuration from HTTP(S), local files, Kubernetes ConfigMaps, cloud storage, Git providers, MongoDB, Redis, and PostgreSQL. Exporters send evaluation data to Kafka, AWS S3, BigQuery, OpenTelemetry, webhooks, or logs. Notifications can reach Slack, Discord, Microsoft Teams, webhooks, or logs. The MIT-licensed Opensource plan costs nothing, billed forever, with all features, unlimited flags, and community support.