> For the complete documentation index, see [llms.txt](https://chrondb.avelino.run/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://chrondb.avelino.run/getting-started/index.md).

# Introduction

**Welcome to ChronDB!** A modern, Git-based database that remembers everything.

## What is ChronDB?

ChronDB is a chronological database built on Git's powerful architecture that gives your data complete version history. Think of it as "Git for your database" - every change is tracked, every version is accessible, and you can time-travel through your data's complete history.

ChronDB is licensed under the GNU Affero General Public License v3.0 (AGPLv3), ensuring improvements deployed as hosted services remain available to the community.

## Why Choose ChronDB?

* **Complete History** - Never lose data again. Every change is preserved in your database's timeline.
* **Time Travel** - Query your data as it existed at any point in time.
* **Branching & Merging** - Create isolated environments for testing, development, or experimentation.
* **Multiple Interfaces** - Connect through Clojure, REST API, Redis protocol, or even PostgreSQL protocol.
* **ACID Compliance** - Enjoy full transaction support with commit, rollback, and consistency guarantees.
* **Schema-less** - Store any JSON-compatible data without rigid structure requirements.
* **Lucene-Powered Search** - Execute full-text, composite, and geospatial queries using Lucene's production-grade indexing engine.

## How It Works

ChronDB leverages Git's internal structure as a storage engine:

```
Repository (database)
  └── Branches (schemas/environments)
       └── Directories (tables)
            └── Files (documents as JSON)
```

Each document is a file in the Git repository, and each change creates a commit in the history. This gives you all the power of Git for your database:

* See diffs between versions
* Browse commit history
* Create branches for development
* Merge changes between branches
* Tag important versions
* Hook into events

## Quick Example

Here's how simple it is to use ChronDB with its Clojure API:

```clojure
;; Create/connect to a database
(def db (chrondb/create-chrondb))

;; Create a user document
(chrondb/save db "user:1" {:name "Alice" :email "alice@example.com"})

;; Update the document
(chrondb/save db "user:1" {:name "Alice" :email "alice@example.com" :role "admin"})

;; Time travel: see how the document looked yesterday
(def yesterday (chrondb/get-at db "user:1" "2023-07-15T00:00:00Z"))

;; See all versions of the document
(def history (chrondb/history db "user:1"))
```

## Choose Your Interface

ChronDB speaks multiple protocols so you can connect with your favorite tools:

* **Native Clojure API** - Direct, powerful access from Clojure applications
* **REST API** - HTTP interface for any language or client
* **Redis Protocol** - Use Redis clients to connect directly
* **PostgreSQL Protocol** - Connect with SQL clients and tools

## Start Your Journey

New to ChronDB? Here's how to get started:

1. [Quick Start Guide](https://github.com/avelino/chrondb/blob/main/docs/quickstart/README.md) - Up and running in minutes
2. [Core Concepts](https://github.com/avelino/chrondb/blob/main/docs/data-model/README.md) - Understand ChronDB's data model
3. [Examples](https://github.com/avelino/chrondb/blob/main/docs/examples/README.md) - See ChronDB in action
4. [API Reference](https://github.com/avelino/chrondb/blob/main/docs/api/README.md) - Complete API documentation

## Ready to dive in?

→ [Get Started Now](https://github.com/avelino/chrondb/blob/main/docs/quickstart/README.md)

## Community Resources

* **Official Documentation**: [chrondb.avelino.run](https://chrondb.avelino.run/)
* **Join our Community**: [Discord](https://discord.com/channels/1099017682487087116/1353399752636497992)
* **Discussions & Ideas**: [GitHub Discussions](https://github.com/avelino/chrondb/discussions)


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