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Anthropic · Claude · Flagship

Claude Opus 5.5 (free lane)

New

Claude Opus 5.5 on the free lane for the hardest coding and reasoning work.

Model id

claude-opus-5-5:free

Price per 1M tokens

Input
$2.80
Output
$14.00
Cached input
Not offered

Added here 11 Nov 2026 — read the changelog for what changed and why.

Output is 5× the input rate. $1 covers about 102 prompts of 1,000 input + 500 output tokens. 1 credit = $1 of usage. All rates

Start using Claude Opus 5.5 (free lane)

Set ONEAIAPIKEY_API_KEY to a key from your console, then run any example. Streaming is on so long answers are not cut off by idle-connection timeouts.

curl https://api.oneaiapikey.com/v1/chat/completions \
  -H "Authorization: Bearer $ONEAIAPIKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-opus-5-5:free",
    "stream": true,
    "messages": [{"role": "user", "content": "Add rate limiting to the login route, update the tests and run them."}]
  }'
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.oneaiapikey.com/v1",
    api_key=os.environ["ONEAIAPIKEY_API_KEY"],
)

stream = client.chat.completions.create(
    model="claude-opus-5-5:free",
    messages=[{"role": "user", "content": "Add rate limiting to the login route, update the tests and run them."}],
    stream=True,  # recommended for long outputs
)
for chunk in stream:
    if chunk.choices and chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.oneaiapikey.com/v1",
  apiKey: process.env.ONEAIAPIKEY_API_KEY,
});

const stream = await client.chat.completions.create({
  model: "claude-opus-5-5:free",
  messages: [{ role: "user", content: "Add rate limiting to the login route, update the tests and run them." }],
  stream: true,
});

for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? "");
}

More: quickstart · API reference · try it in Chat first

Tokens per day, by model

Last 7 days, UTC days

Hover, tap or drag across any day, or focus the chart and use the arrow keys, to see how every model did that day.

Real tokens served through this gateway, updated every 5 minutes. Ranked by usage, not quality.

Full ranking insights

Claude line-up

Claude Opus 5.5 (free lane) or Claude Fable 5.1 or Claude Opus 5.5?

Of the 9 Claude models on this site, Claude Fable 5.1 is the step up from Claude Opus 5.5 (free lane) and Claude Opus 5.5 the step down. Each comparison lists the published rates and limits, then what favours each side.

Claude Opus 5.5 (free lane)vsClaude Fable 5.1

Per 1M tokensClaude Opus 5.5 (free lane)Claude Fable 5.1
Input$2.8060% less$7
Output$1460% less$35
Context1Mthe same1M
Max output128kthe same128k

Pick Claude Opus 5.5 (free lane) when

  • cost per request decides it: Claude Opus 5.5 (free lane) charges input 60% less and output 60% less than Claude Fable 5.1.
  • the work is agentic coding, large refactors and complex reasoning, which this catalogue lists for Claude Opus 5.5 (free lane) and not for Claude Fable 5.1.

Pick Claude Fable 5.1 instead when

  • Claude Opus 5.5 (free lane) does not list Prompt caching and your code depends on it.
  • your workload looks like long agent runs, front-end code and analysis, labels the catalogue gives Claude Fable 5.1 only.

Claude Opus 5.5 (free lane)vsClaude Opus 5.5

Per 1M tokensClaude Opus 5.5 (free lane)Claude Opus 5.5
Input$2.80the same$2.80
Output$14the same$14
Context1Mthe same1M
Max output128kthe same128k

Pick Claude Opus 5.5 (free lane) when

Nothing in the published data puts it ahead of Claude Opus 5.5.

Pick Claude Opus 5.5 instead when

  • Claude Opus 5.5 (free lane) does not list Prompt caching and your code depends on it.
  • the client speaks the Anthropic Messages format, as Claude Code does.

Use cases

What Claude Opus 5.5 (free lane) is listed for, and what it costs

The catalogue lists Claude Opus 5.5 (free lane) for agentic coding, large refactors and complex reasoning. Each row prices one typical request at the published rates, with the arithmetic shown. Token counts are examples; your prompts will differ.

Model your own traffic

  1. Agentic coding

    One turn of a long agent session: 60,000 tokens of context, and 3,000 tokens of edits and tool calls back.

    Give it a clear goal and let it plan, edit and run tests across many turns.

    “Add rate limiting to the login route, update the tests and run them.”

    Same request on Claude Fable 5.1 $0.1875 and Claude Opus 5.5 $0.08. Cheapest flagship-tier model in the family: Claude Opus 5.5 at $0.08, 62% less.

    $0.21

    per agent turn, about 47 per $10

    0.06 × $2.80 + 0.003 × $14

  2. Large refactors

    A refactor planned in one pass: 150,000 tokens of source in, a plan and patch of 8,000 tokens out.

    Share the relevant files up front so the whole change is planned in one pass.

    “Split payments.ts into a provider interface and one file per provider without changing behaviour.”

    Same request on Claude Fable 5.1 $1.33 and Claude Opus 5.5 $0.532. No other flagship-tier Claude model on this site does this job for less.

    $0.532

    per refactor pass, about 18 per $10

    0.15 × $2.80 + 0.008 × $14

  3. Complex reasoning

    A hard question with its supporting material: 8,000 tokens in, 4,000 tokens out including the reasoning.

    Ask for a short plan before the answer when the problem has several moving parts.

    “Given these three incident timelines, find the shared root cause and the evidence for it.”

    Same request on Claude Fable 5.1 $0.196 and Claude Opus 5.5 $0.0784. No other flagship-tier Claude model on this site does this job for less.

    $0.0784

    per answer, about 127 per $10

    0.008 × $2.80 + 0.004 × $14

Overview

When Claude Opus 5.5 (free lane) fits

Claude Opus 5.5 (free lane) is a flagship model from Anthropic, available here under the exact model id “claude-opus-5-5:free”. In the Claude line-up here it sits between Claude Fable 5.1 and Claude Opus 5.5. Anthropic has not published a release date we can cite; it has been available here since 11 Nov 2026.

Anthropic documents tools, vision, reasoning and structured output for it, and it reads images as well as text.

It costs $2.80 per million input tokens and $14 per million output tokens, so output is 5× the input rate. On the use cases below, output makes up 20% of the bill for agentic coding, 21% for large refactors and 71% for complex reasoning, so trimming the context you send saves more than capping the answer. With a 3:1 input-to-output mix it ranks 24th lowest-cost of the 27 models on this site.

There is no discounted cached-input rate for this model, so every input token bills at $2.80 per million.

It is served through the OpenAI-compatible format at https://api.oneaiapikey.com/v1, so any SDK or tool that lets you set a custom base URL, for example Codex CLI, Cursor and Cline, can use it. It is not offered on the Anthropic Messages endpoint; pick an Anthropic-format model for Claude Code.

Use Claude Opus 5.5 (free lane) with any balance.

Claude Opus 5.5 (free lane) is a paid model: any balance above $0 pays for it, the $10.00 sign-up credit included. When it runs out, add $1 or more to your wallet. Every request is billed at the rates above, with a receipt in your usage log.

Claude Opus 5.5 (free lane) is developed by Anthropic. Model names and trademarks belong to their owners. One AI API Key is an independent API gateway and is not affiliated with, endorsed by or sponsored by Anthropic.