José Arroyo

Chilean/French software engineer. Blog posts, deep dives and experiments.

How prompt caching works in Claude Code and how to make the most of it

Claude Code caches your prompts as you go. When continuing an existing conversation, the previous part of your prompt that is already cached is billed only at 10% of the full cost. By default, Claude Code in billed-per-token setups sets a prompt cache TTL of 5 mins. This means that if you take longer than 5 mins to continue a Claude Code session, you'll pay full price for the whole conversation every turn.