Quickstart

sheets.fast is spreadsheet software built for agents. One request creates a durable, addressable workbook. No account needed to start.

1. Create a workbook

curl -X POST https://sheets.fast/api/v1/workbooks \
  -H 'content-type: application/json' -d '{"name": "Q3 pipeline"}'

The response includes the workbook ID and its URL. The ID is the URL:

{
  "id": "wbk_a8Kx92mQ3Fpq",
  "url": "https://sheets.fast/wbk_a8Kx92mQ3Fpq",
  "claimed": false,
  "expiresAt": "2026-09-05T00:00:00.000Z",
  "sheets": ["Sheet1"]
}

Open the URL in a browser to see and edit the grid. Anonymous workbooks expire in 7 days unless a signed-in user claims them. Requests made with an API key or OAuth token create permanent workbooks in your workspace.

If you already have the data, send it with the create call and skip the second request entirely:

curl -X POST https://sheets.fast/api/v1/workbooks \
  -H 'content-type: application/json' -d '{
  "name": "Q3 pipeline",
  "rows": [["Region", "Revenue"], ["East", 1200], ["West", 800]]
}'

Find your workbooks

Search by name or description, browse a folder by name, or list what is unfiled. Every result says which folder it lives in.

curl 'https://sheets.fast/api/v1/workbooks?q=pipeline' -H 'x-api-key: sk_live_…'
curl 'https://sheets.fast/api/v1/workbooks?folder=Finance' -H 'x-api-key: sk_live_…'
curl 'https://sheets.fast/api/v1/workbooks?folder=' -H 'x-api-key: sk_live_…'   # unfiled

GET /api/v1/folders lists folders with a full path (Finance/2026/Q3) and a count of the workbooks filed in each.

2. Write cells

Bulk writes take an anchor cell plus a 2D array. Values starting with = are Excel-compatible formulas. Markdown in cells renders in the grid.

Ranges accept E:E for a whole column and 2:2 for a whole row, resolved against the data that is actually there. Any cell or range may name its sheet: Summary!A1, Summary!A1:D50. A qualified reference is never ambiguous, so it needs no sheet field.

sheet accepts an index or a sheet name, anywhere it appears. In a workbook with more than one sheet a write must say which one: there is no assumed default, because assuming the first sheet is how data gets overwritten. The error lists the sheets to choose from.

curl -X POST https://sheets.fast/api/v1/workbooks/wbk_a8Kx92mQ3Fpq/cells \
  -H 'content-type: application/json' -d '{
  "start": "A1",
  "rows": [
    ["region", "revenue"],
    ["East", 1200],
    ["West", 800],
    ["total", "=SUM(B2:B3)"]
  ],
  "format": [{"range": "A1:B1", "bold": true}]
}'

The response returns the evaluated values of the written cells and the new revision. Sparse writes take an ops array of cell and value pairs instead.format styles ranges: bg, color, bold, italic, size, align, numFmt. Manage structure with POST /workbooks/{id}/sheets: add, rename, delete sheets, and insert_rows, delete_rows, insert_columns, delete_columns. Formula references shift automatically.

3. Read a range

curl 'https://sheets.fast/api/v1/workbooks/wbk_a8Kx92mQ3Fpq/cells?range=A1:B3'

4. Query with SQL

Each sheet is a table. One aggregate query replaces many reads.

curl -X POST https://sheets.fast/api/v1/workbooks/wbk_a8Kx92mQ3Fpq/query \
  -H 'content-type: application/json' \
  -d '{"sql": "SELECT region, SUM(revenue) FROM \"Sheet1\" GROUP BY 1"}'