Claude Opus 5.5
Save 72%Officialanthropic/claude-opus-5-5
Anthropic's new flagship — successor to Opus 5, priced 20% lower with cache reads at 5%.
- Context window
- 1M
- Max output
- 8K
- Input modalities
- text · image
- Output modalities
- text
- Capabilities
- Vision · Reasoning · Tool calling · Coding · Prompt cache · Paid cache writes · Strip Sampling Params
- Upstream release
- 2026-09-22
- RouteMux name
- anthropic/claude-opus-5-5
Try Claude Opus 5.5 here
Tune the request, see the current price ceiling, and inspect the real response without leaving this model page.
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Enter an input on the left. The same RouteMux Playground execution and billing path powers this embedded test.
What is Claude Opus 5.5
Claude Opus 5.5 is Anthropic's new recommended flagship, replacing Claude Opus 5 as the model Anthropic suggests starting with for most workloads. It is built for long-running agentic coding and knowledge work: multi-file refactors, extended tool-use loops, and analysis that needs a large codebase or document set in view at once. It takes a 1M-token context window and vision input, with adaptive thinking always on and a default reasoning effort of "medium."
Through RouteMux it costs $1.12 per 1M input tokens against Anthropic's $4, and $5.60 per 1M output against $20 — the same model and the same Anthropic Messages API, routed through one key alongside every other model in the catalog. Failed and timed-out requests are not billed. Prompt caching is priced separately: reads are $0.056 per 1M tokens and writes are $1.40 (5-minute) or $2.24 (1-hour) per 1M tokens. Notably, cache reads on Opus 5.5 are billed at 5% of the base input rate, where most Claude models use 10% — caching pays off faster here than on Opus 5 or Sonnet 5.
Claude Opus 5.5 API pricing
Source: anthropic_x0.28 · Verified 2026-09-23
Cache read $0.056/M · Cache write $1.4/M
Estimate cost
Limited time20% extra Credits on your first top-up — up to 200 bonus Credits
Applies to your first top-up within 72 hours of signing up. Minimum $20, once per account.
Key capabilities
1M-token context
Enough to hold a mid-sized repository or a full document set in a single request, so long-horizon tasks do not need retrieval plumbing to get started.
Cheaper than Opus 5
Input and output pricing is 20% below Claude Opus 5, while Anthropic reports comparable quality at default settings on typical agentic workloads.
Cache reads at 5%
Cache reads cost $0.056 / 1M against a $1.12 base rate — half the 10% ratio most Claude models use for cache reads.
Vision input and tool calling
Accepts images alongside text, and supports native function calling for agentic loops — screenshots, diagrams, and tool results all go in the same conversation.
Interface and protocols
Use any of these IDs to call this model via the API.
anthropic/claude-opus-5-5Replace the ROUTEMUX_KEY placeholder with your API key. Create one →
from anthropic import Anthropic
client = Anthropic(
base_url="https://api.routemux.com/anthropic",
api_key="<ROUTEMUX_KEY>",
)
message = client.messages.create(
model="anthropic/claude-opus-5-5",
max_tokens=1024,
messages=[{"role": "user", "content": "What is the meaning of life?"}],
)
print(message.content[0].text)Performance (last 30 days)
Claude Opus 5.5 FAQ
›What is Claude Opus 5.5?
Anthropic's new flagship — successor to Opus 5, priced 20% lower with cache reads at 5%.
›How large is the context window of Claude Opus 5.5?
Claude Opus 5.5 supports a context window of up to 1M tokens, with up to 8K output tokens per request.
›How much does the Claude Opus 5.5 API cost?
Through RouteMux, Claude Opus 5.5 costs $1.12 for input and $5.6 for output (USD per 1M tokens), below the official list price.
›How do I call Claude Opus 5.5 via API?
Claude Opus 5.5 is OpenAI-compatible: point your base URL at RouteMux and set the model field to anthropic/claude-opus-5-5 — no code changes needed.
›Which input and output modalities does Claude Opus 5.5 support?
Claude Opus 5.5 accepts text, image as input and produces text as output.
›When was Claude Opus 5.5 released?
Claude Opus 5.5 was released on September 22, 2026.
›Is this the same Claude Opus 5.5 as Anthropic's?
Yes — same model, same Anthropic Messages API surface. RouteMux routes your request through and bills your prepaid wallet instead of an Anthropic account.
›Should I use Opus 5.5 or Opus 5?
Opus 5.5 is Anthropic's current recommendation for most workloads and costs less per token. Opus 5 remains available if you need to keep an existing integration pinned.
Sources
Reviewed by Jerry Fan on 2026-09-23