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Key Compression

With the key compression plugin, documents will be stored in a compressed format which saves up to 40% disc space. For compression the npm module jsonschema-key-compression is used. It compresses json-data based on its json-schema while still having valid json. It works by compressing long attribute-names into smaller ones and backwards.

The compression and decompression happens internally, so when you work with a RxDocument, you can access any property like normal.

Enable key compression

The key compression plugin is a wrapper around any other RxStorage.

  • You first have to wrap your RxStorage with the key compression plugin
  • Then use that as RxStorage when calling createRxDatabase()
  • Then you have to enable the key compression by adding keyCompression: true to your collection schema.
import { wrappedKeyCompressionStorage } from 'rxdb/plugins/key-compression';
import { getRxStorageDexie } from 'rxdb/plugins/storage-dexie';

const storageWithKeyCompression = wrappedKeyCompressionStorage({
storage: getRxStorageDexie()

const db = await createRxDatabase({
name: 'mydatabase',
storage: storageWithKeyCompression

const mySchema = {
keyCompression: true, // set this to true, to enable the keyCompression
version: 0,
primaryKey: 'id',
type: 'object',
properties: {
id: {
type: 'string',
maxLength: 100 // <- the primary key must have set maxLength
/* ... */

/* ... */