Project Backup Verifier

Check a Bundlekeep backup file by file and get a restore checklist.

Backup (JSON text)

{
  "format": "bundlekeep",
  "version": 1,
  "name": "Workshop backup",
  "items": [
    {
      "name": "base-cabinet-600.kerfwise.json",
      "content": "{\n  \"format\": \"kerfwise\",\n  \"version\": 1,\n  \"name\": \"Base cabinet 600\",\n  \"cabinets\": [\n    {\n      \"id\": \"c1\",\n      \"name\": \"Base 600\",\n      \"type\": \"base\",\n      \"x\": 0,\n      \"y\": 0,\n      \"rot\": 0,\n      \"params\": {\n        \"width\": 600,\n        \"height\": 870,\n        \"depth\": 560,\n        \"doorCount\": 1,\n        \"shelfCount\": 1,\n        \"topType\": \"rails\",\n        \"countertop\": false\n      }\n    }\n  ]\n}",
      "app": "kerfwise",
      "format": "kerfwise",
      "sha256": "e6f17c489b32c4e577c7c857a650bbbbbf8a1d2f1c9daaf8718ce7f6e0e3e6dc",
      "source": "template"
    },
    {
      "name": "led-with-series-resistor.ohmforge.json",
      "content": "{\n  \"format\": \"ohmforge\",\n  \"version\": 1,\n  \"name\": \"LED with series resistor\",\n  \"parts\": [\n    {\n      \"id\": \"BT1\",\n      \"kind\": \"battery\",\n      \"x\": 0,\n      \"y\": 0,\n      \"rot\": 0,\n      \"flip\": false,\n      \"props\": {\n        \"voltage\": \"9\",\n        \"rint\": \"1\"\n      }\n    },\n    {\n      \"id\": \"SW1\",\n      \"kind\": \"switch\",\n      \"x\": 4,\n      \"y\": -6,\n      \"rot\": 0,\n      \"flip\": false,\n      \"props\": {\n        \"closed\": true,\n        \"ron\": \"10m\"\n      }\n    },\n    {\n      \"id\": \"R1\",\n      \"kind\": \"resistor\",\n      \"x\": 10,\n      \"y\": -6,\n      \"rot\": 0,\n      \"flip\": false,\n      \"props\": {\n        \"value\": \"390\",\n        \"power\": \"0.25\",\n        \"tolerance\": \"5%\"\n      }\n    },\n    {\n      \"id\": \"D1\",\n      \"kind\": \"led\",\n      \"x\": 14,\n      \"y\": -4,\n      \"rot\": 90,\n      \"flip\": false,\n      \"props\": {\n        \"colour\": \"red\",\n        \"imax\": \"20m\"\n      }\n    },\n    {\n      \"id\": \"GND1\",\n      \"kind\": \"ground\",\n      \"x\": 0,\n      \"y\": 4,\n      \"rot\": 0,\n      \"flip\": false,\n      \"props\": {}\n    }\n  ],\n  \"wires\": [\n    {\n      \"id\": \"w1\",\n      \"pts\": [\n        [\n          0,\n          -2\n        ],\n        [\n          0,\n          -6\n        ],\n        [\n          2,\n          -6\n        ]\n      ]\n    },\n    {\n      \"id\": \"w2\",\n      \"pts\": [\n        [\n          6,\n          -6\n        ],\n        [\n          8,\n          -6\n        ]\n      ]\n    },\n    {\n      \"id\": \"w3\",\n      \"pts\": [\n        [\n          12,\n          -6\n        ],\n        [\n          14,\n          -6\n        ]\n      ]\n    },\n    {\n      \"id\": \"w4\",\n      \"pts\": [\n        [\n          14,\n          -2\n        ],\n        [\n          14,\n          4\n        ],\n        [\n          0,\n          4\n        ],\n        [\n          0,\n          2\n        ]\n      ]\n    }\n  ],\n  \"notes\": [\n    {\n      \"id\": \"n1\",\n      \"x\": 17,\n      \"y\": -7,\n      \"text\": \"R = (9 V − 1.9 V) / 0.02 A ≈ 355 Ω → 390 Ω\"\n    },\n    {\n      \"id\": \"n2\",\n      \"x\": 17,\n      \"y\": -5,\n      \"text\": \"Try 47 Ω to see the LED burn out\"\n    }\n  ],\n  \"sim\": {\n    \"mode\": \"op\",\n    \"tran\": {\n      \"tstop\": \"10m\",\n      \"tstep\": \"10u\",\n      \"method\": \"trap\",\n      \"uic\": false\n    },\n    \"ac\": {\n      \"fstart\": \"10\",\n      \"fstop\": \"1Meg\",\n      \"ppd\": 20\n    },\n    \"dc\": {\n      \"start\": \"0\",\n      \"stop\": \"10\",\n      \"step\": \"0.1\"\n    },\n    \"speed\": 0.001\n  },\n  \"description\": \"Sizing an LED resistor: R = (Vs − Vf) / If = (9 V − 1.9 V) / 20 mA ≈ 355 Ω → 390 Ω (E12), giving ≈ 18 mA.\",\n  \"instruments\": {\n    \"meter\": {\n      \"mode\": \"A\",\n      \"part\": \"D1\"\n    }\n  }\n}",
      "app": "ohmforge",
      "format": "ohmforge",
      "sha256": "57ea75125b44a8784e6b84b321cf3ae296a7a7f7584606a4e30067278bb0a51b",
      "source": "template"
    },
    {
      "name": "3-station-line.twinworks.json",
      "content": "{\n  \"format\": \"twinworks-project\",\n  \"version\": 1,\n  \"name\": \"3-station line\",\n  \"active\": \"base\",\n  \"scenarios\": [\n    {\n      \"id\": \"base\",\n      \"name\": \"Baseline\",\n      \"notes\": \"\",\n      \"model\": {\n        \"format\": \"twinworks-model\",\n        \"version\": 1,\n        \"name\": \"3-station line\",\n        \"description\": \"A simple serial line: random arrivals, three machines with triangular cycle times and two small buffers. The classic starting point.\",\n        \"settings\": {\n          \"horizon\": 28800,\n          \"warmup\": 1800,\n          \"seed\": 12345,\n          \"replications\": 5,\n          \"confidence\": 0.95,\n          \"sampleInterval\": null,\n          \"currency\": \"EUR\",\n          \"timeUnit\": \"s\",\n          \"lengthUnit\": \"m\",\n          \"gridSize\": 0.5\n        },\n        \"products\": [\n          {\n            \"id\": \"P1\",\n            \"name\": \"Bracket\",\n            \"color\": \"#2563eb\",\n            \"priority\": 0,\n            \"materialCost\": 4.2,\n            \"price\": 19,\n            \"routing\": []\n          }\n        ],\n        \"calendars\": [],\n        \"pools\": [],\n        \"nodes\": [\n          {\n            \"id\": \"SRC1\",\n            \"type\": \"source\",\n            \"name\": \"Raw parts\",\n            \"x\": 2,\n            \"y\": 6,\n            \"rotation\": 0,\n            \"calendar\": null,\n            \"routing\": \"first\",\n            \"note\": \"\",\n            \"arrival\": \"interval\",\n            \"interval\": {\n              \"type\": \"exponential\",\n              \"mean\": 55\n            },\n            \"firstAt\": 0,\n            \"batchSize\": 1,\n            \"maxArrivals\": null,\n            \"mix\": [],\n            \"schedule\": [],\n            \"repeatEvery\": null,\n            \"whenBlocked\": \"queue\"\n          },\n          {\n            \"id\": \"M1\",\n            \"type\": \"machine\",\n            \"name\": \"Saw\",\n            \"x\": 6,\n            \"y\": 6,\n            \"rotation\": 0,\n            \"calendar\": null,\n            \"routing\": \"first\",\n            \"note\": \"\",\n            \"servers\": 1,\n            \"cycle\": {\n              \"type\": \"triangular\",\n              \"min\": 35,\n              \"mode\": 40,\n              \"max\": 50\n            },\n            \"cycleByProduct\": {},\n            \"setup\": null,\n            \"idealCycleTime\": null,\n            \"batchSize\": 1,\n            \"scrapPct\": 0,\n            \"failure\": null,\n            \"maintenance\": null,\n            \"operator\": null,\n            \"costPerHour\": 38,\n            \"costPerPart\": 0\n          },\n          {\n            \"id\": \"B1\",\n            \"type\": \"buffer\",\n            \"name\": \"Buffer 1\",\n            \"x\": 10,\n            \"y\": 6,\n            \"rotation\": 0,\n            \"calendar\": null,\n            \"routing\": \"first\",\n            \"note\": \"\",\n            \"capacity\": 5,\n            \"discipline\": \"fifo\"\n          },\n          {\n            \"id\": \"M2\",\n            \"type\": \"machine\",\n            \"name\": \"Mill\",\n            \"x\": 14,\n            \"y\": 6,\n            \"rotation\": 0,\n            \"calendar\": null,\n            \"routing\": \"first\",\n            \"note\": \"\",\n            \"servers\": 1,\n            \"cycle\": {\n              \"type\": \"triangular\",\n              \"min\": 40,\n              \"mode\": 48,\n              \"max\": 58\n            },\n            \"cycleByProduct\": {},\n            \"setup\": null,\n            \"idealCycleTime\": null,\n            \"batchSize\": 1,\n            \"scrapPct\": 0,\n            \"failure\": null,\n            \"maintenance\": null,\n            \"operator\": null,\n            \"costPerHour\": 65,\n            \"costPerPart\": 0\n          },\n          {\n            \"id\": \"B2\",\n            \"type\": \"buffer\",\n            \"name\": \"Buffer 2\",\n            \"x\": 18,\n            \"y\": 6,\n            \"rotation\": 0,\n            \"calendar\": null,\n            \"routing\": \"first\",\n            \"note\": \"\",\n            \"capacity\": 5,\n            \"discipline\": \"fifo\"\n          },\n          {\n            \"id\": \"M3\",\n            \"type\": \"machine\",\n            \"name\": \"Deburr\",\n            \"x\": 22,\n            \"y\": 6,\n            \"rotation\": 0,\n            \"calendar\": null,\n            \"routing\": \"first\",\n            \"note\": \"\",\n            \"servers\": 1,\n            \"cycle\": {\n              \"type\": \"triangular\",\n              \"min\": 30,\n              \"mode\": 38,\n              \"max\": 45\n            },\n            \"cycleByProduct\": {},\n            \"setup\": null,\n            \"idealCycleTime\": null,\n            \"batchSize\": 1,\n            \"scrapPct\": 0,\n            \"failure\": null,\n            \"maintenance\": null,\n            \"operator\": null,\n            \"costPerHour\": 30,\n            \"costPerPart\": 0\n          },\n          {\n            \"id\": \"OUT1\",\n            \"type\": \"sink\",\n            \"name\": \"Finished goods\",\n            \"x\": 26,\n            \"y\": 6,\n            \"rotation\": 0,\n            \"calendar\": null,\n            \"routing\": \"first\",\n            \"note\": \"\"\n          }\n        ],\n        \"links\": [\n          {\n            \"id\": \"L1\",\n            \"from\": \"SRC1\",\n            \"to\": \"M1\",\n            \"weight\": 1,\n            \"products\": [],\n            \"kind\": \"normal\",\n            \"qty\": 1\n          },\n          {\n            \"id\": \"L2\",\n            \"from\": \"M1\",\n            \"to\": \"B1\",\n            \"weight\": 