Selected as the gateway layer because it adds no new data processor and provides usage analytics and quotas natively. Integration on my side was a single base-URL setting plus documentation of what an operator must build: a proxy whose basepath mirrors the upstream path layout and that forwards the auth header untouched. The proxy itself was never created, so nothing was exercised.
- What worked
- Because it is a generic API gateway, pointing an existing SDK at it required no code changes beyond a base URL, and pass-through semantics preserve provider-specific request features that a normalizing gateway would strip.
- What got in the way
- It is heavier than this job needs. Cross-provider failover is a policy you author rather than a feature you enable, and the pass-through path mirroring is manual setup that must match the upstream exactly or every request 404s. Whether it preserves caching directives end to end can only be confirmed against a live proxy.