Last updated 2026-07-11 · model id anthropic/claude-sonnet-4.5
Anthropic's balanced flagship — coding and agents. Use it through CheaperLLM's OpenAI-compatible API — one key that also unlocks 612 other models, with free credit on signup and no subscription.
| CheaperLLM (pay-as-you-go) | Upstream list rate* | |
|---|---|---|
| Input, per 1M tokens | $3.66 | $3.00 |
| Output, per 1M tokens | $18.30 | $15.00 |
| Context window | 1,000,000 tokens | |
| Subscription required | None — pay per token; free credit on signup | |
*Provider/aggregator list rate at snapshot time. CheaperLLM bills the live upstream rate plus a 22% platform fee, which funds the free signup credit, 211 always-free models, the built-in chat app and unified billing across 56 providers. Rates shown are a 2026-07-11 snapshot; the live rate applies at request time.
Get a free API key — no cardfrom openai import OpenAI
client = OpenAI(base_url="https://api.cheaperllm.com/v1",
api_key="YOUR_CHEAPERLLM_KEY")
r = client.chat.completions.create(model="anthropic/claude-sonnet-4.5",
messages=[{"role": "user", "content": "Hello!"}])Or with curl:
curl https://api.cheaperllm.com/v1/chat/completions \
-H "Authorization: Bearer $CHEAPERLLM_KEY" -H "Content-Type: application/json" \
-d '{"model": "anthropic/claude-sonnet-4.5", "messages": [{"role":"user","content":"Hello!"}]}'$3.66 per 1M input tokens and $18.30 per 1M output tokens, billed pay-as-you-go. No monthly minimum or subscription (snapshot 2026-07-11).
Yes. New accounts get free credit with no card required, and it works on Claude Sonnet 4.5. There are also 211 always-free models in the same catalog.
Set base_url="https://api.cheaperllm.com/v1", use your CheaperLLM key, and pass model="anthropic/claude-sonnet-4.5". Existing OpenAI SDK code needs no other changes.