Claude Opus 5.5 API — Access via an AI API Gateway
Call Anthropic’s Claude Opus 5.5 through byesu — an AI API gateway with pay-as-you-go billing and no subscription. It supports both the Anthropic-native and the OpenAI-compatible API, and plugs into Claude Code with two environment variables.
Model specs below are quoted from Anthropic’s official documentation, checked on 2026-10-16.
What It Is
Claude Opus 5.5 is Anthropic’s current flagship. Anthropic positions it for long-running agentic coding and knowledge work, and recommends it as the starting point for most workloads.
| Item | Value |
|---|---|
| Model ID on byesu | claude-opus-5-5 |
| Context window | 1M tokens |
| Max output | 128K tokens |
| Thinking | Adaptive thinking, default effort medium |
| Knowledge cutoff | June 2026 |
How Pricing Works
byesu bills per token with no monthly fee. The actual price of every model is shown live in the model list after you sign in, and the console records the charge for each request.
For reference, Anthropic’s official list price is $4 / $20 per million input / output tokens; cache reads are billed at 5% of the input price.
TIP
A token in the default auto group can call claude-opus-5-5 — no need to pick a group. A wrong group returns “no available channel”; see Choosing a Group.
How to Call It
The base URL depends on the API format:
- Anthropic native (
/v1/messages) →https://byesu.com - OpenAI-compatible (
/v1/chat/completions,/v1/responses) →https://byesu.com/v1
Authenticate with Authorization: Bearer sk-YOUR_TOKEN.
Option 1: Anthropic native /v1/messages
curl https://byesu.com/v1/messages \
-H "Authorization: Bearer sk-YOUR_TOKEN" \
-H "anthropic-version: 2023-06-01" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-opus-5-5",
"max_tokens": 1024,
"messages": [
{
"role": "user",
"content": "Explain what an API gateway is in one sentence"
}
]
}'Option 2: OpenAI-compatible /v1/chat/completions
from openai import OpenAI
client = OpenAI(api_key="sk-YOUR_TOKEN", base_url="https://byesu.com/v1")
resp = client.chat.completions.create(
model="claude-opus-5-5",
messages=[{"role": "user", "content": "Explain what an API gateway is in one sentence"}],
)
print(resp.choices[0].message.content)Use It in Claude Code
Point Claude Code at byesu with two environment variables:
export ANTHROPIC_BASE_URL="https://byesu.com"
export ANTHROPIC_API_KEY="sk-YOUR_TOKEN"
export ANTHROPIC_MODEL="claude-opus-5-5"Full steps and a one-line setup script: Claude Code CLI.
FAQ
How do I get Claude Opus 5.5 API access?
Sign up at byesu, create a token (the default auto group works), and call claude-opus-5-5 through the OpenAI-compatible endpoint https://byesu.com/v1, or the Anthropic-native /v1/messages at https://byesu.com. You can pay with USDT or Alipay.
How much does the Claude Opus 5.5 API cost on byesu?
byesu bills per token with no subscription; the live price is shown in the model list after you sign in. For reference, Anthropic’s official list price is $4 / $20 per million input / output tokens.
How long is the Claude Opus 5.5 context window?
According to Anthropic’s documentation, the context window is 1M tokens with up to 128K output tokens per request.
Can I call Claude Opus 5.5 with the OpenAI SDK?
Yes. Set the SDK base_url to https://byesu.com/v1, use your byesu token as the api_key, and set model to claude-opus-5-5.
What does “no available channel” mean when calling claude-opus-5-5?
Usually the token is in a group that does not include this model. Use the default auto group (or a group that lists the model) and check the model ID matches the console exactly.