YAML to JSON Converter

YAML (YAML Ain't Markup Language) is a human-readable data serialization format popular in DevOps, CI/CD pipelines, and configuration files. Kubernetes manifests, GitHub Actions workflows, Docker Compose files, and Ansible playbooks all use YAML. YAML supports features JSON does not: comments, multi-line strings, anchors and aliases for reusing data, and implicit typing (e.g., "yes" becomes boolean true). JSON is stricter, more compact, and universally parseable by every programming language. Converting YAML to JSON is useful when you need to feed config data into a tool or API that only accepts JSON, or when you want to programmatically manipulate the data with jq or a JSON library.

This tool uses js-yaml, a JavaScript library that parses YAML 1.1 and YAML 1.2 documents (the versions commonly used in Kubernetes and GitHub Actions). For YAML→JSON, the tool parses your YAML input and serializes the resulting JavaScript object as pretty-printed JSON. For JSON→YAML, it parses your JSON and dumps it as indented YAML with readable formatting. All conversion happens in your browser - no configuration data is uploaded to a server. This is important for security-sensitive configs that may contain API keys, database passwords, or internal hostnames.

YAML anchors and aliases (&label and *label) let you define a block once and reuse it elsewhere in the document. When you convert YAML with anchors to JSON, the alias references are expanded into full copies. For example, a YAML Kubernetes deployment with &commonLabels reused in multiple places will have those labels duplicated in each location in the JSON output. The structure is correct, but the DRY (don't repeat yourself) benefit of anchors is lost. Custom YAML tags (like !!str or !!int) are parsed by js-yaml based on the YAML 1.1 type system; most common tags work, but exotic custom tags may not convert cleanly.

YAML allows comments (lines starting with #), but JSON has no comment syntax. When you convert YAML to JSON, all comments are discarded. This is a permanent loss - converting the JSON back to YAML will not restore the original comments. If you need to preserve comments for documentation purposes, keep the original YAML file and only convert a copy to JSON. YAML also supports multi-line strings with | (literal) and > (folded) block scalars; these are converted to JSON strings with embedded newlines (\n), which is correct but harder to read in JSON.

Worked example: A DevOps engineer has a Kubernetes ConfigMap in YAML format with environment variables for a microservice. The engineer needs to test the config by POSTing it to a custom API that only accepts JSON. Converting the YAML to JSON produces a valid JSON object: {"apiVersion":"v1","kind":"ConfigMap","metadata":{"name":"app-config"},"data":{"DB_HOST":"postgres.internal","DB_PORT":"5432"}}. The engineer copies the JSON and sends it to the API with curl -X POST -H "Content-Type: application/json" -d @config.json. The conversion was done locally in the browser, so internal hostnames and config values never left the engineer's laptop.