YAML to CSV Converter Online 2026 - Fast, Secure & Private
Convert YAML lists and objects into CSV tables. Perfect for data analysis and spreadsheet imports. 100% client-side privacy. Free online tool.
Key Features
- ✅ Automatic flattening of nested maps
- ✅ Headers generated from keys
- ✅ Supports lists of objects
- ✅ Directly import into Excel/Sheets
How to Use
- Input your YAML list or object
- Anchors, aliases, and merge keys are resolved automatically before flattening
- Configure additional flattening options if necessary
- Generate the CSV file content
- Download or copy the result for spreadsheet use
Expert FAQ
- My YAML uses anchors and aliases to avoid repeating shared config blocks — are those resolved before flattening?
Yes — anchors (&name) and aliases (*name), along with merge keys (<<: *base), are fully resolved during parsing before the flattening step runs, so a value referenced via an alias in the source YAML appears as its actual resolved value in the corresponding CSV cell, not as literal alias syntax. Flattening operates on the final, resolved data, the same as YAML to JSON does. - Can it convert a single YAML object (not a list)?
Yes — a single mapping is treated as a one-row table, with its keys becoming column headers. A YAML list of mappings becomes a multi-row table the same way a JSON array of objects does when converted to CSV; the two source formats hit the same flattening logic once parsed. - What happens to nested mappings — like a "user" key containing its own "address" mapping?
Nested keys flatten using dot notation (user.address.city) so the data stays individually queryable in spreadsheet columns rather than collapsing into an unreadable blob — the same convention used by this site's JSON to CSV and XML to CSV converters, for consistency if you're working across formats. - A YAML value is explicitly null (~) — does that produce an empty cell or the literal text "null"?
An empty cell, matching how CSV represents "no value" in general — writing the literal text "null" into a cell would make it indistinguishable from a string value that happens to say "null", which is a worse outcome for anyone reading the CSV downstream expecting an actually-empty field to mean absence of data.
Technical Details
YAML's object model is a superset of JSON's — mappings, sequences, and scalars, plus anchors/aliases and merge keys with no JSON equivalent — so converting to CSV starts by fully resolving those YAML-only features (expanding alias references, merging <<: *base keys into their target mapping) before any flattening happens. The CSV output reflects the final, resolved data, never literal anchor/alias syntax, matching the same resolve-then-convert approach YAML to JSON uses. Once resolved, the converter walks the object tree the same way JSON to CSV does: nested mappings flatten to dot-notation columns (user.address.city) to keep values individually queryable rather than serialized into an opaque cell, and a list of mappings becomes one row per item with the union of all keys forming the header row — not just the first item's keys, since sampling only the first record would silently drop columns for later items with additional fields. A single (non-list) mapping is treated as a one-row table. YAML's explicit null (written as null, ~, or an empty value) becomes a genuinely empty CSV cell rather than the literal text "null" — writing out the word would make an intentionally-empty field indistinguishable from a string value that happens to contain the text "null", which loses real information for anyone consuming the CSV downstream. Since CSV has no comment syntax, any # comments in the source YAML are necessarily dropped; there's no lossless way to carry them into tabular output. Validate the result afterward with the CSV Validator, or clean up formatting with the CSV Formatter.