Antseed vs StepFun API

Antseed

A buyer needs no account. The CLI creates a wallet key, free models answer at once and paid ones draw on deposited USDC, with seller, tokens and cost returned in response headers. Sellers are unvetted and can read prompts unless TEE-verified, the proxy forwards a client's own credential headers to them, and every package is pre-1.0.

StepFun API

StepFun's API serves Step 5 Preview with a 1M-token context, video input, strict JSON Schema output and published per-token prices, documented in Markdown with an llms.txt. The model is a preview with no release date found, there's no free allowance or SLA, and the terms and privacy policy leave room to train on customer data.

Antseed

1. Send a placeholder key such as antseed-p2p. The proxy forwards whatever Authorization or x-api-key header the client sends to the seller
2. Call GET /v1/models first and request a concrete id. The antseed alias works only when the desktop app has a model selected
3. Handle 402 insufficient_deposits by reading suggestedAmount, then fund the address from antseed buyer deposit with USDC on Base
4. Pass --verifiers antseed-verifier --require-verifier to antseed buyer start when prompts are private, so only TEE-verified sellers are routed
5. Read x-antseed-peer-id and x-antseed-estimated-cost-usd on each response, and pin a seller with <peerId>@<model> when the same one must answer

StepFun API

1. Set max_tokens yourself. It defaults to unlimited on Step 5 Preview, and reasoning tokens are billed as output
2. Use response_format with type: json_schema and strict: true when the shape matters. JSON Mode alone isn't schema-checked
3. Back off and retry on 429, 500, 503 and 504. The docs give no Retry-After header or backoff schedule
4. Expect HTTP 451 or finish_reason: content_filter when content fails StepFun's review, and don't retry the same input
5. Use api.stepfun.ai for the international platform. api.stepfun.com is the China platform with yuan pricing