3scale.net offers API management as a SaaS freemium model. The benefit is that it allows a simple mechanism to secure APIs.
- Access control
- Definition of usage policies (eg, rate limits)
- API traffic analytics
- Developer portals
- Interactive API documentation (Swagger-based)
- API monetization
A very common deployment model is using nginx as an API gateway.
3scale seems commercial only at this point, and we have a primarily open source focus. It doesn't seem a good match at the moment.