How to setup multiple github account ssh config

If you use both a personal and a work GitHub account, you’ve likely run into issues like commits using the wrong email or pushes failing due to incorrect SSH keys.

The Problem

GitHub associates each SSH key with a single account. That means:

• One key = one account
• Multiple accounts = multiple SSH keys

You also need to ensure commits use the correct user.name and user.email based on the project.

Overview

Here’s what we are going to setup:

1. Generate an SSH Key per Github account.
2. Add each public key to the corresponding Github account.
3. Configure ~/.ssh/config file with host aliases.
4. Configure git to auto-switch identity based on repository directory

Below are two example accounts:

Step 1: Generate SSH Keys

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# Personal account
ssh-keygen -t ed25519 -C "simon@personal.dev" -f ~/.ssh/id_ed25519_personal

# Work account
ssh-keygen -t ed25519 -C "simon@work.com" -f ~/.ssh/id_ed25519_work

After this the output structure would like:

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~/.ssh/
├── id_ed25519_personal       # private key (personal)
├── id_ed25519_personal.pub   # public key (personal)
├── id_ed25519_work            # private key (work)
└── id_ed25519_work.pub        # public key (work)

Step 2: Add Keys to the SSH Agent

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# Start the agent
eval "$(ssh-agent -s)"

# Add both keys
ssh-add ~/.ssh/id_ed25519_personal
ssh-add ~/.ssh/id_ed25519_work

# Verify they're loaded (optional)
ssh-add -l

Step 3: Add public key to Github

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# Copy personal public key
cat ~/.ssh/id_ed25519_personal.pub
# → Copy the output

# Copy work public key
cat ~/.ssh/id_ed25519_work.pub
# → Copy the output

Step 4: Configure SSH config

The core of the whole setup. Edit ~/.ssh/config:

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# Personal
Host gh-personal # This is the alias for personal account's github domain
  HostName github.com
  User git # Github use git as user to authenticate into github using ssh (git@domain.com)
  IdentiyFile ~/.ssh/id_ed25519_personal
  IdentitiesOnly yes

# Work
Host gh-work # This is the alias for work account's github domain
  HostName github.com
  User git
  IdentiyFile ~/.ssh/id_ed25519_work
  IdentitiesOnly yes

• Host <aliases> - create a sematic alia for specific account.
• IdentitiesOnly yes - tell ssh to only use the specified key and do not try other key.

Step 5: Verify the setup

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# personal
ssh -T gh-personal

# work
ssh -T gh-work

Step 6: Setup remote url

For existing repos, update the remote URL:

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# personal
cd ~/personal/repo_personal
git remote set-url origin git@gh-personal:simon/repo_personal.git

# work
cd ~/work/repo_work
git remote set-url origin git@gh-work:simon-work/repo_work.git

# after setup url, verify with git command
git remote -v

References

• GitHub Docs: Managing multiple accounts — GitHub’s official guide on handling multiple accounts with SSH and HTTPS.
• GitHub Docs: Connecting to GitHub with SSH — Official walkthrough for generating keys and adding them to your account.
• GitHub Docs: Adding a new SSH key to your GitHub account — Step-by-step for uploading your public key.
• Git Documentation: git-config Conditional Includes — Official docs on includeIf with gitdir, gitdir/i, onbranch, and hasconfig.
• OpenSSH Manual: ssh_config — Full reference for all SSH config options (IdentityFile, IdentitiesOnly, Host, etc.).
• Arch Wiki: SSH keys — Arch-specific guide covering key generation, ssh-agent, and systemd integration.