1,\n            \"products\": [],\n            \"kind\": \"normal\",\n            \"qty\": 1\n          },\n          {\n            \"id\": \"L3\",\n            \"from\": \"B1\",\n            \"to\": \"M2\",\n            \"weight\": 1,\n            \"products\": [],\n            \"kind\": \"normal\",\n            \"qty\": 1\n          },\n          {\n            \"id\": \"L4\",\n            \"from\": \"M2\",\n            \"to\": \"B2\",\n            \"weight\": 1,\n            \"products\": [],\n            \"kind\": \"normal\",\n            \"qty\": 1\n          },\n          {\n            \"id\": \"L5\",\n            \"from\": \"B2\",\n            \"to\": \"M3\",\n            \"weight\": 1,\n            \"products\": [],\n            \"kind\": \"normal\",\n            \"qty\": 1\n          },\n          {\n            \"id\": \"L6\",\n            \"from\": \"M3\",\n            \"to\": \"OUT1\",\n            \"weight\": 1,\n            \"products\": [],\n            \"kind\": \"normal\",\n            \"qty\": 1\n          }\n        ],\n        \"cost\": {\n          \"overheadPerHour\": 20,\n          \"scrapDisposal\": 0\n        },\n        \"notes\": []\n      }\n    }\n  ]\n}",
      "app": "twinworks",
      "format": "twinworks-project",
      "sha256": "4b094bfae3303ae29c7a57e3f3c835725ce4150c8dd350d6ca62a2aa20959008",
      "source": "template"
    },
    {
      "name": "name-tag.threadsmith.json",
      "content": "{\n  \"format\": \"threadsmith\",\n  \"version\": 1,\n  \"name\": \"Name tag\",\n  \"hoop\": \"130x180\",\n  \"palette\": [\n    {\n      \"id\": \"sapphire\",\n      \"name\": \"Sapphire\",\n      \"hex\": \"#0f4c81\"\n    },\n    {\n      \"id\": \"coral\",\n      \"name\": \"Coral\",\n      \"hex\": \"#e8705a\"\n    },\n    {\n      \"id\": \"ivory\",\n      \"name\": \"Ivory\",\n      \"hex\": \"#fffbf0\"\n    }\n  ],\n  \"objects\": [\n    {\n      \"id\": \"frame\",\n      \"name\": \"Frame\",\n      \"kind\": \"rect\",\n      \"color\": \"sapphire\",\n      \"x\": -45,\n      \"y\": -22,\n      \"w\": 90,\n      \"h\": 44,\n      \"r\": 8,\n      \"stitch\": {\n        \"type\": \"satin\",\n        \"mode\": \"border\",\n        \"width\": 3,\n        \"density\": 0.4\n      },\n      \"underlay\": {\n        \"center\": true\n      }\n    },\n    {\n      \"id\": \"hello\",\n      \"name\": \"Hello\",\n      \"kind\": \"text\",\n      \"color\": \"coral\",\n      \"text\": \"Hello, my name is\",\n      \"x\": 0,\n      \"y\": -7,\n      \"size\": 6,\n      \"font\": \"single\",\n      \"align\": \"center\",\n      \"stitch\": {\n        \"type\": \"running\",\n        \"length\": 1.8,\n        \"bean\": true\n      }\n    },\n    {\n      \"id\": \"name\",\n      \"name\": \"Name\",\n      \"kind\": \"text\",\n      \"color\": \"sapphire\",\n      \"text\": \"Ada\",\n      \"x\": 0,\n      \"y\": 14,\n      \"size\": 16,\n      \"font\": \"single\",\n      \"align\": \"center\",\n      \"spacing\": 1,\n      \"stitch\": {\n        \"type\": \"satin\",\n        \"width\": 2.4,\n        \"density\": 0.36\n      },\n      \"underlay\": {\n        \"center\": true\n      }\n    }\n  ]\n}",
      "app": "threadsmith",
      "format": "threadsmith",
      "sha256": "2c85ac2d4b00a28a099fb597b0fb21decbf41538dca1fac2e3ca3c5a6178dfee",
      "source": "template"
    }
  ]
}

