API Documentation

Authentication

All requests require an API key passed as a Bearer token in the Authorization header. Generate your key in Account settings.

Authorization: Bearer csviser_xxxxxxxxxxxxxxxxxxxx

Keys start with csviser_ and are shown only once at creation — store them securely.

Endpoint

POST https://csviser.com/api/v1/process

Accepts a CSV or XLSX file, applies the requested operations, and returns the processed file as a download. Files are processed entirely in memory — nothing is stored on our servers.

Parameters

Send as multipart/form-data.

Parameter	Type	Description
file	File *	CSV or XLSX file to process. XLSX is converted to CSV automatically.
fix[]	String[]	One or more operations to apply. Repeat the parameter for multiple values. Available values: `blank_rows` — remove fully empty rows `trim` — strip leading/trailing whitespace from cells `nulls` — normalize null variants (NULL, N/A, none…) to empty `encoding` — normalize to UTF-8, strip BOM `line_endings` — unify mixed CRLF + LF to LF `delimiter` — convert semicolon/tab/pipe to comma
dedup	String	Pass `1` to enable deduplication — all exact duplicate rows are removed, keeping only the first occurrence of each.
output_format	String	Output format: `csv` (default), `xlsx`, or `json`.
webhook_url	String	If provided, the request returns immediately with `{"queued":true,"job_id":"..."}` and the processed file is POSTed to this URL asynchronously in the background. Requests to private/internal IPs are blocked.
webhook_headers	String (JSON)	JSON object of extra headers to include in the webhook request. Used for endpoint authentication. Example: `{"Authorization":"Bearer tok","X-Secret":"abc"}`. Only applied when `webhook_url` is set.

Limits

Plan	Max rows per file
Free	500 rows
Pro	Unlimited

Rate limit: 10 requests per minute per API key, regardless of plan. Exceeding the limit returns 429 Too Many Requests. The window resets after 60 seconds.

Error responses

Errors are returned as JSON with an appropriate HTTP status code.

Status	Meaning
401 Unauthorized	Missing or invalid API key.
403 Forbidden	File exceeds the row limit for your plan.
429 Too Many Requests	Rate limit exceeded — more than 10 requests per minute from this API key.
422 Unprocessable	Missing file parameter or invalid XLSX.
500 Server Error	Processing failed. Check the `error` field for details.

{"error": "Row limit exceeded. This file has 1200 rows; free plan supports up to 500."}

Examples

Basic cleanup (blank rows + trim + nulls)

curl -X POST https://csviser.com/api/v1/process \
  -H "Authorization: Bearer csviser_xxxxxxxxxxxxxxxxxxxx" \
  -F "[email protected]" \
  -F "fix[]=blank_rows" \
  -F "fix[]=trim" \
  -F "fix[]=nulls" \
  -o cleaned.csv

Full cleanup + dedup + export as XLSX

curl -X POST https://csviser.com/api/v1/process \
  -H "Authorization: Bearer csviser_xxxxxxxxxxxxxxxxxxxx" \
  -F "[email protected]" \
  -F "fix[]=blank_rows" \
  -F "fix[]=trim" \
  -F "fix[]=nulls" \
  -F "fix[]=encoding" \
  -F "fix[]=line_endings" \
  -F "fix[]=delimiter" \
  -F "dedup=1" \
  -F "output_format=xlsx" \
  -o cleaned.xlsx

Export as JSON

curl -X POST https://csviser.com/api/v1/process \
  -H "Authorization: Bearer csviser_xxxxxxxxxxxxxxxxxxxx" \
  -F "[email protected]" \
  -F "fix[]=trim" \
  -F "output_format=json" \
  -o data.json

Send processed file to a webhook endpoint

Instead of downloading the result, POST it directly to your endpoint. Works with Zapier, Make, n8n, or your own backend.

curl -X POST https://csviser.com/api/v1/process \
  -H "Authorization: Bearer csviser_xxxxxxxxxxxxxxxxxxxx" \
  -F "[email protected]" \
  -F "fix[]=blank_rows" \
  -F "fix[]=trim" \
  -F "output_format=json" \
  -F "webhook_url=https://hooks.zapier.com/hooks/catch/123/abc/" \
  -F 'webhook_headers={"Authorization":"Bearer your-token"}'

API responds immediately — file is processed and delivered in the background:

{"queued": true, "job_id": "b2d3f1a8-..."}