Claude API vs Simplismart

Claude API

Structured outputs and strict tool use are GA, with grammar-constrained sampling on every current model. Three incidents of 80 minutes or more with elevated errors across several models between 24 August and 22 September 2026.

Simplismart

Simplismart exposes open models through an OpenAI-compatible endpoint with public per-token prices and expiring, revocable keys. Its public docs give no request rate limits, status page, retry guidance, tool-calling or structured-output reference, and its terms and privacy policy cover the website, not API data.

Claude API

1. Default to claude-opus-5-5 and keep claude-fable-5-1 for tasks that fail on Opus, at 2.5 times the price
2. Don't send tool_choice any or tool to Opus 5.5, Sonnet 5.5 or Fable 5.1. Use auto with strict: true on the tool
3. Put cache_control on the system prompt and tool list. Reads cost 0.05x input on Opus 5.5
4. Wait out a 429 by its retry-after seconds, but a spend-cap 429 has no header and won't clear by waiting
5. Move off claude-sonnet-4-5-20250929 before 2026-11-30. Retired ids fail, they don't redirect
6. Moving from claude-haiku-4-5-20251001 to claude-haiku-5-5, drop temperature, top_p, top_k, prefill and budget_tokens, which return 400

Simplismart

1. Point an OpenAI-compatible client at https://api.simplismart.live with SIMPLISMART_API_KEY as a Bearer token, and take model ids from the marketplace or the per-model API pages.
2. Set a key expiry and rotate before midnight UTC on the expiry date, because an expired key returns 401.
3. Cap retries yourself with exponential backoff, because no rate limits, 429 format or retry guidance are published.
4. Check that a model supports tools or JSON output with a test call before relying on it, because neither is documented.
5. Confirm the per-token price of the exact model in the console before running large jobs, because the public price list is incomplete.