Senior Software Engineer

Senior Software Engineer

Location: Fareham, Hampshire
Working Pattern: Office-based during probation, then minimum 3 days onsite per week
Salary: £60k - £70k plus benefits

An opportunity has arisen for an experienced Senior Software Engineer to join an established and innovative technology business specialising in payment infrastructure and transaction processing.

This is an excellent opportunity for a talented backend engineer with strong commercial experience in either Go or PHP to work on business-critical systems that process real financial transactions.

You don't need experience in both languages. The business is looking for someone with strong expertise in one, with the opportunity to develop their skills in the other.

You'll join a collaborative engineering team working on modern microservices, APIs, distributed systems and large-scale software platforms, taking ownership of technical solutions from initial design through to production.

The Role

As a Senior Software Engineer, you'll be responsible for designing, developing and maintaining secure, scalable backend applications and services.

Working closely with frontend developers, DevOps engineers and security specialists, you'll contribute to a range of payment processing and CRM platforms.

Key responsibilities include:

• Design, develop and maintain backend services using Go and/or PHP.
• Build and enhance integrations with payment processors, fraud prevention services and third-party APIs.
• Develop secure, scalable APIs using REST, gRPC and Protocol Buffers.
• Work with relational and NoSQL databases, including MySQL, Cassandra, ScyllaDB and Elasticsearch.
• Contribute to microservices-based applications deployed using Kubernetes.
• Write clean, maintainable and well-tested code.
• Take ownership of production services, including monitoring, debugging and performance optimisation.
• Modernise existing applications and help reduce technical debt.
• Collaborate with engineering teams on architecture, design and technical improvements.
• Mentor other developers and contribute to engineering best practices.

Essential experience:

• Significant commercial backend software development experience.
• Strong programming experience in Go (Golang) OR PHP.
• For Go developers: experience with concurrency, HTTP services and/or gRPC.
• For PHP developers: strong PHP 8, object-oriented programming, Composer and PHPUnit experience.
• Strong SQL skills and experience with MySQL or similar relational databases.
• Experience designing, developing and integrating REST APIs, gRPC services or webhooks.
• Understanding of API reliability, error handling and secure coding practices.
• Experience writing automated tests and producing high-quality code.
• Familiarity with Git, code reviews and CI/CD pipelines.
• Strong problem-solving skills and the ability to take ownership of technical delivery.

Desirable Experience

Any of the following would be advantageous, although not essential:

• Commercial experience with both Go and PHP.
• Microservices and distributed systems architecture.
• Docker and Kubernetes.
• Messaging technologies such as RabbitMQ, NATS or Pub/Sub.
• NoSQL databases, including Cassandra, ScyllaDB or Elasticsearch.
• Protocol Buffers and API versioning.
• CRM platforms, subscription services or recurring billing systems.

Please contact Tom Rayner on 02380 765 808 or email

Spectrum IT Recruitment (South) Limited is acting as an Employment Agency in relation to this vacancy.