# Project Backup Builder

> Combine usefulweb project files into one Bundlekeep backup with checksums. Give a list of project files from any usefulweb premium apps: the tool packs them unchanged into one Bundlekeep backup, names each file after its project, skips identical copies and records a SHA-256 checksum per file.

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://bundlekeepbackupbuilder.usefulweb.app/ (interactive tool at https://bundlekeepbackupbuilder.usefulweb.app/tool)
- JSON API: POST https://bundlekeepbackupbuilder.usefulweb.app/api/v1/calculate with a JSON object of inputs (schema: https://bundlekeepbackupbuilder.usefulweb.app/api/v1/tool)
- OpenAPI: https://bundlekeepbackupbuilder.usefulweb.app/openapi.json
- MCP (Streamable HTTP): https://bundlekeepbackupbuilder.usefulweb.app/mcp - tool `bundlekeep_backup_builder`

## Inputs
- name (text): Backup name
- projects (textarea): Project files (JSON array) - Either project objects, or {"name": "file.json", "content": "<project text>"} to keep the exact text and name.
- notes (textarea): Backup notes (optional)
- created (date): Backup date (optional) - Recorded as the backup and file date. Empty = no date, so the same files always give the identical backup.

## Method
- Each entry is kept as text: entries given with "content" stay byte for byte, project objects are written as indented JSON. Entries must be JSON objects or arrays of at most 10 MB.
- File names come from the entry or from the project name plus the app’s extension (for example kitchen.kerfwise.json); clashing names get a number, names without folders or reserved characters are enforced.
- Identical files (same SHA-256 of the text) are added once. Limits: 200 files and 50 MB per backup.
- The backup only records a date when you enter one, so the same files and settings always produce the identical backup file and checksum.
- The backup is the Bundlekeep format described in project.schema.json; open it in Bundlekeep to review, verify and restore single files.