JSON and YAML for configuration files: reading, editing and fixing them
For IT technicians, system administrators, junior developers and DevOps staff who open configuration files to change a setting: editor settings, Docker Compose files, Kubernetes manifests and CI workflows. No programming is needed, only a plain-text editor and a terminal. You'll learn JSON's strict rules from RFC 8259, how YAML uses indentation and how its parser decides whether a value is a number, a boolean or a string (from the YAML 1.2.2 specification), how to read a parser's error message and validate before you save, and which format each common tool expects. Your organization's change process decides who may change production configuration and where secrets are kept.
- Level
- Beginner
- Length
- About 95 minutes
- Contents
- 5 lessons · final exam
- Status
- Published · updated 10 Oct 2026
Skills you'll practise
- Identify JSON value types and the syntax rules RFC 8259 sets for names, literals, numbers, commas and comments
- Read YAML structure: block mappings, sequences, indentation and multi-line strings
- Predict how a YAML parser will type a value and quote values that must stay strings
- Find and fix syntax errors in JSON and YAML files using the parser's error message and a validator
- Choose the right format and conventions for a tool: strict JSON, JSON with Comments or YAML
Course outline
- 1.JSON value types and the syntax rules RFC 8259 setsLesson · 15 min
- 2.Reading YAML structure: block mappings, sequences, indentation and multi-line stringsLesson · 18 min
- 3.Predicting how a YAML parser types a value, and quoting values that must stay stringsLesson · 16 min
- 4.Finding and fixing syntax errors using the parser's error message and a validatorLesson · 16 min
- 5.Choosing the right format for a tool: strict JSON, JSON with Comments or YAMLLesson · 12 min
- 6.JSON and YAML for configuration files: reading, editing and fixing them: knowledge checkKnowledge check · 14 questions
- 7.JSON and YAML for configuration files: reading, editing and fixing them: practical exerciseKnowledge check · 1 question
- 8.Final exam10 questions · passing it completes the course, so people who already know the material can test out
Sources it draws on
The lessons and questions are written from these references, so learners can go back to the original.
- IETF RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format (December 2017)
- YAML Ain't Markup Language (YAML) revision 1.2.2 (October 2021)
- YAML 1.1 Boolean Language-Independent Type (working draft, 2005)
- Python documentation: json, JSON encoder and decoder (command-line interface, repeated names)
- Visual Studio Code documentation: Editing JSON with Visual Studio Code (JSON with Comments)
- Kubernetes documentation: Objects in Kubernetes (manifests in YAML or JSON)
- GitHub Docs: Workflow syntax for GitHub Actions
- Docker Docs: Compose file reference, Fragments (anchors, aliases and merge keys)
- Docker Docs: docker compose config (CLI reference)
See it with your own jobs and topics
Tell us about your team and we'll walk you through setup, from choosing jobs to your first skills check.