YAML to CSV converter

Q: How is a two-step conversion checked?

Your input is converted to JSON first, then to the target format. Each step has its own independent check, and both must pass. The checks of both steps are listed under every result.

Q: Is my data uploaded?

No. Everything runs in your browser, in a background worker. Nothing is sent to a server.

Q: How do I convert YAML to CSV online?

Paste your YAML or open a file on the left (or click Example). The CSV appears on the right as you type, already checked. Copy it, or download it as a file. Nothing is uploaded.

Q: Can the CSV output be wrong?

Every result is checked before it is shown (the checks are listed on this page). If a check fails, the page says "Review needed" and why, instead of presenting the output as correct, and anything that cannot convert exactly is named in the notes.

Convert YAML to CSV: a YAML list of records becomes a table, with nested values flattened into dotted column names.

Converter

DelimiterFlatten nested objects

YAML

Open file

CSV

Waiting for input

What you get

Convert a YAML list to CSV: one row per record and one column per key, nested values as dot-named columns.
A list inside a wrapper key (items: [...]) is found automatically.
Checked twice: YAML read strictly, then the CSV parsed back and every cell compared.
Private and free: everything runs in your browser, nothing is uploaded, and there is no sign-up.

How each result is checked

Step 1: Your YAML is parsed strictly as YAML 1.2: duplicate keys and syntax errors are rejected with the line number.
Step 1: The JSON output is parsed back and compared with the parsed YAML, value by value.
Step 2: The CSV is parsed back, including quoted commas, quotes and line breaks.
Step 2: Every cell is compared with the value it came from.

What can't convert exactly

Anchors (&), aliases (*) and merge keys (<<) are expanded into full copies, because JSON has no references.
Comments and custom tags such as !Ref are not data, so they are not carried over. You get a warning when this happens.
Several documents separated by --- become one JSON array.
CSV is text only: numbers and booleans are written as text and null becomes an empty cell.
Arrays inside a row are written as JSON text in one cell.
When rows have different keys, all keys become columns and missing values are left empty.
An object that wraps one list, such as {"data": [...]} or the root element of an XML file, is unwrapped: the list becomes the rows, and the result names where they were found and any single values left out beside them.

Questions

How is a two-step conversion checked?

Your input is converted to JSON first, then to the target format. Each step has its own independent check, and both must pass. The checks of both steps are listed under every result.

Is my data uploaded?

No. Everything runs in your browser, in a background worker. Nothing is sent to a server.

How do I convert YAML to CSV online?

Paste your YAML or open a file on the left (or click Example). The CSV appears on the right as you type, already checked. Copy it, or download it as a file. Nothing is uploaded.

Can the CSV output be wrong?

Every result is checked before it is shown (the checks are listed on this page). If a check fails, the page says "Review needed" and why, instead of presenting the output as correct, and anything that cannot convert exactly is named in the notes.