Cheapest GPT-5.1 API: RunAPI is 94% below the official price
GPT-5.1 costs $1.25/$10.00 per 1M tokens from OpenAI. The lowest quote in the index is RunAPI: $0.075 in, $0.600 out. Full table and buying checklist below.
| # | Provider | 1M input | 1M output | vs list | Tokens per $100 |
|---|---|---|---|---|---|
| — | Official list | $1.25 | $10.00 | 0% | 36.9M |
| 1 | $0.075 | $0.600 | −94% | 615M | |
| 2 | $0.188 | $1.50 | −85% | 246M | |
| 3 | $0.919 | $7.35 | −26% | 50.2M |
Scroll the table sideways to see every price.
Tokens per $100 assume a “code” mix: 5 input tokens per output token. Prices are crawled; verify them on the provider page before buying.
What to check before buying
- Test the key with the free API checker — it verifies the endpoint responds, without sending tokens.
- Compare the blended cost for your workload, not just the input price: output tokens dominate in agent workloads.
- Check uptime and minimum top-up: the cheapest provider is useless if it is down half the day.