How to Automate Sync from Bitbucket to GitHub Using Bitbucket Pipelines

Prasanta Mondal — Fri, 22 Aug 2025 00:44:26 +0000

This guide walks you through setting up automated syncing from a private Bitbucket repository to GitHub using Bitbucket Pipelines, helping you leverage GitHub's generous CI/CD minutes while keeping Bitbucket as your primary development hub.

Overview

Here's why I have made the sync :
Bitbucket offers only 50 free pipeline minutes, while GitHub provides 2000 minutes - a significant difference for CI/CD workflows. Bitbucket remains my primary repository where all development happens. Only sync the main branch and git tags to create a broad deployment pipeline from Git.

How It Works

You push code or create tags in Bitbucket → Bitbucket Pipelines automatically triggers → Only new commits on main branch and new tags get pushed to GitHub → Then you can do anything with Github actions later.

Prerequisites

Before starting, ensure you have:

Administrative access to both repositories (Bitbucket source and GitHub target)
Private repositories on both Bitbucket and GitHub
Git installed locally for initial full mirror setup
SSH key authentication already set up for your local machine (skip if already configured)

Optional: SSH Authentication Setup (Skip if Already Configured)

If you haven't set up SSH authentication with GitHub and Bitbucket, follow these steps:

Generate SSH Key Pair

ssh-keygen -t ed25519 -C "actual_email@example.com"

Add SSH Key to SSH Agent

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

Copy Public Key to Clipboard

cat ~/.ssh/id_ed25519.pub

Add to GitHub and Bitbucket

GitHub: Settings (user) → SSH and GPG keys → New SSH key → Paste your key
Bitbucket: Personal settings → SSH keys → Add key → Paste your key

Test SSH Connection

ssh -T git@github.com
ssh -T git@bitbucket.org

Configure Git

git config --global user.name "Your Name"
git config --global user.email "your_email@example.com"

Step-by-Step Mirror and Sync Setup

Step 1: Create GitHub Repository

Go to GitHub and create a new private repository.
Important: Do not initialize with README, .gitignore, or license
Note your GitHub repository URL: git@github.com:username/repository-name.git

Step 2: Enable Bitbucket Pipelines

In your Bitbucket repository, go to Repository Settings
Navigate to Pipelines → Settings
Enable Pipelines by toggling the switch

Step 3: Generate SSH Keys in Bitbucket

Go to Repository Settings → Pipelines → SSH keys
Click Generate keys then
Copy the public key to your clipboard
most of the time system detects known host so don't need to add.

Step 4: Configure GitHub Deploy Key

Go to your GitHub repository
Navigate to Settings → Deploy keys
Click Add deploy key
Paste the Bitbucket public key
Check "Allow write access"
Click Add key

Step 5: Configure Bitbucket Access Key

Return to Bitbucket Repository Settings → Security → Access keys
Click Add key
Paste the same public key you used for GitHub
This allows Bitbucket to authenticate with your repository

Step 6: Initial Full Mirror (One-Time Setup)

Run this command on your local machine to sync past commits:

# Clone the Bitbucket repository
git clone --mirror git@bitbucket.org:your-workspace/your-repo.git

# Navigate to the repository
cd your-repo.git

# Add GitHub as a remote
git remote add github git@github.com:your-username/your-github-repo.git

# Push everything to GitHub (one-time full sync)
git push --mirror github

Why do this locally? If you add logic of mirror in pipelines than that will runs all the time , which is resource and time taking, instead for once locally in a temporary folder we can mirror that, once successful then we can delete the local folder.

Step 7: Create Pipeline Configuration

Create a bitbucket-pipelines.yml file in your Bitbucket repository root, or locally & push that . Choose one of these two options (I recommend Option A for simplicity):

Option A: Using Bitbucket Built-in SSH Key (Recommended)

image: atlassian/default-image:3

pipelines:
  branches:
    main:
      - step:
          name: Sync main branch to GitHub
          image: alpine/git:latest
          clone:
            enabled: false
          script:
            - git clone --branch=main --single-branch git@bitbucket.org:your-workspace/your-repo.git
            - cd your-repo
            - git remote add github git@github.com:your-username/your-github-repo.git
            - git push github main

  tags:
    '*':
      - step:
          name: Sync new tag to GitHub
          image: alpine/git:latest
          clone:
            enabled: false
          script:
            - git clone --branch=main --single-branch git@bitbucket.org:your-workspace/your-repo.git
            - cd your-repo
            - git remote add github git@github.com:your-username/your-github-repo.git
            - git push github $BITBUCKET_TAG

Option B: Using Custom SSH Key (Advanced)

If you prefer using your own SSH key:

Generate a custom SSH key pair locally:

ssh-keygen -t ed25519 -C "bitbucket-pipeline" -f bitbucket_pipeline_key

Encode the private key:

base64 -w 0 < bitbucket_pipeline_key

Add the public key to GitHub deploy keys (with write access)
Add the base64-encoded private key as a secured variable in Bitbucket:
- Go to Repository Settings → Pipelines → Repository variables
- Create variable GITHUB_SSH_KEY with the base64 value
- Check "Secured"
Use this pipeline configuration:

image: atlassian/default-image:3

pipelines:
  branches:
    main:
      - step:
          name: Sync main → GitHub
          image: alpine/git:latest
          clone:
            enabled: false
          script:
            - apk add --no-cache openssh-client
            - mkdir -p ~/.ssh
            - echo "$GITHUB_SSH_KEY" | base64 -d > ~/.ssh/id_ed25519
            - chmod 600 ~/.ssh/id_ed25519
            - ssh-keyscan -H github.com >> ~/.ssh/known_hosts
            - git clone --branch=main --single-branch git@bitbucket.org:your-workspace/your-repo.git
            - cd your-repo
            - git remote add github git@github.com:your-username/your-github-repo.git
            - GIT_SSH_COMMAND='ssh -i ~/.ssh/id_ed25519' git push github main

  tags:
    '*':
      - step:
          name: Sync new tag → GitHub
          image: alpine/git:latest
          clone:
            enabled: false
          script:
            - apk add --no-cache openssh-client
            - mkdir -p ~/.ssh
            - echo "$GITHUB_SSH_KEY" | base64 -d > ~/.ssh/id_ed25519
            - chmod 600 ~/.ssh/id_ed25519
            - ssh-keyscan -H github.com >> ~/.ssh/known_hosts
            - git clone --branch=main --single-branch git@bitbucket.org:your-workspace/your-repo.git
            - cd your-repo
            - git remote add github git@github.com:your-username/your-github-repo.git
            - GIT_SSH_COMMAND='ssh -i ~/.ssh/id_ed25519' git push github $BITBUCKET_TAG

Step 8: Commit Pipeline Configuration

Add the bitbucket-pipelines.yml file to your repository
Commit and push to Bitbucket
The pipeline should trigger automatically

Test :

Push a Commit to Main Branch:
```
git add .
git commit -m "Test sync to GitHub"
git push origin main
```
- For tags
```
git tag v1.0.0
git push origin v1.0.0
```
Check the pipeline execution in your Bitbucket repository under Pipelines section.

Notes:

--single-branch reduces data transfer
clone: enabled: false prevents unnecessary default cloning
Avoid --mirror in pipelines (use only for initial setup)

Summary

This setup creates an efficient, automated sync between Bitbucket and GitHub that:

Keeps Bitbucket as your source of truth
Syncs only main branch (or you can do for any branch or whole repo ) and tags
Maintains security through SSH key authentication

The pipeline runs automatically whenever you push to main or create tags, ensuring your GitHub repository stays synchronized without manual intervention.

DEV Community: Prasanta Mondal