Open Source Developer

About the Role

mailkube is building first-class SDKs for the languages developers actually use, including Python, Java, PHP, TypeScript, and JavaScript. As an Open Source Developer on the Developer Experience team, you will own those libraries end-to-end: from API design and implementation to documentation, community engagement, and release automation.

This is a part-time, fully remote role. You will work autonomously on a small, focused team that cares deeply about the quality of what developers integrate into their applications.

What You’ll Do

• Build and maintain official mailkube SDKs across Python, Java, PHP, TypeScript, and JavaScript
• Design clean, idiomatic interfaces that feel native to each language and its ecosystem
• Write comprehensive documentation, guides, and real-world integration examples
• Triage issues and pull requests in public repositories; engage with external contributors
• Develop and maintain CI/CD pipelines for automated testing, versioning, and package publishing
• Collaborate with the API team to surface integration pain points and shape the developer experience
• Contribute to open standards and participate in the wider developer community on behalf of mailkube

What We’re Looking For

• 3+ years of software engineering experience with at least two of: Python, Java, PHP, TypeScript, JavaScript
• Experience publishing and maintaining open-source libraries or packages
• Strong written communication skills, since your code and your prose will both be read by thousands of developers
• Comfortable working async and independently, with minimal hand-holding
• A genuine interest in helping other developers succeed

Nice to Have

• Experience with email protocols or transactional email systems (SMTP, webhooks, deliverability)
• Familiarity with package ecosystems: PyPI, Maven Central, Packagist, npm
• Prior experience writing technical documentation or developer tutorials
• Contributions to notable open-source projects

What We Offer

• Fully remote and async-first, so you can work from anywhere
• Flexible part-time hours, no core hours required
• Annual learning budget
• Direct impact: your SDKs will be used in production by developers worldwide