Direct answer
The human-readable model name is Claude Sonnet 4.5. Its API model ID depends on the provider and route. For Anthropic’s direct Claude API, the documented version-specific ID is claude-sonnet-4-5-20250929, with the alias claude-sonnet-4-5. Don’t assume that ID works with another provider’s API. (Anthropic model overview)
Production status: Anthropic lists Sonnet 4.5 as deprecated and says it retires November 30, 2026. Check the provider’s current availability and migration guidance before adopting it for a new integration. (Anthropic model overview)
Claude Sonnet 4.5 IDs and routes by provider
| Provider or route | Model ID | Request route or note |
|---|---|---|
| Anthropic Claude API | claude-sonnet-4-5-20250929 |
Messages API: POST https://api.anthropic.com/v1/messages. The shorter alias is claude-sonnet-4-5. (Anthropic API overview) |
| Amazon Bedrock Runtime | anthropic.claude-sonnet-4-5-20250929-v1:0 |
AWS examples use the Bedrock Runtime client with InvokeModel and Converse. This is a Bedrock ID, not the Anthropic API ID. (AWS Bedrock model card) |
| Bedrock geo inference | us.anthropic.claude-sonnet-4-5-20250929-v1:0; eu.anthropic.claude-sonnet-4-5-20250929-v1:0; au.anthropic.claude-sonnet-4-5-20250929-v1:0; jp.anthropic.claude-sonnet-4-5-20250929-v1:0 |
Check region availability and residency requirements before choosing a geo inference ID. (AWS Bedrock model card) |
| Bedrock global inference | global.anthropic.claude-sonnet-4-5-20250929-v1:0 |
Global Cross-Region routing can route worldwide; check that this fits your residency requirements and source-region availability. (AWS Bedrock model card) |
| Inworld | anthropic/claude-sonnet-4-5-20250929 |
Inworld’s example uses https://api.inworld.ai/v1/chat/completions with an Inworld API key. Its listing says it is going away November 30, 2026. This is not an Anthropic-direct request. (Inworld model listing) |
Use the ID documented for the provider and endpoint you actually call. AWS distinguishes In-Region, Geo Cross-Region, and Global Cross-Region routing; availability differs by endpoint. Check the supported source region and your data-residency requirements before selecting a Bedrock inference ID. (AWS Bedrock model card)
Lifecycle and production planning
Retirement notices are provider-specific. Anthropic says its Claude API model is deprecated and retires November 30, 2026. AWS separately marks the Bedrock model Legacy in all Regions and lists April 8, 2027 as its Bedrock end-of-life date; AWS says requests to that Bedrock model will fail after that date. These dates describe different services, so don’t apply one provider’s notice to another. (Anthropic model overview; AWS Bedrock model card)
Inworld’s listing also says “Going away Nov 30, 2026”; that notice applies to the Inworld listing, not to Anthropic’s or AWS’s service. Confirm current availability and migration guidance with your provider before relying on a route. (Inworld model listing)
Relevant limits
AWS lists a 200K-token context window and 64K-token maximum output for its Bedrock listing. These are model specifications, not guarantees of your account’s rate limits or quotas. (AWS Bedrock model card)
Sources
Claude Sonnet 4.5 — Claude Platform Docs
API overview — Claude Platform Docs