Anthropic API vs OpenAI API
Compare Anthropic API and OpenAI API on pricing, free tier, open source, API, self-host, verdict and momentum.
Both are models-api tools. Anthropic API is paid (pay-as-you-go, from $1/1M input (Haiku 4.5); small free credits for new users) with an API; OpenAI API is paid (pay-as-you-go and from $0.20/1M input (GPT-5.6 Luna); GPT-5.6 Sol promotional $4/$20 at least through 2026-11-21 (list $5/$30); no free tier) with an API. The catalog stamp is ship for Anthropic API and ship for OpenAI API, last verified 2026-08-19 and 2026-08-19 respectively.
Auto-paired from catalog data — the verdicts are hand-set, the pairing is algorithmic.
Anthropic API
Claude models direct — the practitioner's pick for coding and long-form text.
OpenAI API
GPT-5 family and o-series reasoning models behind one API.
| field | Anthropic API | OpenAI API |
|---|---|---|
| pricing | paid · pay-as-you-go, from $1/1M input (Haiku 4.5); small free credits for new users | paid · pay-as-you-go, from $0.20/1M input (GPT-5.6 Luna); GPT-5.6 Sol promotional $4/$20 at least through 2026-11-21 (list $5/$30); no free tier |
| free tier | no | no |
| open source | no | no |
| api | yes | yes |
| self-host | no | no |
| verdict | ship | ship |
| momentum | blueshift | steady |
| last verified | 2026-08-19 | 2026-08-19 |
| key limitation | Capacity crunches at peak demand have caused 429s. | Premium pricing at the frontier tier. |
The call
Pick Anthropic API for production Claude calls when you need the lab API, not the…
Pick OpenAI API for shipping an app on the GPT-5 family without assembling a ro…
Anthropic API sources
OpenAI API sources
Open live compare →Anthropic API pageOpenAI API pageAnthropic API.jsonOpenAI API.json