Senior macOS Developer

DNSFilter’s mission is to protect our customers and partners with products they love to use! We are revolutionizing network security by providing fast, accurate, and reliable threat protection and content filtering. We're a rapidly growing company dedicated to creating a safer internet for businesses and organizations worldwide. Leveraging AI-driven threat intelligence, DNSFilter empowers our customers to proactively block threats before they impact their networks. We foster a collaborative, innovative, and results-oriented culture where every team member contributes to our mission of making the internet safer.

As we continue our product-fueled growth by adding new features and broadening our solution to meet the needs of the global market, it's clear there's a missing piece. That's where you come in!

We are looking for a Senior Software Engineer specializing in macOS development, focusing on System Extensions and DNS traffic interception. As part of our Product Engineering organization, you will design, build, and maintain a macOS and iOS system extension and companion app that intercepts and routes DNS traffic to our secure DNSFilter servers for intelligent filtering and protection.

This is a full-time, remote role. Eligible candidates thrive in a fast-paced, globally distributed SaaS environment, are self-motivated, and have experience building and deploying macOS networked applications at scale.

We recognize that people come with a wealth of experience and talent beyond just the technical requirements of a job. If you feel like this job is for you, please apply. We believe diversity of experience and skills, including transferable skills, combined with passion, is a key to innovation and excellence; therefore, we encourage people from all backgrounds to apply to our positions!

In this Role, You Will: 

• Be a key member of our Product Engineering organization, developing our next-generation macOS client application and System Extension that securely intercepts and routes DNS/network traffic.
• Design, build, and maintain a NetworkExtension-based application using Apple’s NEDNSProxyProvider and/or NEFilter* frameworks to filter and control DNS queries.
• Collaborate closely with QA and product teams to define requirements and acceptance criteria for new features.
• Deliver real business value to our customer base
• Expand your knowledge on all technologies within our ecosystem

To Qualify for this Role, You Have:

• 5+ years of experience developing and maintaining macOS applications.
• Expertise in low-level networking optimization and troubleshooting kernel-level network bottlenecks.
• Proven experience with low-level networking, including socket programming and packet-level data manipulation.
• Strong experience with System Extensions (SEXT) and NetworkExtension frameworks (NEDNSProxyProvider, NEFilterControlProvider, etc.).
• Deep understanding of DNS fundamentals, including TCP/IP, DoH, and DoT protocols.
• Proficiency in Swift and Objective-C, with additional experience in Go, C, or C++ preferred.
• Familiarity with macOS development tools (Xcode, Instruments, lldb, tcpdump, Wireshark).
• Experience with code signing, entitlements, provisioning profiles, and notarization.
• Knowledge of MDM platforms (Jamf, Mosyle) and deployment best practices in enterprise environments.
• Experience with Git, modern CI/CD pipelines, and automated testing frameworks.
• Strong communication skills and comfort working in distributed, asynchronous teams.
• Availability to work hours overlapping 9am–5pm EST, Monday–Friday.

Bonus points for: 

• Deep knowledge of macOS internals and system-level debugging.
• Experience implementing DNS filtering, proxying, or network interception technologies.
• Familiarity with continuous integration systems (GitHub Actions, Jenkins, etc.).
• Experience with scripting languages (Python, Shell, or Go) for build and deployment automation.
• Exposure to TLS, mutual authentication, or certificate pinning.
• Understanding of endpoint protection, security auditing, or privacy compliance standards.
• Close proximity to our Tampa, FL office