tyk

Tyk is an API gateway that sits in front of your services and handles authentication, rate limiting, analytics, and versioning. Consider it a bouncer for your API: checks credentials, enforces quotas, logs everything.

Go-based. Tyk's open source gateway handles the core job: proxying requests, applying rate limits, key authentication, and basic analytics. It's Docker-friendly and runs as a single binary.

The open source gateway is free under a modified license (check the terms; it's not a standard permissive license). The paid tiers add a management dashboard, developer portal, multi-data-center support, and enterprise SSO. Tyk Cloud starts around $500/mo. Self-hosted pro licenses are custom-quoted. Solo or small teams: the free gateway handles basic API management fine. You configure it via API calls or config files, no GUI. Medium teams: you'll probably want the dashboard once you're managing 10+ APIs. Large orgs: the enterprise features (RBAC, federation, portal) justify the cost.

The catch: the free tier is deliberately limited to push you toward paid. No dashboard, no developer portal, no visual API designer. The licensing is also murky, not Apache or MIT, so check compliance before deploying commercially. Kong is the more common open source choice with a clearer license story.