How to Manage Multiple GitHub Accounts on One Machine

Managing multiple GitHub accounts (such as a personal account and a work account) on a single machine can be tricky. If you don’t configure it correctly, you’ll constantly run into permission errors.

The most robust way to handle this is by using SSH keys and a custom SSH configuration file. Here is a step-by-step guide to setting it up seamlessly.

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Step 1: Generate Separate SSH Keys

First, open your terminal and generate unique SSH keys for both your personal and work accounts.

1. Generate Personal SSH Key

ssh-keygen -t ed25519 -C "personal@email.com" -f ~/.ssh/id_ed25519_personal

When prompted for a passphrase, press Enter twice to leave it empty.

Your terminal will confirm that your keys have been saved:

Your identification has been saved in /Users/userName/.ssh/id_ed25519_personal
Your public key has been saved in /Users/userName/.ssh/id_ed25519_personal.pub

2. Copy the Personal Key to GitHub

View your public key using the cat command:

cat ~/.ssh/id_ed25519_personal.pub

Copy the output (which starts with ssh-ed25519...), then log into your personal GitHub account. Go to Settings > SSH and GPG keys > New SSH Key, paste the key, and save it.

3. Generate Work SSH Key

Repeat the same process for your professional/work account:

ssh-keygen -t ed25519 -C "orgemail@work.com" -f ~/.ssh/id_ed25519_work

Copy this public key (cat ~/.ssh/id_ed25519_work.pub) and add it to your work GitHub organization account.

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Step 2: Create a Custom SSH Configuration

To tell your machine which SSH key to use for each account, you need to create or edit your SSH config file.

Open or create ~/.ssh/config:

nano ~/.ssh/config

Add the following configuration layout. Notice how we use unique aliases for the Host lines to separate the accounts:

# Personal GitHub
Host github.com-personal
  HostName github.com
  User git
  PreferredAuthentications publickey
  IdentityFile ~/.ssh/id_ed25519_personal

# Work GitHub
Host github.com-work
  HostName github.com
  User git
  PreferredAuthentications publickey
  IdentityFile ~/.ssh/id_ed25519_work

Save and exit the editor (in Nano, press Ctrl+O, Enter, then Ctrl+X).

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Step 3: Test the Connections

Before interacting with your repositories, verify that your machine successfully authenticates with GitHub using the custom hosts.

Test your personal connection:

ssh -T git@github.com-personal

The first time you connect, you will see a security warning:

The authenticity of host 'github.com (20.xxx.xx.xx)' can't be established.
ED25519 key fingerprint is SHA256:+................xxxxx........
Are you sure you want to continue connecting (yes/no/[fingerprint])?

Type yes and hit Enter. You should get a successful response matching your personal username:

Hi username! You've successfully authenticated, but GitHub does not provide shell access.

Test your work profile using the exact same step:

ssh -T git@github.com-work

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Step 4: How to Use Your Repositories

Now that the routing rules are established, you need to slightly tweak how you clone and configure your local git projects.

Case A: Cloning a New Repository

When cloning via SSH, replace github.com in the clone URL with the custom Host alias you defined in your config file.

For a Personal Repo:

# Original URL: git@github.com:personal-user/repo.git
git clone git@github.com-personal:personal-user/repo.git

Example - 
git clone git@github.com-personal:sunilpatro1985/Playwright-TS-BoilerPlate-Framework.git

For a Work Repo:

# Original URL: git@github.com:work-org/repo.git
git clone git@github.com-work:work-org/repo.git

Case B: Updating an Existing Locally Cloned Repository

If you have already cloned a repository prior to setting up multiple accounts, update its remote URL to route through the new alias config:

git remote set-url origin git@github.com-personal:personal-user/repo.git

Don’t Forget: Configure Local Author Information

To prevent committing to your work repository with your personal email (or vice-versa), always set local configurations inside each repository directory instead of using git config --global.

Navigate into your specific project folder and execute:

git config user.name "Your Name"
git config user.email "personal@email.com" # Or orgemail@work.com for work projects