Dataset Diff & Change Detector MCP server

Dataset Diff & Change Detector (Remote MCP Server)

Compare two versions of the same list of JSON rows and get exactly what changed. Hand it yesterday's price list and today's, last week's product feed and this week's, or two exports of the same CRM, name the field that identifies a row, and it tells you which rows were added, removed or changed, down to which fields moved on each one.

Built for AI agents. No install, no API key, no signup. Connect by URL and call it.

https://dataset-diff-detector.nerolabs.workers.dev/mcp

Free to use while in early access.

What it does

One call compares a before snapshot (oldRows) with an after snapshot (newRows):

1. Matches rows across the two sides on keyFields, such as sku, id or email (one field or several). Without a key it matches on full row content, so an edited row shows as one removed row plus one added row.
2. Compares every field on each matched pair, minus any ignoreFields (timestamps that always differ), or only the compareFields you name.
3. Returns one row per difference with its status, key, oldValues, newValues and changedFields, plus a summary counting added, removed, changed and unchanged rows. Turn on includeUnchanged to get the unchanged rows back too.

Comparison is exact, so nothing is quietly glossed over: "24.99" as text and 24.99 as a number count as a change, as do "Blue" and "blue ", and null becoming a value. Nested objects compare by value, whatever order their keys are in.

It is honest about messy input. The summary warns when a key value appears twice on one side (the last row is kept and the count is reported), when rows have no key field at all, and when a field you named appears in no row, which is usually a typo.

Tools

Connect

Claude Code

claude mcp add --transport http dataset-diff-detector https://dataset-diff-detector.nerolabs.workers.dev/mcp

Claude Desktop / claude.ai: Settings, Connectors, Add custom connector, paste the URL above.

Cursor, Windsurf, VS Code and other MCP clients

{
  "mcpServers": {
    "dataset-diff-detector": {
      "url": "https://dataset-diff-detector.nerolabs.workers.dev/mcp"
    }
  }
}

Example

Yesterday's and today's price list go in, with the scrape timestamp ignored:

{
  "oldRows": [
    {"sku": "A100", "title": "Blue Widget", "price": 19.99, "stock": 42, "scrapedAt": "2026-09-11T08:00:00Z"},
    {"sku": "A101", "title": "Red Widget", "price": "24.99", "stock": 0, "scrapedAt": "2026-09-11T08:00:00Z"},
    {"sku": "A102", "title": "Green Widget", "price": 15.5, "stock": 8, "scrapedAt": "2026-09-11T08:00:00Z"},
    {"sku": "A104", "title": "Purple Widget", "price": 9.99, "discount": null, "scrapedAt": "2026-09-11T08:00:00Z"},
    {"sku": "A105", "title": "Orange Widget", "price": 30, "stock": 3, "scrapedAt": "2026-09-11T08:00:00Z"}
  ],
  "newRows": [
    {"sku": "A100", "title": "Blue Widget", "price": 17.99, "stock": 30, "scrapedAt": "2026-09-12T08:00:00Z"},
    {"sku": "A101", "title": "Red Widget", "price": 24.99, "stock": 0, "scrapedAt": "2026-09-12T08:00:00Z"},
    {"sku": "A102", "title": "Green Widget", "price": 15.5, "stock": 8, "scrapedAt": "2026-09-12T08:00:00Z"},
    {"sku": "A104", "title": "Purple Widget", "price": 9.99, "discount": 0.1, "scrapedAt": "2026-09-12T08:00:00Z"},
    {"sku": "A106", "title": "Yellow Widget", "price": 12, "stock": 100, "scrapedAt": "2026-09-12T08:00:00Z"}
  ],
  "keyFields": ["sku"],
  "ignoreFields": ["s

Shortened. The full README is on GitHub.