Comparison
Claude API: FastMetal vs contracting Anthropic directly
There are two ways to use Claude over an API: contract Anthropic directly, or go through a gateway like FastMetal. FastMetal serves an Anthropic-compatible /v1/messages endpoint, so the official SDK and Claude Code work as they are, with only the base URL and API key changed.
Direct contracts win on speed of access to Anthropic's newest features. FastMetal wins on JPY billing with qualified invoices, and on using Claude alongside other providers' models under one key. Claude's main models are in the FastMetal catalog.
At a glance
| Aspect | FastMetal | Anthropic direct |
|---|---|---|
| Billing and invoices | Prepaid in JPY or USD, chosen per account. Card, or Japanese bank transfer for JPY; qualified invoices on JPY purchases | Billed in USD |
| API compatibility | Anthropic-compatible /v1/messages. The official SDK and Claude Code work unchanged | The official API and SDK |
| Models and providers | Claude's main models, plus other providers' models on the same key | Claude only. New models and betas arrive here first |
| Automatic routing | Set the model to auto and it picks the cheapest model that covers what the request needs, falling back to the next candidate on failure | One provider, so you name the model yourself |
| Modalities | Text, image, and video generation and structured decisions. Also reachable over MCP | Text generation and image input. No image or video generation |
| Operational burden | Many providers, one account | Simple if Anthropic is your only provider |
| Language and support | Japanese UI, docs, and support | Primarily English |
| Data flow | Requests are relayed to Anthropic | Requests go directly to Anthropic |
When going direct fits
- You want new models and betas on day one, or you need the full official API surface, including batch processing and organization controls.
- Your volume is large enough to negotiate discounts or an enterprise agreement with Anthropic.
- You have settled on Claude alone and have no plans to compare it with other providers' models.
When FastMetal fits
- You need JPY billing and Japanese qualified invoices, instead of pushing USD card charges through accounting.
- You use Claude Code or the official SDK and want zero code changes. Switching is an environment-variable change.
- You want Claude next to Gemini and other providers' models, compared under one key.
New Anthropic features can take time to reach FastMetal. See the models page for the Claude models currently available.
This comparison reflects public information as of September 2026.
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