Job Title: Senior Developer

Location: Guilford

Working Pattern: Hybrid

Contract Type: Full Time - Permanent

Company

Our client is an award-winning, privately owned value-added reseller and systems integrator, established in 1984 and headquartered in Guildford, Surrey. They partner with leading technology providers, including 8x8, BT, Calabrio, Five9, Fortinet, Microsoft, Mitel, and Zoom, delivering advanced technology that supports their vision of a connected and sustainable future.

More than just a reseller, our client differentiates themselves through in-house software development, strong professional services capability, and a consultative engagement model. Their teams specialise in business communications and collaboration, contact centre and unified communications solutions networking, AI, automation, and systems integration.

They focus on creating value, mitigating risk, and establishing long-term, trust-based customer partnerships.

Role Description

They boast a supportive, innovative, and customer-focused culture and values the development of its colleagues, offering extensive learning and growth opportunities within the company. Here, you're not just part of a team; you're part of a community dedicated to professional growth and excellence. 

If you're an experienced Senior Backend Developer looking to take the next step in your career, they’d love to hear from you.

This role would suit an enthusiastic developer to join a small Software Development Team, as they expand and extend their enterprise-level SIP platform and its associated REST APIs 

Role Responsibilities

Reporting to the Development Manager, the successful candidate will: 

• Further design, develop and improve our existing SIP platform and its various associated services

• Design and build value-add services around the above

• Design and develop integrations for external systems, including voice-recognition, transcription and sentiment-analysis AI-based services 

• Ensure secure software design and development, at all levels

• Analyse, trouble-shoot and provide robust resolutions to problems arising SIP/RTP and other platform issues

• Contribute towards defining/improving our secure development processes and policies, as well as ensuring compliance with security standards such as ISO27001 and PCI-DSS

Essential Skills & Experience

The successful candidate will have a proven, in-depth, working knowledge of: 

• Understanding of SIP/VOIP and associated protocols (SDP, RTP, RFC2833/RFC4733 etc) 

• Python or another OO Language (5+ years) 

• OO Design 

• HTTP/ReST APIS 

• Flask/Django, Jinja, Pytest, SQLAlchemy, Marshmallow 

• Secure Systems Design & Development (software & network level) 

• Wireshark for SIP/RTP trace analysis/fault-finding/problem-solving 

• Git/GitHub (or similar) 

• Docker containerisation 

• Linux (Ubuntu) based systems 

Additionally: Excellent written and verbal communications skills, both when dealing with technical and non-technical audiences, are also essential for this role. 

Desirable Skills & Experience

 Knowledge/experience of the following would prove advantageous for this role: 

• Freeswitch, its configuration and (for extra points!) its source code 

• A working understanding C/C++ (for occasional open-source troubleshooting and code changes) 

• Kamailio and its configuration 

• Auth0 / OAuth 2.0 

• Mongo DB 

• MySQL 

• GitHub Actions CI/CD (or similar) 

• ArgoCD/Kubernetes 

• WebRTC