CSV Data Dictionary
Free toolPaste or upload a CSV. Get a documented data dictionary: column names, inferred types, sample values and null rates, ready to copy as Markdown, JSON Schema or a basic SQL CREATE TABLE statement. Everything is processed in your browser: nothing is uploaded to RA Software Apps servers.
Data dictionary
| Column | Type | Null rate | Unique | Sample values |
|---|
Export
Markdown
JSON Schema
SQL
How to use it
- Paste the CSV or upload the file; the first row is treated as the header.
- Review the generated dictionary: each column name, its inferred type, sample values and null rate.
- Copy the result as Markdown, as JSON Schema or as a SQL CREATE TABLE statement using the table name you provide.
What it works out and how
The tool reads the CSV rows, infers each column type from its values and counts how many cells are empty. From that it builds documentation you can paste into a README, a validation schema or a starting point for creating the table. The SQL is deliberately basic: adjust lengths, keys and indexes before using it.
Frequently asked questions
How is a column type decided?
From the content: if every non-empty value fits as a number, date or boolean, that type is assigned; if values are mixed, the column is treated as text.
Does it handle large files?
It works with whatever your browser can hold in memory. For files of many megabytes, pasting a representative sample of rows is usually enough.
Does my data leave the browser?
No. The CSV is processed locally, so you can use it with internal data without uploading it to any service.