AI engineering glossary · Prompt context engineering
What is prompt caching?
Prompt caching (also called Context caching): A provider feature that stores the processed form of a long, repeated prompt prefix so later requests starting with the same text are cheaper and faster. It works best when stable parts such as the system prompt and documents come first and changing parts last.
Prompt caching: an example
A 20,000-token policy document placed at the start of every request is cached, so only the short question is processed fresh each time.
Related terms
More Prompt context engineering terms
- Prompt chaining
- Prompt compression
- Prompt engineering
- Prompt optimisation
- Prompt registry
- Prompt regression testing
- Prompt sensitivity
- Prompt template
Where you learn it
Prompt caching is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.