Search results for "Claude Opus 5.5 free" are full of sites promising unlimited access with no sign-up. Those are not Anthropic, and there is no way for a third party to give away a model that costs $20 per million output tokens indefinitely without either limiting you, logging your data or serving something else. Here is what is actually available and what it costs.
Subscription prices change often; check claude.com/pricing for the current figures. The API prices below are Anthropic’s list and ours as of 30 September 2026.
| Route | Opus 5.5 included? | Cost |
|---|---|---|
| claude.ai Free | No (Sonnet / Haiku tier only) | $0 |
| claude.ai Pro / Max / Team | Yes, with usage limits | monthly subscription |
| Anthropic API | Yes | $4 / $20 per 1M tokens |
| New-account or cloud credits | Yes, until the credit runs out | free, finite |
| apimodels.app API | Yes (claude-opus-5-5) | $2.40 / $12 per 1M tokens, no subscription |
A subscription makes sense if you chat with Claude every day. If you need Opus 5.5 for a few coding sessions or API jobs a week, per-token billing costs less: a coding turn that sends 50,000 input tokens, mostly cached, and returns 3,000 tokens costs a few cents on apimodels.app. You can also use it in Claude Code by pointing ANTHROPIC_BASE_URL at https://api.apimodels.app.
If Opus 5.5 is more than you need, Sonnet-tier models are on the free claude.ai plan and cost half as much on the API. See the Opus 5.5 vs Sonnet 5.5 comparison for where the smaller model is enough.
cURL
curl https://api.apimodels.app/v1/messages \
-H "x-api-key: $APIMODELS_API_KEY" \
-H "anthropic-version: 2023-06-01" \
-H "Content-Type: application/json" \
-d '{"model": "claude-opus-5-5", "max_tokens": 16000,
"messages": [{"role": "user", "content": "Summarise the risks in this pull request: ..."}]}'No. The free plan offers Sonnet- and Haiku-tier models. Opus 5.5 is included with Pro and higher plans, subject to usage limits.
Only finite credits: new-account credits on the Anthropic API or promotional credits on cloud platforms. After that it is paid per token, $4 / $20 per million at Anthropic or $2.40 / $12 on apimodels.app.
Treat them with caution. They are not run by Anthropic, you cannot verify which model answers, and anything you paste may be logged. Do not send code, keys or personal data to them.
For occasional use, pay-as-you-go API access: $2.40 / $12 per million tokens on apimodels.app, 40% below Anthropic’s list, no subscription and no charge for failed calls. For daily chat use, a claude.ai Pro subscription may work out cheaper.
