Come join our team!

Druid AI is an end-to-end platform for building, deploying, and scaling AI agents and Conversational Business Applications (CBA), designed to deliver next-level employee productivity and the total customer experience in the most intuitive way. Acting as a front layer to all digital operations, DRUID unifies and enhances the existing technology landscape while mitigating app fatigue.

With a 2x growth year over year, 160+ partners and 250+ clients worldwide, DRUID AI actively builds on its vision to provide employees with an intelligent virtual assistant that helps people work easier and faster.

We are looking for a Senior VoIP Engineer to architect and build a high-performance Session Border Controller (SBC) using the modern .NET ecosystem. You will be responsible for building a system that manages thousands of concurrent SIP sessions with sub-millisecond latency. You must be an expert in asynchronous programming and low-level networking within the C# environment.

What you’ll do at DRUID

• SIP Stack Development: Build or extend a SIP signaling engine in C# (e.g., working with SIPSorcery or building a custom implementation).
• High-Performance Networking: Implement high-throughput UDP/TCP socket management using System.Net.Sockets and Pipelines.
• Zero-Allocation Engineering: Optimize the media and signaling path to minimize Garbage Collection pressure using Span, ArrayPool, and stackalloc.
• Media Relay/Transcoding: Design a low-latency RTP media plane (experience with FFmpeg.NET or wrapping librtp is a plus).
• NAT & Security: Implement STUN/TURN/ICE logic and security features (TLS 1.3, SRTP) to ensure secure border traversal.
• Cloud Orchestration: Deploy the SBC as a containerized microservice (Docker/K8s) while managing the "VoIP-unfriendly" nature of cloud networking (static IPs, UDP timeouts).

What you’ll bring to DRUID

• Educational background: Bachelor's degree or higher
• Languages: Expert proficiency in C# and the .NET 8/9+ runtime. C/C++ knowledge is highly appreciated.
• Concurrency: Mastery of Task/ValueTask, Channels, and multithreading primitives.
• Protocol Knowledge: Deep understanding of RFC 3261 (SIP), SDP, and RTP/RTCP.
• Tools: Expert use of Wireshark, SNGREP, and .NET Profilers to identify latency bottlenecks.
• Infrastructure: Solid understanding of Linux networking (iptables, nftables) as the SBC will likely run on Linux containers.