Senior ultra-low-latency Network Engineer (Remote Spain)

Cactus; A distancia; EUR 60.000 - 80.000; Jornada completa

Descripción de la vacante

A leading software development company is looking for a skilled engineer specializing in high-performance networking code using C/C++. The position focuses on designing packet I/O pipelines and tuning Linux servers for ultra-low latency. Ideal candidates have hands-on experience with DPDK, strong networking tools knowledge, and excellent English communication skills. This full-time role offers competitive salary, flexible hours, and opportunities for professional growth.

Servicios

Competitive salary

Flexible working hours

Team events

Learning opportunities

Formación

• 5+ years of experience in C/C++ networking code.
• Experience with DPDK in production systems.
• Strong understanding of Linux and NIC features.

Responsabilidades

• Design and implement high-performance packet I/O pipelines.
• Configure and tune Linux servers for ultra-low latency.
• Ensure reliable operation at high packet rates.

Conocimientos

C / C++ expertise in performance-critical networking code

Hands-on experience with DPDK or similar

Strong knowledge of Linux performance tuning

Familiarity with RDMA concepts

Experience with packet capture tools

Strong problem-solving skills

Excellent English communication skills

Herramientas

tcpdump

Wireshark

perf

Descripción del empleo

Cactus is a software development company, providing full-cycle services for the European market. More than 170 companies increased business productivity using solutions developed by Cactus experts. The company has been regularly included in the listings of the best software development companies in Belgium and Europe.

This position is based in Spain, and you will collaborate with teams across Europe and an international partnership landscape.

What You Will Do

Design and implement high-performance packet I / O pipelines using DPDK or equivalent frameworks.

Adapt existing UDP application code to work with NIC queue–driven RX / TX loops, batch processing, and hardware offloads.

Configure and tune Linux servers for ultra-low latency : hugepages, NUMA awareness, CPU pinning, NIC driver binding, RSS / flow steering.

Ensure reliable operation at very high packet rates; instrument detailed throughput, latency, and packet-loss metrics.

Collaborate with the application team to integrate kernel-bypass transport with existing processing pipelines.

Stay current with RDMA and user-space networking trends (DPDK, netmap, AF_XDP, eBPF / XDP) to evaluate trade-offs.

What We Expect

Expert C / C++ in performance-critical networking code.

Hands-on experience with DPDK or similar (AF_XDP, netmap, PF_RING) in production systems.

Strong knowledge of Linux performance tuning and NIC hardware features (RSS, flow steering, checksum / jumbo offloads).

Familiarity with RDMA (RoCE, InfiniBand, iWARP) concepts and when to use them vs. raw packet I / O.

Experience with packet capture / analysis tools (tcpdump, Wireshark, perf).

Strong problem-solving and debugging skills at the network + OS boundary.

Excellent English communication skills – written and spoken.

Preferred Industry Backgrounds

• High-frequency trading (HFT) / fintech — ultra-low-latency networking engineers.
• Telecom / 5G / packet core — engineers building EPC, UPF, or fronthaul solutions.
• Network security & DPI appliances — intrusion detection / firewall data plane developers.
• CDN / video streaming / media transport — high-performance transport engineers.
• HPC / storage networking — experience with RDMA, NVMe-oF, or cluster interconnects.

What We Offer

Working with international clients.

An environment to develop your professional capabilities and take ownership.

Collaboration with a team of open, dynamic, and international experts.

Full-time position with a competitive salary and benefits, including learning opportunities.

Flexible working hours.

Get-together team events.