# Introduction

> What HotKV is, HotKV Cloud vs. On-Premise, and Redis protocol compatibility.

URL: https://docs.hotkv.com/introduction/

HotKV is a proprietary, multi-threaded, in-memory data store that speaks the
Redis wire protocol (RESP2 and RESP3) and adds a set of AI-native commands on
top: a prompt cache, a semantic cache, agent memory, a RAG pipeline, and LLM
cost and budget tracking. It is written from scratch in C++20.

Because HotKV speaks RESP2/RESP3, your existing Redis or Valkey clients,
`redis-cli`, and tooling connect to it without code changes beyond the
hostname. HotKV also ships 12 official client SDKs with typed wrappers for
its own exclusive and AI commands; see [Connecting and SDKs](https://docs.hotkv.com/sdks/index.md).

## What HotKV includes

- **Classic data types**: strings, lists, sets, hashes, sorted sets, streams,
  geospatial, bitmaps, and HyperLogLog, plus Lua scripting and pub/sub.
- **HotKV-exclusive commands** available on every plan: nanosecond-precision
  TTLs (`NEXPIRE`/`NTTL`), key tagging (`TAG.*`), native vector similarity
  search (`VSIM.*`, HNSW-indexed), hot key tracking, and a GCRA rate limiter.
- **AI and LLM features** on HotKV Cloud's Performance plan and above, or
  under an On-Premise license with the matching feature enabled: an exact
  prompt cache (`PCACHE`), a semantic cache (`SCACHE`), LLM usage stats and
  budgets, agent memory, a RAG pipeline, embedding de-duplication, and a set
  of smaller keyed caches for tool calls, guardrails, and reranking. See the
  [AI features guide](https://docs.hotkv.com/ai-features/index.md).
- **Governance features** on HotKV Cloud's Scale plan, or under an
  On-Premise license that includes them: replication, encryption at rest,
  a tamper-evident audit log, and multi-tenancy. See
  [Security](https://docs.hotkv.com/security/index.md).
- **Roles and single sign-on** under an On-Premise license that includes
  them: log in through an LDAP directory or an OpenID Connect provider, and
  give logins roles that say which commands and keys they can use. See
  [Roles and single sign-on](https://docs.hotkv.com/operate/iam/index.md).

The full list, with exact syntax and which plan or license feature each
command needs, is in the [command reference](https://docs.hotkv.com/commands/index.md).

## HotKV Cloud vs. HotKV On-Premise

HotKV is sold two ways. Both run the same server binary and the same
command set; they differ in who operates it and how it is licensed.

<div className="table-scroll">
<table>
<thead>
<tr><th>&nbsp;</th><th>HotKV Cloud</th><th>HotKV On-Premise</th></tr>
</thead>
<tbody>
<tr>
  <td>Who runs it</td>
  <td>HotKV Ltd, on Google Cloud</td>
  <td>You, on your own servers or cloud account</td>
</tr>
<tr>
  <td>Get started</td>
  <td>Sign up in the <a href="https://portal.hotkv.com/register">portal</a></td>
  <td>Contact <a href="mailto:sales@hotkv.com">sales@hotkv.com</a> for a license</td>
</tr>
<tr>
  <td>Plans</td>
  <td>Starter, Performance, and Scale</td>
  <td>Licensed per the agreed feature set</td>
</tr>
<tr>
  <td>Billing</td>
  <td>Monthly or yearly in USD, priced live per region at checkout</td>
  <td>Commercial agreement with HotKV Ltd</td>
</tr>
<tr>
  <td>Operations</td>
  <td>Provisioning, upgrades, and monitoring handled for you, plus daily backups on Performance and Scale</td>
  <td>You control data residency, network access, and upgrade timing</td>
</tr>
</tbody>
</table>
</div>

Start with whichever fits how you want to operate it:

- [Quick start: HotKV Cloud](https://docs.hotkv.com/quickstart-cloud/index.md) if you want a managed
  instance running in minutes.
- [Quick start: On-Premise](https://docs.hotkv.com/quickstart-onpremise/index.md) if you want to run
  HotKV yourself, including in an air-gapped environment.

## Redis protocol compatibility

HotKV implements RESP2 and RESP3, including `HELLO` protocol negotiation,
so Redis and Valkey client libraries, `redis-cli`, `redis-cli --cluster`,
and GUI tools connect to it unmodified. The command reference notes which
commands are part of that standard surface and which are HotKV-exclusive or
enterprise/AI additions; HotKV's own SDKs additionally expose typed helpers
for every exclusive and AI command family. See
[Connecting and SDKs](https://docs.hotkv.com/sdks/index.md) for connection strings and examples in
each supported language, and the [command reference](https://docs.hotkv.com/commands/index.md) for
the full command list.

## Next steps

- [Quick start: HotKV Cloud](https://docs.hotkv.com/quickstart-cloud/index.md)
- [Quick start: On-Premise](https://docs.hotkv.com/quickstart-onpremise/index.md)
- [Clustering](https://docs.hotkv.com/clustering/index.md): a cluster of several nodes, with automatic failover
- [AI features guide](https://docs.hotkv.com/ai-features/index.md)
- [Command reference](https://docs.hotkv.com/commands/index.md)