Convert JSON to a Helm Chart values.yaml

A typical chart config object converts to a clean values.yaml. Note image.tag is quoted as a string so 1.25 doesn't become the float 1.25.

JSON:
{"replicaCount":3,
 "image":{"repository":"myreg/web","tag":"1.25"},
 "service":{"type":"ClusterIP","port":80},
 "ingress":{"enabled":true}}

YAML (indent 2):
replicaCount: 3
image:
  repository: myreg/web
  tag: '1.25'
service:
  type: ClusterIP
  port: 80
ingress:
  enabled: true

Many charts' values.schema.json require a string port. The converter follows JSON types exactly — so you must make the port a string in the JSON. It will NOT quote a number for you.

Chart wants a STRING port.

Wrong JSON (number): {"service":{"port":8080}}
→ YAML: port: 8080        # integer — schema validation fails

Right JSON (string): {"service":{"port":"8080"}}
→ YAML: port: '8080'      # string — passes the chart schema

Arrays of maps become compact YAML sequences at indent 2 — the form Helm charts expect for extraEnv, tolerations, and imagePullSecrets.

JSON:
{"extraEnv":[{"name":"LOG_LEVEL","value":"info"}],
 "imagePullSecrets":[{"name":"regcred"}]}

YAML (indent 2):
extraEnv:
  - name: LOG_LEVEL
    value: info
imagePullSecrets:
  - name: regcred

JSON has no comments, so the output has none. Add # annotations by hand in your editor — the main ergonomic reason to keep values in YAML.

JSON: {"resources":{"limits":{"cpu":"500m","memory":"512Mi"}}}

YAML (as produced — no comments):
resources:
  limits:
    cpu: 500m
    memory: 512Mi

After hand-editing:
resources:
  limits:
    cpu: 500m       # bumped from 250m for the v2 release
    memory: 512Mi

To roll a base config plus an environment override into one values file, merge the JSON first with json-object-merger, then convert. Or keep them separate and pass multiple --values flags to Helm.

base.json + prod.json
   → json-object-merger (deep merge, prod wins)
   → json-to-yaml (indent 2)
   → values-prod.yaml

Alternatively, skip the merge and let Helm layer them:
helm upgrade web ./chart -f values.yaml -f values-prod.yaml

JSON cannot contain comments, so there is nothing for the converter to carry over, and it adds none of its own. The output values.yaml has no # annotations. Add documentation comments by hand after conversion — this is the main readability reason to keep Helm values in YAML rather than JSON.

The converter follows JSON types exactly — it will not quote a number into a string. If your chart's values.schema.json requires a string port or version and your JSON has a number, validation fails on helm upgrade. Fix the type in the JSON ("8080") before converting.

If a version is stored as a JSON number like 1.10, JSON.parse reads it as 1.1 (trailing zero dropped) before YAML sees it. Always store chart/image tags and versions as JSON strings ("1.10") so they survive as '1.10'.

At indent 4, each extraEnv/tolerations/imagePullSecrets item is written as a bare - with the map indented beneath. Helm parses it, but it doesn't match chart conventions and may trip linters. Use indent 2.

JSON null becomes literal null. Many charts treat a null value differently from an omitted key (an omitted key falls through to the chart default; an explicit null may override it). Review null lines and strip ones you'd rather leave to defaults, or pre-clean with json-null-stripper.

The converter runs JSON.parse on the file. A trailing comma or comment throws and nothing converts. Terraform/CI output is usually strict JSON, but if you hand-edited it, fix it with json-format-fixer first.

Numbers above 2^53 are rounded by JSON.parse before conversion. Uncommon in Helm values, but if a config carries a giant numeric ID, store it as a JSON string to keep it intact.

If the source JSON has the same key twice in one object, only the last survives JSON.parse — the first is silently dropped before conversion. Validate hand-merged configs with json-validator.

Repeated maps (e.g. the same resource block reused across two components) are written out in full — anchor generation is disabled (noRefs fixed on). Helm supports anchors, but writing blocks out keeps helm template rendering predictable and the file readable.

An empty object becomes {} and an empty array [] on one line. A chart section you intend to leave at its defaults is often better omitted entirely than written as section: {} — delete it after conversion if so.