Prompt Caching for LLMs: Design a Stable Prefix That Earns Its Keep
A stable prompt prefix can make repeated context reusable. The benefit depends on useful repetition, careful versioning, and measured behavior.
Read the articleThe cache knowledge directory
The worldbehindthe cache.
A clearer view of AI memory, token reuse, browser caching, and search discovery. Explore the systems that make information worth reusing.
22Connected topic guides
10In-depth Lab articles
05Paths to explore
Cache atlas / volume 01✳
Context makes reuse meaningful.
Prompt prefixes, model versions, and access scope determine which work is eligible to be reused.
Freshness lives in the rules.
HTTP responses, validators, and application-managed stores each have a different role in the browser.
Discovery leaves different evidence.
A search index, a result observation, and a saved page copy answer three different questions.
KEY → CONTEXT → REUSEExplore the layers ↗
CACHE KEYS✳PROMPT REUSE✳TOKEN CONTEXT✳AGENT MEMORY✳BROWSER CACHE✳SEARCH INDEXES✳AI DISCOVERY✳CACHE APIs✳
One word. Different systems.
Every cache tells
a different story.
Before the architecture, get the vocabulary right. Learn what is retained, what a lookup finds, and which conditions allow another use.
01 / FOUNDATIONS
Know the cache.
Map a request to reusable work. Understand keys, freshness, invalidation, and why a stored entry can still be the wrong answer.
Explore the foundations02 / INTELLIGENCE
Understand AI reuse.
Connect prompt context, token accounting, chat sessions, and agent memory without treating every stored result as the same thing.
Explore AI & agents03 / DISCOVERY
Follow the evidence.
Read the signals behind crawling, indexing, search results, and AI answers. Keep observations separate from assumptions.
Explore search & discoveryThe complete index / 22 topics
Pick your layer.
Find your next question.
Start with a concept you recognize. Every guide connects to the related ideas, practical decisions, and deeper reading around it.
AI & agents
08 guidesPrompt context, token accounting, chat history, model behavior, and agent state.
Search & discovery
10 guidesSearch engines, SERP observations, AI answers, and useful visibility research.
Cache foundations
01 guidesKeys, context, freshness, and the basic decisions behind correct reuse.
Browser & HTTP
01 guidesResponse caching, validation, application storage, and the web browser.
Cache engineering
02 guidesPractical interfaces, service evaluation, lifecycle rules, and observable behavior.
Search & discovery
A result is only
part of the picture.
Explore the terminology and official documentation around the world’s major search systems.
Understand crawl evidence, page identity, and search inclusion.
Bing
Distinguish indexed information from a live URL inspection.
Yandex
Follow the stages from discovery to a query-specific result.
Baidu
Keep indexed information separate from saved observations.
These are independent educational guides. Search-engine names identify the subjects covered; the guides do not imply partnerships or provide live cache access. For a reproducible observation method, read the SERP cache index guide.
From concept to contract
A good key
is just the beginning.
Make the reuse decision visible. A cache record should connect its identity to the version, scope, and freshness rules that give it meaning.
- 01Define which requests are truly equivalent.
- 02Keep versions and access scope explicit.
- 03Plan for misses, updates, and invalidation.
Illustrative cache record / JSON
{
"key": "guide:cache-basics:en",
"source_version": "edition-01",
"scope": "public-reference",
"freshness_rule": "source-version-match",
"on_miss": "read-authoritative-source"
}A design example for learning. Explore the guide for lifecycle decisions.
Cache Index Lab
Less guesswork.
More understanding.
Browser Cache and HTTP Caching: Understand What Gets Reused
Follow one resource from its first download to a cache hit, a validation request, and an update—and learn which browser cache is involved.
Read the article
GEO and AI Search Visibility: Measure Evidence, Not Promises
Build a clear AI search measurement plan: define visibility, preserve answer context, review content, and keep cached observations separate from ranking claims.
Read the articleGood questions, clear answers
Before you
go deeper.
Start with the distinctions that make the rest of the directory easier to navigate.
What is CacheIndex.com?
CacheIndex.com is an independent learning directory. It connects cache architecture, AI reuse, browser behavior, search discovery, and practical engineering guides in one place.
Is a cache index the same as a search index?
A cache index helps locate reusable work under matching conditions. A search index supports retrieval of relevant documents. A system can use both, but their purposes and correctness rules differ.
Does prompt caching save a finished answer?
Prompt caching usually concerns input processing. Returning a stored final answer is a separate application-level choice with its own matching, freshness, and access requirements.
Can I access live search caches or an API here?
The site provides guides, examples, and references. It does not offer live search-engine cache access, account integrations, a hosted model, or a callable cache API.
Where should I start?
Begin with the Cache Index guide for the core vocabulary. Choose AI & agents, Browser & HTTP, Search & discovery, or Cache engineering when you are ready for a specific system.
Start with one good question.
Follow a topic, explore the tradeoffs, and go deeper in the Lab.