Senior .NET Developer

WebBeds; Palma; On-site; EUR 60,000 - 90,000; Full time

Job summary

WebBeds in Palma, Spain seeks an experienced Senior Software Developer for the Connectivity area. You will work in a self-managed team, delivering high-throughput connectivity with C# and Go, and shaping technical standards. You will drive data-driven decisions, partner with QA, and mentor peers on best practices.

You will work on the connectivity layer behind search and supplier traffic, ensuring security, performance and reliability in a fast-paced, global travel tech environment.

Qualifications

• 5+ years of backend software development with production experience in C# (.NET) and/or Go
• Strong .NET performance knowledge, async/await internals and pooling
• Solid understanding of concurrency, threading, and race conditions
• Linux knowledge and understanding of HTTP clients
• Benchmarking and profiling to diagnose CPU, memory and GC issues
• Experience shipping safely in high-traffic production systems with feature flags
• Effective use of AI coding tools

Responsibilities

• Shape technical direction within a self-managed engineering team
• Build and evolve the connectivity layer behind search and supplier traffic
• Benchmark and profile in production and run data-driven experiments
• Ship changes safely with feature flags, rollout, rollback and parity checks
• Write clean, maintainable code following SOLID principles with security in mind
• Collaborate with QA to enable automated testing
• Lead by example and mentor less experienced engineers
• Raise technical debt ideas with supporting data
• Document specs and design decisions for knowledge sharing

Skills

C#

Go

Backend development

NET performance

Concurrency & multithreading

Linux basics

HTTP protocols

Benchmarks & profiling

Feature flags & rollout

AI coding tools

Tools

Kubernetes

AWS

Job description

WebBeds is one of the world's largest accommodation suppliers to the travel industry. We are a global company offering ground services (hotels, transfers, tours, activities) to travel professionals. Our products cover our full business needs, from distribution APIs, payment integrations, SAP integration, Data Lakes, User Interfaces, and others. Our search API reaches peaks of more than 50.000 requests per second, each one with tens or hundreds of hotels. And those numbers are growing every year.

"We design, deliver and support innovative solutions through engagement, collaboration and a fearsome passion for creating customer value" is our mission as an IT organization.

With this in mind, we strive to be at the leading edge of technology when it comes to building the platform that meets the needs of our customers. This translates to the use of latest .NET Core versions, K8S, microservices architecture, multiple clouds, CI/CD pipelines, automated testing or great monitoring and alerting systems, to name a few.

Our delivery teams have the creativity and freedom to express themselves by building innovative solutions to often complex problems and are challenged to reach higher levels daily. Our teams consist of product owners, QA engineers, Software Engineers, and people from across the business all working collectively and collaboratively. We have a very strong technical team from which you will be able to learn but are encouraged by new ideas and fresh thinking that you will bring with you.

What You Will Do On Your Journey With WebBeds.

As a Senior Software Developer in our Connectivity area, you will be an experienced member of a self-managed delivery team, living our values of Trust, Teamwork and Technology. You will work independently on complex parts of our high-throughput connectivity layer, contribute to technical decisions, and help the engineers around you grow through your knowledge and example.

Key Responsibilities

In this role you will:

• Shape technical direction: Engage in technical discussions within a self-managed engineering team, contributing your expertise to user story definition, refinement and planning, and help define and uphold the team's technical standards and best practices.
• Build the connectivity layer: Build and evolve the connectivity layer behind our search and supplier traffic in C# and Go, including a native component on the hot path, working independently on complex features and contributing to design and trade-off discussions.
• Decide with data: Benchmark and profile in production and run time-boxed experiments, making decisions based on data and being willing to drop an approach (your own included) when the numbers do not support it.
• Ship safely and own it: Ship changes safely at high volume using feature flags, incremental rollout, rollback and behaviour parity checks, and take responsibility for what you ship once it is live, including fixing performance and stability issues.
• Write quality code: Write clean, maintainable and efficient code following sound design patterns and SOLID principles, with security built into your work from the start.
• Partner with QA: Work with QA engineers on testing, contributing to a fully automated testing environment that helps the team ship with confidence.
• Lead by example: Work with other senior engineers to set a good technical example for less experienced team members, sharing knowledge through code reviews, pairing and day-to-day collaboration, and recognising the contributions of others.
• Raise technical debt: Raise technical debt and improvement ideas with the team, backing them up with data where you can.
• Document your work: Document your work clearly (specs, decision records, recommendations) so knowledge is shared and nobody becomes a single point of failure.

The skills we would love to see in your suitcase!

Must have

• 5+ years of backend software development, with strong production experience in C# (.NET) and/or Go, ideally both.
• Good .NET performance knowledge, including async/await internals, garbage collector behaviour, and using Span and pooling to reduce allocations.
• Solid understanding of concurrency and multithreading, including thread safety, locking and common pitfalls such as race conditions and deadlocks.
• Working knowledge of Linux and of how HTTP clients work under the hood (HTTP/1.1 and HTTP/2, connection pooling, TLS, DNS, timeouts and cancellation).
• Hands‑on experience benchmarking and profiling, including looking at percentiles rather than averages and diagnosing CPU, memory and garbage collection issues with real tooling.
• Experience shipping safely in high‑traffic production systems using feature flags, incremental rollout, rollback, metrics and tracing.
• Effective everyday use of AI coding tools.

Strong plus

• Deeper low‑level .NET experience such as native interop, unsafe code and pinning.
• Advanced concurrency knowledge down to the memory‑model level, such as atomics, memory ordering, compare‑and‑swap and lock‑free structures.
• Production experience in a systems language with manual memory control (Rust, C++, C or Zig).
• Deeper Linux systems knowledge such as process lifecycle, memory mapping, syscalls and scheduling.
• Experience with traffic control and load modelling, such as rate limiting, backpressure, prioritisation and load generation.
• Infrastructure and cost awareness on Kubernetes and AWS (CPU limits, instance choice, cost per million requests).

Nice to have

• Zero‑copy serialisation (for example FlatBuffers or Cap'n Proto), code generation, or fast JSON/XML parsing.
• Verifying concurrent code with sanitisers, fuzzing or model checkers.
• Redis at protocol level, OpenTelemetry beyond HTTP boundaries, or the internals of resilience tools such as Polly or Envoy.
• HTTP/3 and QUIC.
• Incremental migrations of large systems alongside external teams.
• Travel or hotel distribution domain knowledge.

How You Work

• You are a collaborative team player, adept at thriving within a self‑organized team structure and embracing shared responsibilities.
• You are comfortable with open questions and time‑boxed experiments; you take decisions based on data and drop your own ideas when the numbers say so.
• You communicate proactively and share knowledge to avoid silos.
• Fluent English communication skills, both written and oral.
• You are happy to follow our motto: Build it, Ship it, Support it!