Unofficial · Prices from OpenAI docs · Updated: 2026-09-05
OpenAI Batch vs Flex: Same 50% Off, Different Shape
OpenAI Batch and Flex both offer about 50% off Standard rates, but they are not the same product: Batch is an asynchronous batch API, Flex is a synchronous half-price path with higher latency. For agent evaluations and interactive flows where Batch cannot run, prefer Flex.
Flex is sync half-price. Batch is async half-price.
Both cut Standard list rates by about 50%. They are not interchangeable products. Flex is a synchronous half-price path on the same chat-style / Responses API — you send a request, wait longer, and get a completion. Batch is an asynchronous batch API — you upload a job, it runs later, you download results.
Agent evaluations do not fit Batch
If the harness is interactive — agent loops, tool calls, evals that need a completion in the same turn — Batch cannot run. Prefer Flex there. Use Batch when you can wait on a queued job and do not need live turns.
Estimate the token mix on the GPT-6 Astra pricing calculator, then confirm list rates on the LLM Pricing Leaderboard.