Observed source change · OpenAI
OpenAI cache policy documentation changed
Published documentation; runtime behavior and legal interpretation not established.
Last unchanged check: 2026-10-20T17:50:05Z
First changed check: 2026-10-20T19:55:04Z
Before
For GPT-5.6 and later, cache writes cost 1.25× the standard, uncached input-token rate. Subsequent reads cost 0.1× that rate on most of these models and 0.05× on [GPT-6.1 Sol](https://developers.openai.com/api/docs/models/gpt-6.1-sol). At the 0.1× read rate, writing a prefix once and fully reusing it once costs 1.35× its ordinary input cost, compared with 2× for processing it twice without caching. Across ten requests, one write and nine full reads cost 2.15× at that rate, compared with 10× without caching. Cache entries are not stored indefinitely. A later request can reuse a cached …
After
For GPT-5.6 and later, cache writes cost 1.25× the standard, uncached input-token rate for the default 30-minute lifetime. In the Responses API, you can choose a [12-hour minimum lifetime](#cache-lifetime) at a write rate of 2.5× ordinary input. Subsequent reads cost 0.1× the ordinary input rate on most of these models and 0.05× on [GPT-6.1 Sol](https://developers.openai.com/api/docs/models/gpt-6.1-sol), regardless of the selected lifetime. At the 0.1× read rate with 30-minute writes, writing a prefix once and fully reusing it once costs 1.35× its ordinary input cost, compared with 2× for processing it twice …
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Raw before SHA-256: 74dc45350d5de0e7eef80b0b09d67b733a73170275f1bacb0760e066a4254480
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