Anthropic: Claude Opus Latest (Claude Opus 5.5)
Claude Opus Latest (Claude Opus 5.5) is a reasoning model from Anthropic released on Mar 29, 2026. It reads text, images and files and writes text, with a 1M token context window and up to 128K tokens per reply.
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It costs $4 per million input tokens and $20 per million output tokens. Cached input bills at $0.20, 95% less than fresh input.
It supports tool calling, structured JSON output and prompt caching.
3 providers serve it, including Eden AI, NanoGPT and The Grid AI.
- Modalities
- In / out price
- $4 / $20 per 1M
- Context
- 1M
- Max output
- 128K
- Released
- Mar 29, 2026
- Knowledge cutoff
- Jun 2026
- Tool calling
- Structured output
- Reasoning
- Prompt caching
- Open weights
- Free to use
Claude Opus Latest (Claude Opus 5.5) pricing
USD, as listed on Oct 15, 2026. Most bills are input heavy, so the cached input rate matters as much as the headline price.
| Input | $4 / 1M tokens | |
|---|---|---|
| Output | $20 / 1M tokens | |
| Cached input (read) | $0.20 / 1M tokens | 95% off input |
| Cache write | $5 / 1M tokens |
Claude Opus Latest (Claude Opus 5.5) providers
3 providers serve it, including Eden AI, NanoGPT and The Grid AI. Each host sets its own price and limits, so the cheapest one is not always the one with the longest context.
| Provider | Input /M | Output /M | Cache read /M | Context | Max output |
|---|---|---|---|---|---|
| Eden AI | $4 | $20 | $0.20 | 1M | 128K |
| NanoGPT | $4 | $20 | $0.20 | 1M | 128K |
| The Grid AI | n/a | n/a | – | 1M | 128K |
What Claude Opus Latest (Claude Opus 5.5) costs per month
Pick a workload close to yours or type your own volumes.
Supported request parameters
What you can set when you call Claude Opus Latest (Claude Opus 5.5) through an OpenAI compatible API.
- Tools
tools - Structured outputs
structured_outputs - Reasoning
reasoning
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Claude Opus Latest (Claude Opus 5.5) questions
How much does the Claude Opus Latest (Claude Opus 5.5) API cost?
$4 per million input tokens and $20 per million output tokens, with cached input at $0.20. The estimator on this page turns that into a monthly bill for your own workload.
What is the context window of Claude Opus Latest (Claude Opus 5.5)?
1,000,000 tokens of input, and it can write up to 128,000 tokens in one reply. As a rough guide, a million tokens is around 750,000 English words.
Which providers serve Claude Opus Latest (Claude Opus 5.5)?
3 providers serve it, including Eden AI, NanoGPT and The Grid AI. Prices differ by host, so the Providers table on this page lists each one with its input and output price.
Does Claude Opus Latest (Claude Opus 5.5) support tool calling?
Yes. It accepts tool definitions and can return JSON that matches a schema, which is what an agent needs to call your APIs.
Is Claude Opus Latest (Claude Opus 5.5) open source?
No. Anthropic serves it through an API only, so you cannot download the weights or host it yourself.
When was Claude Opus Latest (Claude Opus 5.5) released?
Mar 29, 2026, with training data up to Jun 2026.
Catalog data from models.dev (MIT licensed), refreshed daily, last on Oct 15, 2026. The summary is written from these facts.
Building on Claude Opus Latest (Claude Opus 5.5)?
I test your real tasks on it and the two closest alternatives, then ship the agent on whichever wins on cost and accuracy.
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