Apache Superset vs Freelancer

Apache Superset is an open-source data-exploration and business-intelligence platform for building interactive dashboards and running ad-hoc SQL over dozens of database engines. Its REST API, documented at superset.apache.org/docs/api (confirmed live, redirecting to a 200 Swagger reference), exposes charts, dashboards, datasets, and database connections under `/api/v1/`, authenticated with a JWT access token obtained by POSTing credentials to `/api/v1/security/login` rather than a long-lived static key. Superset is self-hosted with no single Apache-run public instance, so HTTPS and CORS are configured per deployment rather than fixed by a vendor.

Freelancer's API mirrors the full marketplace — projects, bids, milestones, messages, and user profiles — behind a standard OAuth 2.0 app-registration flow: a live call to `/api/users/0.1/self/` returns 401 `NOT_AUTHENTICATED` rather than any keyless access, and the OPTIONS preflight explicitly whitelists a custom `Freelancer-OAuth-V1` header, reconfirming OAuth as the real mechanism. A GET against the public `/api/projects/0.1/projects/active/` endpoint succeeds with no key at all and echoes `access-control-allow-origin: *` on both the GET and its preflight, resolving the stored 'unknown' CORS value to fully open. Freelancer's own Python SDK and developer portal document no separate paid tier or metering for the API itself — registering an app is free, with the marketplace's usual project fees applying only to actual freelance transactions, not API calls.