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Claude Sonnet 4
anthropicanthropic/claude-sonnet-4
How TheRouter serves this differently from the vendor
As the vendor operates it
Anthropic's lifecycle table lists the native Claude API id 'claude-sonnet-4-20250514' as retired on Anthropic-operated platforms after a 2026-04-14 deprecation notice and 2026-06-15 retirement date. Anthropic recommends migrating to 'claude-sonnet-4-6'.
On TheRouter
TheRouter still keeps the public model page and OpenAI-compatible id 'anthropic/claude-sonnet-4' for customers who need a stable reference, but new integrations should route to 'anthropic/claude-sonnet-4.6' because the upstream retirement can affect live availability and support guarantees.
API guide
Chat completion
cURL
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"anthropic/claude-sonnet-4","messages":[{"role":"user","content":"Hello"}]}'Extended thinking
Enable extended thinking via the reasoning parameter (low/medium/high) or by including a thinking budget in the request.
cURL
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"anthropic/claude-sonnet-4","messages":[{"role":"user","content":"Solve this step by step"}],"reasoning":{"effort":"high"}}'Part of
Recent coverage
Fact ledger — every claim on this page traces here
| source | URL | retrieved | |
|---|---|---|---|
| Release date | www.anthropic.com ↗ | 2026-05-25 | verified |
| Anthropic model id | aws.amazon.com ↗ | 2026-05-25 | verified |
| Training cutoff | — | — | unknown |
| Context window | platform.claude.com ↗ | 2026-09-10 | verified |
| Max output tokens | www.anthropic.com ↗ | 2026-05-25 | verified |
| Reasoning modes | www.anthropic.com ↗ | 2026-05-25 | verified |
| Deployment | aws.amazon.com ↗ | 2026-05-25 | verified |
| License | — | — | verified |
| SWE-bench Verified | www.anthropic.com ↗ | 2026-05-25 | verified |
| GPQA Diamond | www.anthropic.com ↗ | 2026-05-25 | verified |
| MMMLU | www.anthropic.com ↗ | 2026-05-25 | verified |
| MMMU | www.anthropic.com ↗ | 2026-05-25 | verified |
| AIME | www.anthropic.com ↗ | 2026-05-25 | verified |
| OSWorld | www.anthropic.com ↗ | 2026-05-25 | verified |
| Anthropic deprecates Claude Sonnet 4 on the Claude API | platform.claude.com/model-deprecations ↗ | 2026-09-10 | verified |
| Claude Sonnet 4.5 released at the same $3/$15 Sonnet price tier | anthropic.com/news ↗ | 2026-09-10 | verified |
| Should I start a new TheRouter integration on Claude Sonnet 4? | platform.claude.com ↗ | 2026-09-10 | to verify |
| What changed since the original Sonnet 4 launch page? | www.anthropic.com ↗ | 2026-09-10 | to verify |
| Does TheRouter's OpenAI-compatible API surface change the Anthropic retirement status? | platform.claude.com ↗ | 2026-09-10 | to verify |