GitHub Actions workflow basics

iinventedlight (synthesis of cited sources); text drafted with AI assistance

GitHub Actions workflow basics

Short answer

GitHub Actions is GitHub's CI/CD platform. A workflow is a YAML file in .github/workflows/ that runs one or more jobs when an event (push, pull request, schedule, issue opened...) triggers it. Jobs run on GitHub-hosted Linux, Windows or macOS machines or on your own runners. [S1][S2]

name: CI
on: [push, pull_request]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm test

Key points

Files need a .yml or .yaml extension. [S2]
One repository can have many workflows; workflows can reuse others. [S1]

Claims

id: C1 claim: GitHub Actions is a CI/CD platform. source: S1 evidence: "GitHub Actions is a continuous integration and continuous delivery (CI/CD) platform"
id: C2 claim: Workflows are defined in .github/workflows. source: S1 evidence: "Workflows are defined in the .github/workflows directory in a repository."
id: C3 claim: Workflow files must have a .yml or .yaml extension. source: S2 evidence: "must have either a .yml or .yaml file extension"
id: C4 claim: Use on to define which events trigger a workflow. source: S2 evidence: "use on to define which events can cause the workflow to run"

Sources

[S1] Understanding GitHub Actions - GitHub Docs. GitHub Docs. https://docs.github.com/en/actions/about-github-actions/understanding-github-actions . License: CC BY 4.0 (github/docs). Accessed 2026-11-04.
[S2] Workflow syntax for GitHub Actions - GitHub Docs. GitHub Docs. https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions . License: CC BY 4.0 (github/docs). Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

License: CC-BY-4.0 · Summary by iinventedlight (AI-assisted). Sources: GitHub Docs, Understanding GitHub Actions - GitHub Docs, CC BY 4.0 (github/docs); GitHub Docs, Workflow syntax for GitHub Actions - GitHub Docs, CC BY 4.0 (github/docs).

Cite this

Permanent ID: iil:note:3y32kf9g

iinventedlight. 2026. "GitHub Actions workflow basics." iinventedlight Library, iil:note:3y32kf9g, version of 2026-11-04. https://iinventedlight.com/library/notes/github-actions-workflow-basics/. License: CC-BY-4.0.

@misc{iil_note_3y32kf9g,
  author = {{iinventedlight}},
  title = {{GitHub Actions workflow basics}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-04},
  url = {https://iinventedlight.com/library/notes/github-actions-workflow-basics/},
  note = {Permanent ID iil:note:3y32kf9g. License: CC-BY-4.0.},
}

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