How to Choose an AI API Relay: Price, Reliability and a Prepayment Test

You see an exceptionally low “from” rate in a relay directory. After opening the platform, you discover it belongs to a different model; the model you actually need has separate output, cache and minimum-charge rules. The useful question is not simply “which platform is cheapest?” It is which route completes my work at an acceptable, auditable cost?

This is a prepayment checklist, not an uptime ranking. Start with the relay directory, pick the exact target model, then apply four checks. Prices and routes change; verify the current checkout terms before paying. Checked September 24, 2026.

1. 01Same modelMatch model ID, version and billing units
2. 02Finished workRun your own coding, text or image task
3. 03Auditable billMatch requests, retries and charges
4. 04Safe exitCheck balance, refund, support and backup

A platform-wide lowest price finds candidates. It does not establish that a particular route is suitable for your workload.

1. Compare the same model and billing unit

A platform-wide minimum input rate may belong to a model you will never use. Match the model ID and version, then compare input, output, cache writes and reads, long-context tiers, request minimums and currency conversion. Image generation may be sold per image, size or quality tier; keep those native units instead of inventing a token conversion. Anthropic's pricing breakdown illustrates why an input-only comparison omits major charges.

Confirm the actual API features as well. “Compatible” does not establish that your client can use streaming, tool calls or image input. Treat an unspecified model or billing rule as unverified, not free.

2. Test your own workload

Short chat prompts are poor substitutes for coding agents, production concurrency or image generation. Shortlist two or three routes and run the same small, repeatable tasks with identical parameters and acceptance criteria. A small sample finds obvious incompatibilities, not long-term uptime.

For an agent-specific protocol test, use our fixed-provider versus auto-routing guide.

3. Calculate cost per accepted result

Divide the test batch's actual charges by accepted outputs, while retaining completion time and failure counts. As arithmetic only: a route costing CNY 10 for 10 accepted outputs costs CNY 1 each; CNY 14 for 18 costs about CNY 0.78 each. These are illustrative figures, not merchant measurements.

Reconcile every retry and uncertain timeout. Cloudflare's gateway logging guide shows the kind of per-request status, token, cost and duration records to look for; confirm what your chosen platform actually exposes. For images sold per call, use total paid divided by accepted images.

4. Check your exit before adding balance

Check transaction detail, minimum charges, unused-balance and refund terms, changes to model availability, and support evidence requirements. Domain verification does not certify upstream quality or future reliability. Our verification methodology separates those claims.

Add balance gradually only after a route passes your task and billing checks. An attractive quote with incomplete evidence remains a small-trial candidate; a route with unclear model identity or billing should not carry important traffic. Test a backup by the same standard.

Start from the provider directory, compare the exact model in model pricing, and let completed work and an auditable bill determine whether to prepay. For actual same-model rate examples, see our relay versus official price comparison.