CSV to YAML Converter Online — CSV to Block YAML

Convert CSV to a clean block-style YAML list of mappings — header names sanitised, types inferred, ready for Ansible vars, Kubernetes ConfigMaps, Helm values, and SSG data files.

Input CSV

YAML Output

What is a CSV to YAML converter?

A CSV to YAML converter turns a CSV file into a YAML sequence of mappings — one list item per row, with header names as keys. The OpenFormatter version emits clean block-style YAML, sanitises header names that contain spaces or hyphens, and only quotes values when YAML would otherwise misinterpret them.

YAML is the configuration language of modern infrastructure: Kubernetes manifests, Ansible playbooks, GitHub Actions workflows, Helm values files, and almost every static site generator's data layer. Engineers regularly need to seed those files from spreadsheet exports — server inventories, feature flags, environment matrices, content tables — and CSV to YAML is the fastest way to do it.

How to convert CSV to YAML online — 4 steps

Paste your CSV. The first row holds the header — those names become YAML keys, sanitised so they are valid identifiers.
Click Convert. Each row becomes a list item starting with -. Numbers, booleans, and null are emitted unquoted.
Verify quoting. Strings that contain colons, hashes, or other YAML reserved characters are auto-quoted to keep the document well-formed.
Nest under a parent key. If your manifest expects servers: or users:, prepend the key and indent the result by two spaces.

Sample CSV and YAML output

A simple server inventory — note how the integer port, the boolean enabled, and the unquoted role strings round-trip cleanly:

Input CSV

host,port,enabled,role
api-1,8080,true,primary
api-2,8081,true,replica
api-3,8082,false,maintenance

YAML Output

- host: api-1
  port: 8080
  enabled: true
  role: primary
- host: api-2
  port: 8081
  enabled: true
  role: replica
- host: api-3
  port: 8082
  enabled: false
  role: maintenance

Block-Style List

Output is a YAML sequence of mappings — one - per row — the standard format for Ansible vars, Kubernetes lists, and Helm values.

Smart Quoting

Values with colons, hashes, brackets, or leading whitespace are auto-quoted. Plain strings, numbers, and booleans stay unquoted for maximum readability.

Browser-Only

CSV parsing and YAML emission run in JavaScript on your machine. Inventory files, secrets, and configuration data never leave the device.

Common use cases

check_circleGenerating Ansible inventory or vars files from a server spreadsheet
check_circleSeeding Kubernetes ConfigMaps from a CSV of feature flags
check_circleCreating Helm chart values.yaml fragments from a release matrix
check_circleBuilding data files for Hugo, Jekyll, Eleventy, or Astro from CSV
check_circleProducing GitHub Actions matrix configurations from a CSV of jobs
check_circleConverting CSV test fixtures into YAML for Spec / Cucumber test suites
check_circleGenerating CircleCI / GitLab CI YAML from a CSV pipeline plan
check_circleMigrating product catalogues into YAML data layers for headless CMSes

Block YAML vs flow YAML — why block wins

YAML supports two syntaxes for the same data: block style (indentation-based, one key per line) and flow style ({key: value} JSON-like). Both are valid, but every real-world YAML config — Kubernetes, Ansible, Helm, GitHub Actions — uses block style because it is reviewable in pull requests, diff-friendly, and easy to scan. The OpenFormatter converter always emits block style. If you need flow style, the YAML output is also valid input to YAML Formatter which can switch styles.

Need a different output format?

Convert the same CSV to JSON for APIs, XML for EDI, or a styled HTML table for the web.

CSV to JSON CSV to XML YAML Formatter

Frequently Asked Questions

Will the YAML use block or flow style?

Block style — the human-readable form with one key per line and indentation indicating nesting. Flow style (the JSON-like {key: value} form) is technically valid YAML but defeats the readability advantage; block style is what Ansible, Kubernetes manifests, GitHub Actions, and most YAML files use in practice.

What happens if a header contains spaces or hyphens like "First Name"?

Header names are sanitised: spaces and hyphens are replaced with underscores so the resulting YAML key is a clean identifier (first_name). Leading non-letters are also prefixed with an underscore. This avoids the need to quote keys and matches common Ansible / Kubernetes naming conventions.

How are values quoted in the output?

The converter quotes values only when YAML would otherwise misinterpret them — values containing colons, hashes, brackets, leading whitespace, or starting with reserved characters get JSON-style double quotes. Simple text, numbers, and booleans are emitted unquoted, keeping the output as readable as a hand-written file.

Are numbers, booleans, and null typed correctly?

Yes. A value matching an integer or float is emitted unquoted, so the YAML parser reads it as a number. The literal true and false stay as YAML booleans, and null or ~ becomes YAML null. This matches what Ansible, Helm, and Kubernetes parsers expect.

Is the output Ansible / Kubernetes / Helm compatible?

Yes. The output is a YAML 1.2 sequence of mappings — directly usable as an Ansible vars file, a Kubernetes ConfigMap data field, or a Helm values.yaml fragment. Drop the result under a top-level key in your existing manifest and reference it from your playbook or templates.

Why does YAML treat "yes" or "off" as booleans in some parsers?

Older YAML 1.1 parsers (still used by some Ansible code paths) treat yes, no, on, off as booleans — the famous Norway problem where the country code NO became false. Modern YAML 1.2 only accepts true/false. To be safe, quote ambiguous strings; this converter quotes anything containing reserved characters by default.

Does the tool upload my CSV anywhere?

No. Conversion is JavaScript running in your browser. Server inventories, secrets, and configuration data never leave the device. Open the Network tab and confirm — there are no requests when you press Convert.

How do I wrap the output under a top-level key for Ansible?

After converting, prefix every output line with two spaces and add a top-level key on its own line — e.g. servers: followed by the indented list. Most editors do this with a Tab on a multi-line selection. The OpenFormatter YAML Formatter can also re-indent the result if you nest it manually.