OpenAI Batch API vs Anthropic Message Batches: Bulk Completions Compared (2026)

Short answer: these aren't direct rivals — they're each vendor's bulk/async path, and the right one usually follows which model you want. OpenAI's Batch API and Anthropic's Message Batches both let you submit large jobs asynchronously at a significant discount versus real-time calls, trading latency (results within a processing window) for cost. Choose by the model you need (GPT vs Claude); if you want both behind one interface, route through a gateway.

At a glance

OpenAI Batch APIAnthropic Message Batches

PurposeAsync bulk completionsAsync bulk messages Discount vs real-timeYes (substantial)Yes (substantial) LatencyWithin a processing windowWithin a processing window ModelGPT familyClaude family Best forBulk jobs on OpenAIBulk jobs on Claude

When to use a batch API at all

If you have a large, latency-tolerant job — classifying a dataset, generating embeddings or summaries in bulk, offline evaluation — submitting it as a batch costs meaningfully less than firing thousands of real-time requests. You upload the requests, the provider processes them within a window, and you collect results. The cost savings are the whole point; the price is that it's not instant.

OpenAI Batch API: submit a file of requests, get results back within the processing window at a discount — ideal for bulk GPT jobs. The request format mirrors the standard chat API; see OpenAI Function Calling 完全指南 for the call shape.

Anthropic Message Batches: the equivalent for Claude — batch many Messages-API calls asynchronously at reduced cost. Pick by which Claude tier fits; see Claude 系列对比.

How to choose

Bulk job and you want GPT models? OpenAI Batch API.

Bulk job and you want Claude models? Anthropic Message Batches.

Need both / want to avoid lock-in? Route via a gateway — see LiteLLM vs Portkey.

Cost-efficient small-tier bulk work? Pair batching with GPT-4o mini vs Claude Haiku.

FAQ

How much cheaper is batch? Both offer a substantial discount over real-time; check current rates on each vendor's pricing page. How fast are results? Within a processing window, not instant — designed for latency-tolerant jobs. Can I mix providers? Not natively — use a gateway to abstract both.

Verdict

Treat these as the same idea implemented by two vendors: cheap, asynchronous bulk processing. The decision is really "which model do I want for this bulk job?" — GPT points to OpenAI's Batch API, Claude to Anthropic's Message Batches. For maximum savings, combine batching with a small model tier, and use a gateway if you need both.

---

*Last updated: June 2026. Verify batch discounts and processing windows on the OpenAI and Anthropic sites.*