Claude Sonnet 4.5 is Anthropic's state-of-the-art model offering high intelligence, speed, and efficiency for code generation, writing, and logical analysis. Supports text and image inputs. Token-based pricing: $1.80/M input tokens, $9.00/M output tokens. Two endpoints: standard async (/claude-sonnet-4-5) and live streaming (/claude-sonnet-4-5/stream) via SSE.
About this model
Claude Sonnet 4.5 is Anthropic's state-of-the-art model offering high intelligence, speed, and efficiency for code generation, writing, and logical analysis. It strikes the perfect balance between reasoning depth and execution speed. Pricing: $1.80 per million input tokens and $9.00 per million output tokens.
Cost analysis
| Provider | Cost | Notes |
|---|---|---|
| muapiapp | $1.80/M input tokens, $9.00/M output tokens | Token-based billing. Minimum $0.00035 per call. ~60% of official Anthropic pricing. |
| Anthropic (official) | ~$3.00/M input tokens, ~$15.00/M output tokens | Official pricing via api.anthropic.com. |
| Fal.ai | Not available | Claude Sonnet 4.5 is not available on Fal.ai. |
Token-based billing. Minimum $0.00035 per call. ~60% of official Anthropic pricing.
Official pricing via api.anthropic.com.
Claude Sonnet 4.5 is not available on Fal.ai.
** Competitor pricing is estimated based on similar model architectures and usage tiers.
Configuration schema
| Parameter | Type | Description | Default |
|---|---|---|---|
| Prompt | string | The user message or instruction. | Review this code and suggest improvements for performance and readability. |
| Image URL | string | Optional image URL for multimodal requests. | undefined |
| System Prompt | string | Optional system-level instruction to guide model behavior. | You are an expert software architect. |
The user message or instruction.
Review this code and suggest improvements for performance and readability.Optional image URL for multimodal requests.
undefinedOptional system-level instruction to guide model behavior.
You are an expert software architect.Developer documentation
POST /api/v1/claude-sonnet-4-5 — returns request_id, poll for result via /api/v1/predictions/{id}/result.
POST /api/v1/claude-sonnet-4-5/stream — returns a live SSE stream. Each chunk: data: {"choices":[{"delta":{"content":"text"}}]}, ending with data: [DONE].
See Streaming Documentation for full code examples.
Frequently asked
Pricing is token-based: $1.80 per million input tokens and $9.00 per million output tokens. The minimum charge per call is $0.00035. Actual cost is deducted after each call based on token counts returned by the model.
Yes. Pass an image_url in the request body to include an image as part of the user message.