Claude Sonnet 4.5

Overview

Frontier model from Anthropic, tuned for nuanced reasoning, long-horizon agentic work and careful instruction following with industry-leading safety behavior. Claude Sonnet 4.5 supports up to 200K tokens of context, native vision input, and an extended reasoning mode. Served through the FirmLink unified API with OpenAI-compatible endpoints.

API example

Fully OpenAI-compatible — just change the model field.

curl https://api.firmlinktech.com/v1/chat/completions \
  -H "Authorization: Bearer $FIRMLINK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-sonnet-4.5",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Pricing

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