---
title: "Claude Opus 5.5 — API access"
description: "Claude Opus 5.5 API pricing: official $4/$20 per 1M tokens, $2/$10 with the flat 50% apiToken.sale discount. Cache reads are $0.20 per 1M."
url: "https://apitoken.sale/models/claude-opus-5-5"
language: "en"
---
# Claude Opus 5.5

Claude Opus 5.5 is Anthropic's September 2026 Opus for long-running agentic coding, priced below Opus 5, with cache reads at 5% of input.

- **Model ID:** `claude-opus-5-5`
- **Tier:** Opus
- **Context window:** 1M tokens
- **Max output:** 128K tokens
- **Official price (per 1M):** $4 input / $20 output
- **Your price (per 1M):** input $2, output $10 (flat 50% off)
- **Base URL:** `https://router.apitoken.sale` · **Endpoint:** `POST /v1/messages`

## Best for

- Long-running agentic coding and large refactors.
- Knowledge work that previously needed Opus 5.
- Cache-heavy sessions: cache reads are $0.20 per 1M tokens.

## Notes

- Official rates per 1M tokens: $4 input, $0.20 cache read, $5 5-minute cache write, $8 1-hour cache write, $20 output.
- Fast mode bills $8 input, $0.40 cache read, $10 5-minute cache write, $16 1-hour cache write, and $40 output per 1M tokens.
- Adaptive thinking is always on. Thinking cannot be disabled, and forced tool_choice any/tool returns 400.

## Call it

```bash
curl https://router.apitoken.sale/v1/messages \
  -H "x-api-key: $APITOKEN_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{"model": "claude-opus-5-5", "max_tokens": 1024, "messages": [{"role": "user", "content": "Hello"}]}'
```

## FAQ

**How much does the Claude Opus 5.5 API cost?**

Officially $4 per 1M input tokens and $20 per 1M output tokens. Cache reads are $0.20, 5-minute cache writes $5, and 1-hour cache writes $8 per 1M. On apiToken.sale the flat 50% discount applies to every call: $2/$10.

**What is the model ID for Claude Opus 5.5?**

claude-opus-5-5. Use it unchanged with the Anthropic SDK, Claude Code, Cursor or any compatible tool pointed at https://router.apitoken.sale.

**Opus 5.5 or Opus 5?**

Opus 5.5 is the newer Opus and costs less: $4/$20 versus Opus 5's $5/$25, with cache reads at $0.20 instead of $0.50. New work should send claude-opus-5-5.

---
API reference: https://apitoken.sale/md/docs · All models: https://apitoken.sale/md/models