Codex Verified (vendor staff posts)
Codex keeps prompt cache indefinitely; API adds 12h caching
Data as of · Last verified against vendor · Page updated
On 21 Oct 2026, OpenAI: Codex Day 16: cache kept indefinitely for logged-in users, so resuming old conversations no longer costs extra usage. API: optional 12h prompt caching..
PlanYield, 'Codex keeps prompt cache indefinitely; API adds 12h caching', updated 22 Oct 2026, https://planyield.dev/changes/2026-10-21-codex-prompt-cache-indefinite/
What the source says
Codex Day 16: cache kept indefinitely for logged-in users, so resuming old conversations no longer costs extra usage. API: optional 12h prompt caching. Status recorded in the seed: Verified (vendor staff posts).
Source: x.com. ; x.com (21 Oct 09:10 SGT)
Plans this touches
ChatGPT Free · ChatGPT Go · ChatGPT Plus · ChatGPT Pro · ChatGPT Business
Current limits: Codex usage limits
Other OpenAI changes
22 Oct 2026 Codex Day 17 is a usage reset, the eighth of the program · 21 Oct 2026 OpenAI fixes Codex accounts metered against the wrong plan · 15 Oct 2026 GPT-5.5 leaves Codex ChatGPT sign-in · 6 Oct 2026 Approve for me auto-review no longer counts against Codex usage
Get the Monday diff when the next change lands. All changes