# Flow of CI Pipeline

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1769397512469/af84e3fb-8fd2-43fe-9940-3e72dc827a44.png align="center")

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## 1\. Code Commit (Starting Point)

The CI pipeline starts when a **developer writes code** and pushes it to a **version control system** like Git.

What happens:

* Developer makes changes
    
* Runs basic checks locally
    
* Pushes code to Git repository (GitHub / GitLab / Bitbucket)
    

Why this matters:

* CI ensures every code change is tested automatically
    
* No waiting for manual builds
    

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## 2\. Trigger the CI Pipeline

Once code is pushed, the CI tool (like Jenkins) detects the change.

How it triggers:

* Webhook from Git
    
* Poll SCM (not recommended)
    
* Manual trigger (for testing)
    

Result:

* A new CI job starts automatically
    

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## 3\. Source Code Checkout

The pipeline pulls the **latest code** from the repository.

Actions:

* Clones the repo
    
* Checks out the correct branch (main, develop, feature branch)
    

Why:

* CI always works on fresh code
    
* Avoids local machine dependency
    

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## 4\. Environment Setup

Before building, the pipeline prepares the environment.

Includes:

* Installing dependencies
    
* Setting up language runtime (Java, Node, Python)
    
* Loading environment variables
    
* Injecting credentials securely
    

Example:

* Node modules install
    
* Maven dependencies download
    

Purpose:

* Makes builds repeatable and consistent
    

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## 5\. Build Stage

Now the actual build happens.

Examples:

* Java: `mvn clean package`
    
* React: `npm run build`
    
* Python: create package or artifact
    

Output:

* Build artifacts (JAR, WAR, ZIP, dist folder)
    

Why:

* Converts source code into deployable format
    

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## 6\. Automated Testing

This is the core of CI.

Types of tests:

* Unit tests
    
* Integration tests
    
* Basic smoke tests
    

What happens:

* Tests run automatically
    
* Pipeline stops if any test fails
    

Why:

* Catches bugs early
    
* Prevents broken code from moving forward
    

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## 7\. Code Quality & Security Checks (Optional but Strong)

Many teams add quality gates.

Includes:

* Static code analysis
    
* Code coverage checks
    
* Security scans
    

Tools:

* SonarQube
    
* ESLint
    
* Snyk
    

Purpose:

* Maintains code standards
    
* Reduces technical debt
    

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## 8\. Artifact Versioning & Storage

After a successful build:

* Artifacts are versioned using build number or commit ID
    
* Stored in artifact repositories
    

Examples:

* Nexus
    
* Artifactory
    
* S3
    

Why:

* Traceability
    
* Rollback support
    

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## 9\. Notifications

The pipeline sends build status to the team.

Examples:

* Slack message
    
* Email
    
* Git status update
    

Purpose:

* Immediate feedback
    
* Team visibility
    

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## 10\. CI Pipeline End

At this point:

* Code is built
    
* Tested
    
* Verified
    

If all stages pass:

* CI pipeline succeeds
    
* Code is ready for CD (deployment)
    

If any stage fails:

* Pipeline stops
    
* Developer fixes the issue and pushes again
    

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## CI Pipeline Flow in One Line

> Code Commit → Trigger → Checkout → Setup → Build → Test → Quality Check → Artifact Store → Notify

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## CI vs CD (Quick clarity)

* **CI** stops at build + test
    
* **CD** continues with deployment to staging or production
    

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## Interview-Ready Summary

> A CI pipeline automates code integration by building, testing, and validating every code change, ensuring fast feedback, high code quality, and stable software delivery