Paste a .bundlekeep.json backup, or upload the file below.

Backup file (optional)

Used instead of the pasted text when given.

More options

File to extract (optional)

Exact file name from the backup; the tool returns that project file for download.

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Try an example: Verify the workshop example backup · Extract the circuit from a backup · Spot a changed file

More about this tool

How it works

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.

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.

Sources

Bundlekeep backup format (project.schema.json) (usefulweb.site)
FIPS 180-4 Secure Hash Standard (SHA-256) (NIST)

Part of Bundlekeep

Bundlekeep Local project backup

Back up projects from every usefulweb app into one file, check it and restore any part.

Open Bundlekeep

How to use the Project Backup Verifier

Check every file of a Bundlekeep backup against its checksum, see what each file is and get a restore checklist.

What it is for

A backup is only useful if it is intact when you need it. The Project Backup Verifier opens a Bundlekeep backup and checks each project file against the SHA-256 checksum that was recorded when the file was added. It also tells you which app opens each file, warns about parts that live outside a project, and writes a restore checklist grouped by app.

Use it for regular checks of stored backups — monthly from a script, for example — or to pull a single project out of a backup without opening the workspace. Give the exact file name in File to extract and the result contains that file as a download.

The verifier does not repair files, and a verified checksum does not promise that a future app version still opens an old project.

Worked example

The first example verifies the "Workshop backup" from the Bundlekeep templates. The tool answered: "Checked 4 files: 4 verified, 0 without a checksum."

Worked example
File	App	Bytes	Checksum
base-cabinet-600.kerfwise.json	Kerfwise	413	Verified
led-with-series-resistor.ohmforge.json	Ohmforge	2,580	Verified
3-station-line.twinworks.json	Twinworks	6,237	Verified
name-tag.threadsmith.json	Threadsmith	1,446	Verified

Together that is 10,676 bytes from 4 apps, and the callout confirmed that every file matches its checksum. The restore checklist starts with "# Restore checklist: Workshop backup" and lists one section per app with a link to its workspace.

The third example adds a single space inside the cabinet project. Its size becomes 414 bytes and the result changes to "Checked 4 files: 1 file changed since it was added", with the cabinet marked "Changed" and a warning not to rely on it until you have checked it. One space is enough — that is the point of a checksum.

How to read the result

Verified means the file is byte for byte the one that was added. Changed means the text differs. No checksum appears for files from backups made before checksums existed; saving the backup again in the workspace adds them.
Apps and the table show what you would get back, and where to open it.
The restore checklist (Markdown) has one tick box per file, the format and project name, and every warning.
Download appears when you asked to extract a file.

Tips and common mistakes

Upload the backup file instead of pasting it when it is larger than a few megabytes; the file field accepts up to 55 MB.
The extract name must match exactly, including the extension, for example led-with-series-resistor.ohmforge.json.
A "Changed" file is not necessarily lost. Compare it with another copy of the backup before you delete anything.
Keep at least two copies of important backups and verify both.
The workspace performs the same check whenever you open a backup, entirely in your browser.

FAQ

What does a changed checksum mean?

The file's text is different from when it was added — a damaged download, a sync conflict or a manual edit.

Can it verify backups made by the first Bundlekeep release?

Yes. Those files have no checksums yet, so they are reported as "No checksum" rather than verified.

Is the backup stored on the server?

No. It is read to answer the request; only an extracted file is kept as a download for about two hours.

How do I restore from the checklist?

Download each file, open its app with the link in the checklist and use the app's command for opening a project file.

Guide last updated: October 31, 2026

For scripts and AI agents

JSON API: POST https://bundlekeepbackupverifier.usefulweb.app/api/v1/calculate (same calculation as this page)
Interface description: OpenAPI 3.1 · AI guide: llms.txt
MCP server (Streamable HTTP): https://bundlekeepbackupverifier.usefulweb.app/mcp · tool name bundlekeep_backup_verifier

Example request

curl -s -X POST https://bundlekeepbackupverifier.usefulweb.app/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{}'

Feedback · ideas & bug reports welcome