Pipeline variables

What it is

Pipeline variables are named, typed values that you inject into a CI job/stage at runtime — rather than hard-coding a value into the pipeline YAML or the script. Azure Pipelines scopes them (pipeline, runtime, project) with $(var) syntax; GitHub Actions maps them via env:/with: and ${{ }}.

Why it exists

To make one pipeline definition reusable across environments (dev/test/prod), branches, and compilations without editing the YAML itself. Variables turn a fixed script into a parameterized, env-aware performer — the same logic, different inputs.

Key ideas

• Scope/precedence: runtime (inline/API) > pipeline/subscription > project/env, mirroring how env: in GitHub builds on the workflow+dependency store.
• Typing: string, bool, secret, number; YAML variables: defaults + secrets. store references.
• Secrets are variables with extra protection: masked in logs, never echoed; GitHub ${{ secrets.X }}, Azure secretParameters.
• Consumption is via expression syntax at build time $(VAR) in Azure Pipelines and ${{ env.VAR }} in GitHub Actions.

How it fits (diagram)

Exam notes

• Variables are resolved at runtime; secrets are a masked subset — do not print them.
• Precedence and scoping rules are frequent questions (same name = which wins).
• GitHub env: at workflow/job vs with: to an action — know which scope applies where.

Related

pipeline-run · azure-pipelines · github-actions · advanced-yaml-pipelines

📘 Source: Azure Pipelines variables · YAML expressions