Convert CSV to YAML Online

Convert CSV files to YAML directly in your browser. Download clean, human-readable YAML — no upload required.

About converting CSV to YAML

CSV to YAML is a developer conversion. The typical case is a spreadsheet of values that has to become a config or content file: feature flags, translation strings, a product list for a Hugo data folder, Ansible variables or test fixtures. The table lives in a spreadsheet because it is easier to edit there, and YAML is generated for the tool that reads it.

The output is a YAML sequence of mappings: one "- " item per CSV row, with each header as a key. It uses block style and never wraps lines, so long values stay on one line and Git diffs stay readable.

YAML's implicit typing is the classic trap, and the output guards against it. Strings that a YAML parser would read as something else are quoted: dates like '2026-03-02', codes like '00123', and words such as NO, yes or on that YAML 1.1 parsers treat as booleans. The country code NO for Norway therefore stays a string. The CSV side has its own version of the problem, though. A column holding only yes/no or T/F values is read as boolean before the YAML is written, so it comes out as true/false.

Not sure which format you need? Read the JSON vs YAML comparison.

Worked example

A small orders export with an ID, a customer name, a date, an amount (one missing) and a true/false flag, converted with the default settings.

Input (CSV)

order_id,customer,order_date,amount,shipped
1001,Acme Ltd,2026-03-02,249.5,true
1002,Brightside Co,2026-03-02,1200,false
1003,Acme Ltd,2026-03-05,89.99,true
1004,Northwind,2026-03-07,,false

Output (YAML)

- order_id: 1001
  customer: Acme Ltd
  order_date: '2026-03-02'
  amount: 249.5
  shipped: true
- order_id: 1002
  customer: Brightside Co
  order_date: '2026-03-02'
  amount: 1200
  shipped: false
- order_id: 1003
  customer: Acme Ltd
  order_date: '2026-03-05'
  amount: 89.99
  shipped: true
- order_id: 1004
  customer: Northwind
  order_date: '2026-03-07'
  amount: null
  shipped: false

What changes when you convert CSV to YAML

Each CSV row becomes a list item starting with "- ", and each column becomes a key: value line under it.
order_date values are quoted ('2026-03-02') so YAML loaders keep them as strings instead of converting them to dates.
Numbers and booleans are written bare: amount: 249.5, shipped: true.
Order 1004 has amount: null. The key is kept rather than dropped.
Keys appear as written in the header. A key YAML could misread, such as y or no, is quoted too.

Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.

Frequently Asked Questions

Will the YAML load back with the same types?

Mostly. Numbers, booleans and nulls round-trip. Dates come back as strings because they are quoted; PyYAML and js-yaml would otherwise turn an unquoted 2026-03-02 into a date object. If you want real dates, remove the quotes in that column.

What happens to cells that contain line breaks?

A value with Unix line breaks is written as a YAML literal block (|-), so each line stays readable. If the breaks are Windows-style CRLF, the value is written as a double-quoted string with \r\n escapes instead.

Is YAML a sensible target for a large CSV?

Not really. Every key is repeated for every row, and YAML parsers are much slower than JSON parsers. Keep YAML for config-sized tables of a few hundred rows that people edit by hand. For bulk data, convert to JSON, NDJSON or Parquet instead.

Related Tools

Convert YAML to CSV Online

Convert YAML files to CSV format directly in your browser. No upload required — your data never leaves your device.

YAML Viewer Online

View and inspect YAML files directly in your browser. Browse rows, check column names and data types — no upload required, your data stays on your device.

CSV Viewer Online

View and inspect CSV files directly in your browser. Browse rows, check column names and data types — no upload required, your data stays on your device.

Validate CSV Files Online

Validate CSV file structure in your browser. Check null counts, distinct values, and data types for every column — no upload required.

Deduplicate CSV Files Online

Remove duplicate rows from CSV files instantly in your browser. No upload, no server — 100% private.

Convert CSV to Parquet Online

Convert CSV files to Parquet format directly in your browser. No upload required — your data never leaves your device.

Convert CSV to Excel Online

Convert CSV files to Excel format directly in your browser. No upload required — your data never leaves your device.

Convert CSV to JSON Online

Convert CSV files to JSON format directly in your browser. No upload required — your data never leaves your device.