Java Software Engineer

JavaScript Software Engineer

Salford

Permanent | Full-time

Up to £60,000 per annum (negotiable)

DCS Technology are searching for a JavaScript Software Engineer to join our client and lead the delivery of a JavaScript-driven robust telephony infrastructure. This role offers the opportunity to work deeply with real-time communications technology, influencing architecture, performance, and user experience in a production environment.

Key responsibilities

• Design and build a JavaScript-based dial pad UI, using modern frameworks such as React, Vue, or vanilla JavaScript.
• Integrate the frontend dial pad with a backend PJSIP / pjproject SIP stack via services or bindings.
• Develop and maintain real-time, event-driven systems supporting voice calling and signalling.
• Work with WebRTC and ensure effective interoperability with SIP-based systems.
• Handle real-time audio concerns including microphone input, speaker output, echo cancellation, and latency optimisation.
• Collaborate on the design and implementation of SIP call flows, media handling, and call state management.
• Debug SIP signalling and media streams using tools such as Wireshark and SIP trace utilities.
• Ensure systems are secure, implementing best practices around TLS, SRTP, and authentication.
• Deploy and support services in Linux-based environments, ensuring stability and performance.
• Produce and maintain clear technical documentation aligned with development standards and change processes.

Key skills and experience:

• Strong JavaScript experience (Node.js and/or browser-based applications).
• Hands-on experience integrating PJSIP / pjproject via backend services or bindings.
• Solid understanding of VoIP fundamentals, including SIP, SDP, RTP/RTCP, codecs, and DTMF.
• Experience working with WebRTC and SIP interoperability.
• Proven ability to design and implement responsive, user-friendly dial pad interfaces.
• Experience building event-driven, real-time systems using WebSockets and asynchronous workflows.
• Familiarity with SIP servers such as Asterisk or FreeSWITCH.
• Strong debugging skills across signalling and media layers.
• Comfortable working in Linux environments.
• Good understanding of security principles relevant to VoIP and real-time communications.

What you get in return:

Salary: Up to £60,000

Benefits: Paid annual leave, pension, wellbeing perks and more

Career Development: Opportunities to grow with a company undergoing rapid expansion across multiple sectors

Interested?

Please submit your CV to Meg Kewley at DCS Engineering via the link provided.

Alternatively, email me at megan.kewley@dcsgroup.uk.com or call 0161 212 2308.