YAML Config and API Patterns

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Application config, OpenAPI, environment settings, and interoperability patterns for YAML across modern tooling.

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App config patterns

Reusable YAML examples for application settings, feature flags, and environment config.

App config example

Structure app settings in a readable YAML document.

yamlANYyamlconfigapplication

↗#

yaml

app:
  name: Cheatsheet.today
  env: production
  features:
    ai_search: true
    premium_packs: true
  database:
    host: localhost
    port: 5432

Notes

A common YAML layout for application config files and internal tools.

Environment-specific config

Model different settings by environment.

yamlANYyamlconfigenvironment

↗#

yaml

environments:
  development:
    log_level: debug
  production:
    log_level: info

Notes

Keeping environments in one structure can simplify smaller projects and documentation.

OpenAPI YAML snippet

Show how YAML appears in API documentation.

yamlANYyamlopenapiapi

↗#

yaml

openapi: 3.1.0
info:
  title: ExpressYou API
  version: 1.0.0
paths: {}

Notes

OpenAPI is a major YAML use case and an SEO-friendly adjacent topic.

Validate an OpenAPI YAML file

Check API spec correctness from the command line.

bashANYyamlopenapivalidation

↗#

bash

swagger-cli validate openapi.yaml

Notes

Useful when YAML is being used as an API contract rather than plain config.

Conversion and interoperability

Move YAML data between formats and systems safely.

Convert JSON to YAML with Python

Transform JSON into YAML output for config workflows.

bashANYyamljsonconversionpython

↗#

bash

python - <<'PY'
import json, yaml, sys
print(yaml.safe_dump(json.load(open('config.json')), sort_keys=False))
PY

Notes

Helpful when migrating configs or producing more human-readable output.

Convert JSON to YAML with yq

Convert JSON input into YAML from the shell.

bashANYyamljsonyq

↗#

bash

yq -P -p=json '.' config.json

Notes

Useful in scripts and format conversion pipelines.

Convert Compose to resolved output

Render final service configuration from a YAML Compose file.

bashANYyamlcomposeconversion

↗#

bash

docker compose convert

Notes

Useful for troubleshooting generated or inherited Compose config.

Build layered Kubernetes YAML

Generate final Kubernetes YAML from base and overlays.

bashANYyamlkustomizekubernetes

↗#

bash

kustomize build overlays/prod

Notes

A practical YAML workflow for teams using declarative deployment overlays.

More in YAML

YAML Validation, Linting, and Troubleshooting

Common syntax errors, duplicate keys, parser checks, and validation workflows for debugging YAML faster.

YAML with yq: Query, Edit, and Transform

High-value yq commands for reading, updating, filtering, converting, and merging YAML in local scripts and CI pipelines.

YAML for DevOps, Kubernetes, and CI

Kubernetes manifests, GitHub Actions, Helm, Compose, and YAML-powered automation workflows with practical validation commands.

YAML Multi-Document Streams

Document separators, multi-resource YAML files, and commands for splitting, filtering, and validating streamed YAML.

YAML Anchors, Aliases, and Merge Keys

Reusable YAML patterns using anchors and aliases, with merge examples and commands for expanding and validating resolved config.

YAML Indentation and Structure

Indentation patterns, nested lists and maps, and practical commands for catching whitespace and structure mistakes.

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