Email Passionate Software Engineer

About Mission Inbox
At Mission Inbox, we help businesses ensure every email reaches its audience. Our platform empowers companies to build, monitor, and manage their own email infrastructure — eliminating deliverability blind spots and helping them stay ahead of increasingly strict spam filters. We’re growing fast and need engineers who are passionate about performance, reliability, and doing things right.

Role Overview
We’re looking for a Software Engineer with proven experience in email infrastructure and strong full-stack development skills in Python and Node.js. This role is perfect for someone who understands how mail servers, MTAs, and protocols work under the hood — and can turn that knowledge into clean, scalable code.
You’ll work directly with the CTO to architect and improve our core infrastructure, which powers our deliverability engine and high-volume sending systems.

Responsibilities

• Design, implement, and maintain email infrastructure components (Postfix, Dovecot, queueing systems, spam filtering, monitoring).
• Build and optimize backend services in Python and Node.js that support large-scale, high-performance email operations.
• Develop APIs and backend features to support our MI Shield and OBM Engine products.
• Configure and maintain MTA systems (Postfix, Exim, PowerMTA) for reliability and deliverability performance.
• Work with SPF, DKIM, DMARC, DNS, and authentication protocols to ensure compliance and reputation protection.
• Debug and optimize email delivery pipelines and system integrations.
• Collaborate closely with the CTO, DevOps, and frontend teams to ship improvements quickly and safely.
• Write clear, maintainable code and documentation for scalable and long-term maintainability.

Requirements

• 3+ years of experience in backend or infrastructure engineering.
• Strong proficiency in Python and Node.js (both required).
• Experience in the email industry — hands-on with MTAs, Dovecot, SMTP, IMAP, and DNS configurations.
• Fluent professional English (spoken and written). Clear communication is critical to collaborate effectively in a remote environment.
• Solid understanding of SPF, DKIM, and DMARC standards and their impact on deliverability.
• Experience with PostgreSQL and API development.
• Familiarity with Linux servers, shell scripting, and basic networking.
• Availability and responsiveness during 8 AM – 5 PM CST working hours.

Nice to Have

• Experience with multi-tenant SaaS applications or email service platforms.
• Knowledge of queue management systems, rate limiting, or bounce processing.
• Experience with CI/CD pipelines, Docker, or Kubernetes.
• Understanding of email analytics or anti-abuse systems.

Important Note – Commitment & Exclusivity
Our engineering team is amazingly committed, smart, and fast to deliver — and we expect the same from every new member. If you’re looking for a chill, relaxed job or plan to hold multiple positions, this is not the right role for you. We require full exclusivity and absolute dedication to our mission. Discovering that an employee holds another job will result in immediate termination. We value integrity, focus, and relentless execution — because that’s what it takes to build something extraordinary.