free-ai-api-keys

anthropic/claude-opus-5.5

Anthropic: Claude Opus 5.5

Context length
1000K
Input / 1M tokens
$4.00
Output / 1M tokens
$20.00
Released
2026-09-22
Modality
text+image+file->text

About Anthropic: Claude Opus 5.5

Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code...

Call Anthropic: Claude Opus 5.5

Via OpenRouter: one base URL for every provider.

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-opus-5.5",
    "messages": [{"role": "user", "content": "Say hello"}]
  }'

Direct on Anthropic:

curl https://api.anthropic.com/chat/completions \
  -H "Authorization: Bearer $ANTHROPIC_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-opus-5.5",
    "messages": [{"role": "user", "content": "Say hello"}]
  }'

Anthropic keys

OpenRouter keys

OpenRouter keys work for anthropic/claude-opus-5.5 regardless of the upstream provider.