# Project Backup Verifier

> Check a Bundlekeep backup file by file and get a restore checklist. Open a Bundlekeep backup: the tool recomputes the SHA-256 checksum of every project file, lists what each file is and what it leaves out, writes a restore checklist per app and can extract one project file for download.

Part of usefulweb.app (https://usefulweb.app/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://bundlekeepbackupverifier.usefulweb.app/ (interactive tool at https://bundlekeepbackupverifier.usefulweb.app/tool)
- JSON API: POST https://bundlekeepbackupverifier.usefulweb.app/api/v1/calculate with a JSON object of inputs (schema: https://bundlekeepbackupverifier.usefulweb.app/api/v1/tool)
- OpenAPI: https://bundlekeepbackupverifier.usefulweb.app/openapi.json
- MCP (Streamable HTTP): https://bundlekeepbackupverifier.usefulweb.app/mcp - tool `bundlekeep_backup_verifier`

## Inputs
- backup (textarea): Backup (JSON text) - Paste a .bundlekeep.json backup, or upload the file below.
- backupFile (file): Backup file (optional) - Used instead of the pasted text when given.
- extract (text): File to extract (optional) - Exact file name from the backup; the tool returns that project file for download.

## Method
- Validates the Bundlekeep format (version 1), unique file names, JSON content and the limits of 200 files, 10 MB per file and 50 MB in total.
- Recomputes SHA-256 for each file and compares it with the checksum recorded when the file was added: verified (identical), changed (different) or no checksum (older backups).
- Recognises the app and format of each file and lists the same warnings as the Project File Identifier (documents or media outside the file, kept secrets, unknown format).
- The restore checklist groups files by app with workspace links. Restoring means downloading a file and opening it in its app; nothing is written into an app.