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Claude Opus 5.5 API: Endpoint & 30% Discount

Up to 30%

Claude Opus 5.5 is a multimodal chat model that accepts text and images and replies in text.

Compare Claude Opus 5.5 alternatives (31) →

What is Claude Opus 5.5?

Claude Opus 5.5 is a multimodal chat model that accepts text and images and replies in text, built by Anthropic and served on LLM API under the id claude-opus-5-5. It is reachable over the same OpenAI-compatible endpoint as every other model in the catalogue, so switching to it is a one-line change. The prices, context window and provider routing below come straight from the live catalogue and are refreshed every week.

Can you self-host Claude Opus 5.5?

No. We found no public weights for Claude Opus 5.5 on Hugging Face, so there is nothing to download, quantize or serve on your own GPUs: no VRAM budget, no vLLM or GGUF build to plan for. The only way to run it is over an API.

Skip the deploy — use LLM.API as your endpoint

No GPUs, no quantization trade-offs. Same model, OpenAI-compatible, up to 30% below list price.

Providers

LLM.API routes Claude Opus 5.5 to the providers below, with discounted effective rates versus list price.

List price by provider ($ / 1M tokens)

InputOutput
anthropic$5 in
$25 out
aws-bedrock$5 in
$25 out
aws-mantle$5 in
$25 out

Provider list prices; the LLM.API discount applies on top.

ProviderPricingContextCapabilities
anthropic30% offin $4000; out — per 1M tokens1M tokensvision, tools, streaming, reasoning, web search, JSON, structured

Prices and availability from the LLMAPI catalogue, updated nightly. Last updated 24 Sept 2026.

Try this model

Test Claude Opus 5.5 right here — free to start.

Claude Opus 5.5
Hi! Want to test the model?

Suggestions for your first prompt

Code snippet

Call Claude Opus 5.5 through the OpenAI-compatible API — POST /v1/chat/completions.

Switching from OpenAI? Change 2 lines.

- base_url="https://api.openai.com/v1"
- api_key="YOUR_OPENAI_KEY"
+ base_url="https://api.llmapi.ai/v1"
+ api_key="YOUR_LLMAPI_KEY"

Everything else stays the same — SDK, message format, tools, streaming. Set model to claude-opus-5-5 and the call runs unchanged.

bash
curl https://api.llmapi.ai/v1/chat/completions \
  -H "Authorization: Bearer $LLMAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-opus-5-5",
    "messages": [
      {"role": "user", "content": "Give me three crisp launch checklist items."}
    ],
  "reasoning_effort": "low"
  }'
from openai import OpenAI

client = OpenAI(
    api_key="YOUR_LLMAPI_KEY",
    base_url="https://api.llmapi.ai/v1",
)

resp = client.chat.completions.create(
    model="claude-opus-5-5",
    messages=[
        {"role": "system", "content": "You are a precise product assistant."},
        {"role": "user", "content": "Give me three crisp launch checklist items."},
    ],
    reasoning_effort="low",
)
print(resp.choices[0].message.content)
import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.LLMAPI_KEY,
  baseURL: "https://api.llmapi.ai/v1",
});

const resp = await client.chat.completions.create({
  model: "claude-opus-5-5",
  messages: [
    { role: "user", content: "Give me three crisp launch checklist items." },
  ],
});

console.log(resp.choices[0].message.content);
stream = client.chat.completions.create(
    model="claude-opus-5-5",
    messages=[{"role": "user", "content": "Write a haiku about latency."}],
    stream=True,
)

for chunk in stream:
    delta = chunk.choices[0].delta.content
    if delta:
        print(delta, end="", flush=True)
{
  "model": "claude-opus-5-5",
  "messages": [
    {"role": "system", "content": "You are a precise product assistant."},
    {"role": "user", "content": "Give me three crisp launch checklist items."}
  ],
  "reasoning_effort": "low"
}

Supported endpoints & features

Base URL https://api.llmapi.ai/v1 · model ID claude-opus-5-5 · OpenAI-compatible.

  • POST /v1/chat/completionsChat Completions — supported
FeatureStatusHow to set it
Function calling (tools)Supportedtools, tool_choice
Parallel tool callsNot supportedparallel_tool_calls
JSON modeSupportedresponse_format: {"type": "json_object"}
Structured outputsSupportedresponse_format: {"type": "json_schema", …}
StreamingSupportedstream: true
Vision (image input)Supportedimage_url content parts
Web searchSupportedweb_search
Reasoning effortlow · medium · high · xhigh · maxreasoning_effort: "low"

Errors & fallback routing

CodeWhat it meansWhat to do
401Missing or invalid API key.Send Authorization: Bearer YOUR_LLMAPI_KEY and check the key is active.
429Rate limited, or the upstream provider is throttling the request.Back off and retry with jitter; the gateway also retries the request on another provider where one is available.
5xxUpstream provider error or timeout.Retry; fallback routing sends the retry to the next healthy provider for this model.

When a provider fails or throttles, the request is routed to the next provider serving this model — the ones listed in the providers table above.

Why run Claude Opus 5.5 on LLM.API?

  • Unified AI Routing

    Reach Claude Opus 5.5 and sibling models through one OpenAI-compatible endpoint.

  • Cost Control

    Production: Compare provider price points and keep spend visible as you scale Claude Opus 5.5.

  • Reliability Layer

    Retry and route across configured providers when a single upstream blips.

  • Observability

    Trace prompts, tokens, and errors for Claude Opus 5.5 alongside the rest of your stack.

  • Drop-in SDKs

    Keep using familiar OpenAI client patterns with base URL https://api.llmapi.ai/v1.

  • Model Breadth

    Swap Claude Opus 5.5 for chat, media, or embedding alternatives without rewriting auth.

When to Use — When NOT to Use

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