Build Hour: Prompt Caching

Original Description

Build faster, cheaper, and with lower latency using prompt caching. This Build Hour breaks down how prompt caching works and how to design your prompts to maximize cache hits. Learn what’s actually being cached, when caching applies, and how small changes in your prompts can have a big impact on cost and performance.

Erika Kettleson (Solutions Engineer) covers:

• What prompt caching is and why it matters for real-world apps

• How cache hits work (prefixes, token thresholds, and continuity)

• Best practices like using the Responses API and prompt_cache_key

• How to measure cache hit rate, latency, and token savings

• Customer Spotlight: Warp (ttps://www.warp.dev/) led by Suraj Gupta (Team Lead) to explain the impact of prompt caching

👉 Prompt Caching Docs: https://platform.openai.com/docs/guides/prompt-caching

👉 Prompt Caching 101 Cookbook: https://developers.openai.com/cookbook/examples/prompt_caching101

👉 Prompt Caching 201 Cookbook: https://developers.openai.com/cookbook/examples/prompt_caching_201

👉 Follow along with the code repo: http://github.com/openai/build-hours

👉 Sign up for upcoming live Build Hours: https://webinar.openai.com/buildhours

00:00 Introduction

02:37 Foundations, Mechanics, API Walkthrough

12:11 Demo: Batch Image Processing

16:55 Demo: Branching Chat

26:02 Demo: Long Running Compaction

32:39 Cache Discount Pricing Overview

36:03 Customer Spotlight: Warp

49:37 Q&A