Official API or Relay? One Decision Table (2026)
Not every case suits a relay, nor every case the official API. A five-dimension decision table — plus an honest account of where relays fall short.
Locate your real obstacle first
People agonize over 'should I use a relay' when the real question is 'where am I stuck'. Stuck on payment → relay, or issue your own card; stuck on network → relay; stuck on cost → model tiering (cheap tiers for simple tasks) beats switching vendors; stuck on features → official only. State the obstacle clearly and the answer is usually self-evident.
Relay capability boundaries: three things to ask
① Which of the model's capabilities are supported (file input, tool calling, streaming, tiered pricing for long context); ② whether failed calls are billed and whether the listed price equals the actual charge; ③ who you can reach when something breaks. An honest provider tells you what it does not support — one that says 'not supported' is more credible than one claiming everything. Our own boundaries are documented: no PDF/document input, cache hits not assured, no vendor-level contract SLA.
Running both is common
Many teams configure one route as primary and the other as backup. The reason is practical — any single channel can wobble (official APIs have outages and rate limits too). Both channels use the same OpenAI-compatible code; switching is a base_url change, nearly free, yet it preserves business continuity during a failure.
A common cost misconception
'Relays are always cheaper' is false. A relay's price depends on its procurement discount; some sit below list, some above (especially small platforms without buying power). The only test: convert the quote to USD per million tokens and compare with the vendor's current list price. Also beware quotes persistently below the vendor's cost — that is not sustainable.
Five-dimension decision table
| Dimension | Official direct | Relay / aggregator | Who fits |
|---|---|---|---|
| Feature completeness | Everything, updated first | Common features; new ones lag | Need beta features → official |
| Payment convenience | International credit card required | Local payment methods | No international card → relay |
| Network reachability | Depends on region | Usually solved | Unstable direct access → relay |
| Multi-model comparison | Separate account per vendor | One key, switch freely | Need evaluations → relay |
| Account control | Fully yours | Depends on the provider | Long-term core workload → official |