---
title: Production catalogs
description: Understand merging, compact message keys, asset generation, and SSR behavior.
order: 20
toc:
  - id: merge-order
    title: Merge order
  - id: build-output
    title: Build output
  - id: server-rendering
    title: Server rendering
---

## Merge order {#merge-order}

Package sources are merged in configured order, followed by the application catalog. An application therefore translates only its own messages unless it intentionally customizes package copy.

> Import only the locale sources used by the application. Block-specific entries do not import catalogs from unrelated features.

## Build output {#build-output}

During production builds, the plugin:

1. merges configured catalogs for every locale;
2. creates one shared schema from semantic message IDs;
3. replaces those IDs with deterministic compact keys;
4. emits one content-hashed JSON asset per locale.

The private schema is diagnostic build state and is not shipped to the browser.

## Server rendering {#server-rendering}

The SSR bundle embeds the matching compact catalog. Browser navigation loads only the selected locale asset, so adding languages does not duplicate every translation in the main application bundle.