AI_SLANG_ENTRY
Prompt Caching Meaning
The builder trick of reusing repeated prompt context so long instructions, schemas, examples, or documents do not get billed and processed from scratch every time.
What does Prompt Caching mean?
The builder trick of reusing repeated prompt context so long instructions, schemas, examples, or documents do not get billed and processed from scratch every time.
Prompt caching means the API can recognize reused context and process it more efficiently. It is useful for apps that send the same instructions, tools, or reference material across many requests.
Origin and usage
Became everyday LLM API vocabulary as providers added caching for repeated prompt prefixes and developers started optimizing long-context apps around it.
Source type: product-term. Last checked: 2026-07-09.
Current model-provider and developer-platform term; official API docs describe prompt caching as an optimization for repeated prompt prefixes, with provider-specific behavior and pricing.
Examples
- Prompt caching made the support agent cheap enough to keep the full policy manual in context.
- If every request starts with the same giant system prompt, check whether prompt caching is actually working.