Turn a CSV into a REST API

By Killian Helf, founder · Updated 19 October 2026 · Markdown

Sometimes a CSV is the whole database: a product catalog, a price list, a lead export. To use it from an app or an automation you usually need a server, a database and an endpoint. This guide turns a CSV into a REST API with filters, sorting and aggregates, without running any of that.

1. Upload the CSV

Sign in at app.datatomcp.com, then Add data → Upload a CSV (or Paste a link for a CSV that lives at a URL and should be re-fetched on refresh). The import report shows each column’s id and type. The column ids are what you use in queries.

2. Create an API key

Go to Account → API keys, name the key (for example production) and copy it. It starts with dtm_ and is shown once. Keys can be revoked at any time.

3. Query it

Every dataset has an id like ds_abc123, shown on its page and returned by GET /v1/datasets.

Rows with filters and sorting:

curl https://app.datatomcp.com/v1/datasets/ds_abc123/query \
  -H "Authorization: Bearer $DATATOMCP_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "where": [{ "column": "country", "op": "eq", "value": "France" }],
    "select": ["order_id", "order_date", "total"],
    "order_by": [{ "column": "total", "dir": "desc" }],
    "limit": 10
  }'

Aggregates:

curl https://app.datatomcp.com/v1/datasets/ds_abc123/query \
  -H "Authorization: Bearer $DATATOMCP_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "group_by": ["product"],
    "metrics": [
      { "fn": "count", "as": "orders" },
      { "fn": "sum", "column": "total", "as": "revenue" }
    ],
    "order_by": [{ "column": "revenue", "dir": "desc" }]
  }'

Each response has rows and a meta block: the dataset version, refreshed_at, rows_matched, rows_returned and truncated. Page through results with offset (up to 1,000 rows per request).

All endpoints

Errors are JSON with a stable code and a readable message, for example query_limit when the daily quota is reached.

Updating the data

Upload a new file to the same dataset (POST /v1/datasets/:id/refresh with Content-Type: text/csv), click Upload new version in the app, or use a CSV link and refresh it. The previous version is kept for rollback, and responses always tell you which version answered.

Limits

Free: 3 datasets, 100,000 rows each, 1,000 queries a day. Pro ($12 or €12 a month): 25 datasets, 2 million rows each, 50,000 queries a day. The same datasets are also available to AI agents as an MCP server.