Convert Kubernetes YAML to JSON

The base case: one resource, multi-doc toggle off, 2-space indent. apiVersion, kind, metadata, and spec land at the top level exactly as the API expects.

Input (deployment.yaml):
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web
  labels:
    app: web
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web

Output JSON (2-space):
{
  "apiVersion": "apps/v1",
  "kind": "Deployment",
  "metadata": { "name": "web", "labels": { "app": "web" } },
  "spec": { "replicas": 3, "selector": { "matchLabels": { "app": "web" } } }
}

A real kubectl apply -f file with two documents. Toggle off, this throws. Toggle ON, you get a two-element array — one object per document.

Input (stack.yaml):
apiVersion: apps/v1
kind: Deployment
metadata: { name: web }
---
apiVersion: v1
kind: Service
metadata: { name: web-svc }

Multi-document YAML (---): ON

Output JSON:
[
  { "apiVersion": "apps/v1", "kind": "Deployment", "metadata": { "name": "web" } },
  { "apiVersion": "v1", "kind": "Service", "metadata": { "name": "web-svc" } }
]

The most common support question for this tool. The fix is one checkbox, not a different file.

Input: a 3-resource manifest with two `---` separators
Multi-document YAML (---): OFF

Error shown in the red panel:
  expected a single document in the stream, but found more

Fix: turn the Multi-document YAML (---) checkbox on, re-run.

Two coercion traps in one manifest. Quote what must be text; expect numeric trimming on what you leave unquoted.

Input:
spec:
  nodePort: "30080"
  minorVersion: 1.10

Output JSON:
{
  "spec": {
    "nodePort": "30080",   // quoted → string preserved
    "minorVersion": 1.1     // unquoted 1.10 → 1.1
  }
}

Hand-written manifests sometimes share a resources block via an anchor. The converter dereferences it — the JSON has no anchors left, just the expanded values.

Input:
resources: &res
  limits: { cpu: "500m", memory: 256Mi }
containerA:
  resources:
    <<: *res
    requests: { cpu: "100m" }

Output JSON (anchor resolved):
{
  "resources": { "limits": { "cpu": "500m", "memory": "256Mi" } },
  "containerA": { "resources": {
    "limits": { "cpu": "500m", "memory": "256Mi" },
    "requests": { "cpu": "100m" }
  } }
}

With Multi-document YAML (---) off, the parser calls yaml.load, which is strict about one document per stream and throws expected a single document in the stream, but found more at the first extra ---. This is not a malformed-file problem — turn the toggle on and re-run.

A file ending in --- followed by nothing parses (with the toggle on) into an array whose final element is null. Harmless for inspection, but if you iterate the array to apply each resource, skip null elements. Remove the trailing separator in the source to avoid it.

Plain Kubernetes manifests have no custom tags, but if a value is annotated with an explicit unknown tag (!Custom, !Ref copied from CloudFormation, etc.) js-yaml throws unknown tag. The default schema only knows standard YAML 1.2 tags. Remove or quote the tagged value.

YAML forbids tabs in indentation. A tab where spaces are expected throws tab characters must not be used in indentation, with line and column. Re-indent with spaces — most editors can convert tabs to spaces for .yaml files automatically.

Two metadata: blocks (or any repeated key) in the same mapping throw duplicated mapping key with the offending line. js-yaml rejects rather than silently keeping the last value — fix the manifest so each key appears once.

An empty file (or one with only comments) parses to JS undefined, and the output is literally undefined rather than {} or null. Paste actual resource content. With the multi-doc toggle on, a single empty doc yields null.

Leading-zero integers like a containerPort: 08 are parsed as decimal 8 (js-yaml does not treat them as octal in the core schema). The value is numerically correct for k8s but the textual form changes — quote it if a literal "08" matters.

Unlike YAML 1.1 tools, js-yaml 4.x keeps yes/no/on/off as strings (no Norway problem), so a region: no stays "no" — not a boolean. If you actually want a boolean, write true/false.

Integers beyond JavaScript's safe range (2^53−1) lose precision through the JS number type — 9999999999999999999 round-trips as 10000000000000000000. Rare in k8s specs, but if you embed huge IDs, quote them so they stay exact strings.

Free tier caps JSON-family input at 2 MB and one file at a time — plenty for normal manifests. A monster generated manifest bundle over 2 MB needs Pro (100 MB). Or split the bundle and convert each resource separately.