GO Feature Flag

GO Feature Flag is an open-source flag management system built on OpenFeature. It is best suited to teams that want to run release controls on infrastructure they own and connect flagging to a broad range of application stacks. The free, unlimited-flag offering is unusually capable, while premium support and vulnerability-fix commitments are reserved for enterprise customers.

Overview

The project is released under the MIT license, including permission for commercial use. Its relay proxy can be launched locally with Docker and reads a flag configuration file, so teams can fit it into infrastructure they already operate rather than adopt a separate hosted control plane. That is a strong match for organisations that need evaluation and usage data to remain in their environment, but it also makes operational responsibility their own.

OpenFeature compatibility gives the system a standards-based foundation, and its purpose is to separate feature releases from application deployments. The free service comes with community support; teams that need a formal support relationship must move to enterprise.

Key features

Targeting rules cover individual users and segments, while percentage and progressive rollouts support gradual exposure. Scheduled changes are useful for timed launches, and A/B testing adds an experimentation path alongside ordinary release management. Together, these controls suit teams that need staged delivery rather than simple on-or-off switches.

Client and server SDKs span 16 languages and frameworks, including JavaScript, TypeScript, React, Angular, Swift, Kotlin/Android, Go, Java, .NET, Python, Node.js, PHP, Ruby, Rust, and NestJS. That breadth reduces the need to build separate flag plumbing for mixed technology estates, although the self-hosted service still needs to be maintained by the customer.

Built-in retrievers can read configuration from HTTP(S), local files, Kubernetes ConfigMaps, cloud storage, Git providers, MongoDB, Redis, and PostgreSQL. Exporters send evaluation data to Kafka, AWS S3, Google Cloud BigQuery, OpenTelemetry, webhooks, or application logs, allowing teams to connect flag activity to existing data and observability systems. Notifications can reach Slack, Discord, Microsoft Teams, webhooks, or logs when configuration changes. Go interfaces allow custom retrievers, exporters, and notifiers, which is valuable when standard connectors do not match an internal platform.

Pricing

Opensource

The Opensource plan costs nothing, billed forever. It includes all features, runs on your own infrastructure, allows unlimited feature flags, and provides community support only. There are no per-seat or flag-count charges stated, making it a practical default for teams comfortable operating the relay and handling their own support.

Enterprise

Enterprise uses custom pricing. It adds premium support, an SLA on CVE fixes, direct maintainer communication, integration help, roadmap previews, and team training. Choose it when response commitments, guided integration, or a formal security-fix obligation matter more than keeping the service entirely self-supported.

Platforms

GO Feature Flag supports Android, iOS, Linux, macOS, Windows, web, API, and self-hosted deployments. The SDK coverage makes it suitable for organisations delivering across mobile, desktop, web, and server environments.

Who it's for

This is a strong fit for engineering teams that require self-hosting, OpenFeature compatibility, extensive rollout controls, and strict control over evaluation data. It is less suitable for organisations that want a fully managed service or included vendor-backed support without purchasing enterprise coverage.

Pros and cons

• Pros: The MIT license permits commercial use; unlimited flags and all features are included in the free plan; rollout, scheduling, segmentation, and A/B testing cover sophisticated release workflows; SDKs and integrations span diverse stacks and infrastructure; self-hosting keeps evaluation and usage data in the customer environment.
• Cons: The free plan offers community support only; operating the relay, configuration sources, and integrations remains the customer's responsibility; premium support and an SLA on CVE fixes require custom-priced enterprise service.

Alternatives

Feature Flag Software is the broader category starting point for comparing other tools.

Flagsmith is worth choosing if you prefer a freemium product with a free trial and open-source core functionality under a BSD-3 licence.

Featurevisor is a straightforward alternative for MIT-licensed self-hosting with no per-seat pricing.

Unleash suits teams wanting an open-source plan with one project, two environments, and up to 5,000 feature flags per instance.

ConfigCat is a better fit for a managed free tier capped at 10 flags, two environments, two products, and 5 million config JSON downloads per month.

Featureflip is an option for teams comfortable with a small, explicitly capped free workspace.

Flipt is an alternative for Git-native workflows with UI synchronisation and unlimited flags on its open-source plan.

feat fits teams seeking hosted limits such as 7,500 monthly active users, 100 server connections, and two projects on its free tier.

Featureflow is suited to small teams wanting a free hosted plan with up to five seats, one project, two environments, and 1 million SDK requests per month.

Verdict

Choose GO Feature Flag if you need an MIT-licensed, self-hosted OpenFeature system with unlimited flags, deep rollout controls, and extensive integration options. Look elsewhere if your priority is a managed service or guaranteed vendor support and CVE response without moving to custom-priced enterprise.