Postmark API tokens are crucial for maintaining the security of your email system, and their exposure can lead to unauthorized access and data breaches. To safeguard your credentials, it's essential to follow industry-standard practices like those outlined by the Open Web Application Security Project (OWASP), which provide comprehensive guidance on web application security. These include storing API tokens in environment variables instead of source files, using secrets management tools for production, and ensuring configuration files are excluded from version control. Additionally, integrating security measures into your CI/CD pipeline, performing regular security audits, and following a credential rotation schedule are vital steps to prevent unauthorized access. Implementing pre-commit hooks and using tools like git-secrets can help catch exposed secrets early. By adhering to these practices and making secure coding the default within your development process, you protect both your email infrastructure and broader application, thereby maintaining the trust of your users.