# selfstore vs Automerge
Source: https://selfstore.dev/compare/automerge

Automerge is a document CRDT with history and time travel; selfstore is the persistence loop around a document. Complementary, the same way Yjs is.

## What Automerge is

A JSON-document CRDT with a compact binary format, a Rust core compiled to
WASM, and something Yjs does not emphasise: **history**. An Automerge document
keeps its changes, so you can ask what a document looked like before, and
attribute who changed what. `automerge-repo` adds the networking and storage
adapters around it.

If your requirement is "never lose a concurrent edit, and let me travel back",
this is the tool, and selfstore does not attempt either.

## What selfstore is

The loop around whatever your data is: an IndexedDB working copy, portable
encrypted ZIP backups on an [open spec](https://selfstore.dev/docs/format), durable homes on storage
the user already owns, no server. Its own merge is last-write-wins with no
history at all - an overwrite is final locally, which is stated plainly in the
[limits](https://selfstore.dev/docs/sync).

## They compose

An Automerge document saved with `Automerge.save()` is bytes, and bytes are
what a selfstore file holds. Store each change (or each saved document) under
the id of its own content and selfstore's union-by-id merge carries every
device's copy through to the other side, where Automerge folds them back into
one document. The reasoning is identical to the [Yjs page](https://selfstore.dev/compare/yjs), which
carries the worked example.

| | Automerge | selfstore |
| --- | --- | --- |
| Solves | Concurrent edits + history | Durability, portability, destinations |
| History / time travel | Yes | No, keep dated backups instead |
| Local persistence | An adapter you add | Built in |
| Encryption | Yours to build | Built in, AES-256-GCM + Argon2id |
| User-holdable backup | The document itself | A spec'd ZIP of the whole app |
| Size on the wire | Compact binary | Whole-state, no delta sync |

## Use Automerge alone when

- History and attribution are requirements, not nice-to-haves.
- The document IS the application, and a `.automerge` file is the artefact your
  users care about.

## Use both when

- You want the merge quality of a CRDT and the things around it selfstore
  already solved: encryption at rest and in flight, a destination the user
  picks, a backup that opens in any archive tool, and screens to connect one.

Map of this site for a model: https://selfstore.dev/llms.txt
Every page in one file: https://selfstore.dev/llms-full.txt