Anthropic
Claude Opus 4.7
From $2.00 per 1M tokens
Chat
Claude Opus 5 — 1M Context, Agentic Coding
Claude Opus 5 is Anthropic's model for complex agentic coding and enterprise work. Claude Opus 5 reads a 1M-token context window, writes up to 128k tokens back, and runs adaptive thinking on by default with an effort dial from low through max. On reAPI, Claude Opus 5 bills at less than half Anthropic's published per-token rate on both input and output.
Claude Opus 5model
claude-opus-5Claude Opus 5 playground
Chat models run on the api.reapi.ai gateway, which has its own console and its own key. Open the console to run Claude Opus 5 through the OpenAI-compatible Chat Completions surface.
What you can build with this model
Real-world workflows and production use cases you can build and ship with this model.
Long-horizon agentic coding that finishes the job
Anthropic positions Claude Opus 5 for complex agentic coding and enterprise work, and the shape of the model matches that: a 1M-token context window means a whole repository, its tests and its issue history fit in one request, and 128k output tokens is room for a multi-file change rather than a stub. Adaptive thinking is on by default, so Claude Opus 5 holds a plan together across tool calls instead of restarting its reasoning each turn. The practical advice from Anthropic's own migration guidance is to give Claude Opus 5 the complete task specification up front in a single well-specified turn and let it run, rather than revealing the task across many short interactive turns.
Read the API docs
Code review and debugging with the filter turned off
Claude Opus 5 finds real bugs at high precision and high recall, and it stays accurate at lower effort — which makes a cheap fast pass at review time plus a thorough pass later a practical pattern. One caveat worth designing around: Claude Opus 5 follows severity instructions literally. A review prompt that says only report high-severity issues will get exactly that, and your measured recall drops even though the underlying bug-finding improved. Ask Claude Opus 5 to report everything with a confidence level and a severity, then filter in a separate pass.
Whole-document enterprise work without a chunking layer
Text, images and PDF are all inputs to Claude Opus 5, and the million-token window is large enough that a contract set, a research bundle or a year of filings goes in whole. That removes the retrieval layer whose only job was working around a small context. Claude Opus 5 also generates and edits complex multi-sheet spreadsheets with real formulas and builds slide decks that follow design conventions, and it can be told to follow a specific template when one is required. Vision is strong enough on charts and dense documents that giving Claude Opus 5 tools to crop and re-examine its own output beats simply raising the thinking depth.
Pricing
Credit-based — 1 credit = $0.001 USD. Pay only for completed generations.
| Category | Unit | Price |
|---|---|---|
| Token pricing | ||
| Input | 1M tokens | $2.4 |
| Output | 1M tokens | $12 |
Why reAPI
Under half the published rate
Anthropic publishes a per-million-token rate for Claude Opus 5 input and output. On reAPI, Claude Opus 5 bills at less than half of both — no subscription underneath it, no minimum commitment, pay-as-you-go in USD against your gateway balance. The exact numbers are in the pricing table on this page.
OpenAI-compatible drop-in
Claude Opus 5 is served from a standard `/v1/chat/completions` endpoint. If your code already speaks that shape, adopting Claude Opus 5 is a base URL, a key and a model string — the same SDKs work once the base URL points at the gateway. No SDK swap, no bespoke client.
One key across Claude, GPT and Gemini
The same api.reapi.ai key that calls Claude Opus 5 calls the GPT and Gemini families too. Comparing Claude Opus 5 against another frontier model, or failing over when one provider has a bad hour, is a model string rather than a second integration, a second invoice and a second set of credentials.
Claude Opus 5 vs Claude Opus 4.8
This comparison is not about price. Anthropic publishes the same per-token rate, the same one-million-token context window and the same 128k output ceiling for both models. Claude Opus 5 is the capability step-change on top of that, and it quietly changes two request-surface defaults that will break code carried straight over — thinking now runs by default, and turning it off is capped at high effort.
Capability
Claude Opus 5 on reAPI
Claude Opus 4.8
Anthropic's positioning
For complex agentic coding and enterprise work; the current Opus generation
The most capable model of the Opus 4 series, now the previous generation
Published rate
Identical published per-token rate — and less than half of it on reAPI
Identical published per-token rate
Context and output limits
1M-token context, 128k max output
Identical — 1M-token context, 128k max output
Thinking default
On — omitting the thinking parameter runs adaptive thinking
Off — adaptive thinking has to be set explicitly
Disabling thinking
Accepted only at effort high or lower; rejected at xhigh and max
Accepted at any effort level
Prompt-cache minimum
512-token minimum cacheable prefix, so shorter prompts now cache
1024-token minimum — twice as long a prefix before caching starts
Comparison reflects behavior documented on Anthropic's own model-overview page at the time of writing. Rates are described as relationships rather than amounts; the live numbers for Claude Opus 5 are in the pricing table above.
Ship Claude Opus 5 in three steps
- step 01
Create an account and key on api.reapi.ai
Sign up at api.reapi.ai, open the console and generate an API key. That one key reaches Claude Opus 5 and every other model on the gateway, billed from a single balance.
Open - step 02
Point your client at the gateway
Set your base URL to api.reapi.ai and your key to the one you just created. Any client that already speaks OpenAI Chat Completions works unchanged — no SDK swap is needed to reach Claude Opus 5.
Open - step 03
Send `claude-opus-5` as the model
Set the model field to `claude-opus-5` and post your messages. Turn on streaming for long outputs, and remember that Claude Opus 5 thinks by default, so leave room in max tokens for the reasoning as well as the answer.
Open
Frequently asked questions
Common questions about this model.
Claude Opus 5 is billed pay-as-you-go in USD per token against your api.reapi.ai balance, with separate input and output rates and no subscription. Both rates sit at less than half Anthropic's published per-token rate. Current numbers are in the pricing table on this page.
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