Senior Software Engineer — Telecom Domain

Company Description Leino is a senior IT partner specializing in staff augmentation and full-cycle product development for clients in the telecom and technology sectors. The company quickly adds experienced engineers to client teams or builds products end-to-end, acting as a long-term partner invested in product success. Unlike traditional hiring or short-term freelancers, Leino focuses on reliability, continuity, and high-quality delivery. Based in Dubai (FZCO), Leino serves organizations across the GCC and globally, offering distributed, remote-first engineering capabilities.RequirementsTelecom domain experience (must-have)Substantial professional experience delivering software or systems inside the telecom industry — at an operator, vendor, MVNO, aggregator, or a company building products for them. The programming language does not matter. We work with and hire from Java, C/C++, Go, Python, Erlang/Elixir, Rust, C# and others; strong engineers pick up our stack quickly. What is not negotiable is that you already understand the domain.OSS / BSSPractical experience with operations and business support systems, such as: • Service provisioning and activation, order management, service and resource inventory • Mediation, rating, charging (online/offline), billing and revenue assurance • Fault, configuration, performance and network management (FCAPS), assurance and monitoring platforms • Customer management, product catalogue, self-care and partner-facing interfaces • Familiarity with TM Forum frameworks — eTOM, SID, Open APIs — and with commercial or open-source OSS/BSS suitesSIP and IMS signalling • Strong, hands-on command of SIP and SDP: registration, session setup and teardown, call flows, headers, error handling, and the failure modes you only learn in production • Media plane fundamentals: RTP/RTCP, codecs and transcoding, DTMF handling, NAT traversal • Experience with SBCs, softswitches, proxies and registrars, and with IMS core components (P-/I-/S-CSCF, HSS, TAS) • Confident with protocol analysis and troubleshooting tooling (e.g. Wireshark, sngrep, HOMER/HEP or equivalent) • SIP trunking and interconnect with carriers and partnersLTE, VoLTE and mobile core • Working knowledge of the EPC and its elements (MME, S/P-GW, HSS, PCRF) and of the interfaces between them • VoLTE end to end: bearer establishment and QoS/QCI, IMS registration over LTE, supplementary services, emergency calls, SRVCC and fallback behaviour • Diameter-based signalling and, where relevant, legacy SS7/SIGTRAN interworking • Exposure to 5G NSA/SA, VoNR, RCS or fixed–mobile convergence is a strong plusTelecommunication standards • Comfortable reading, interpreting and working directly from specifications: 3GPP, IETF RFCs (RFC 3261 and the surrounding SIP family), ETSI, ITU-T, GSMA and TM Forum • Able to reason about compliance, interoperability and versioning across vendors and releases, and to judge when a spec deviation in a partner’s implementation is the real root causeEngineering fundamentals • Senior-level software engineering practice: clean design, testing discipline, code review, CI/CD • Distributed systems, high availability, and systems that must not go down • Linux, networking fundamentals, containers and cloud or NFV/virtualised deployment environments • Databases and messaging appropriate to high-throughput, low-latency workloadsStrongly welcomed • Proven experience at telecom companies across EU, MENA and/or US markets. Multi-region background is highly valued — different regulatory regimes, interconnect practices and operator expectations produce engineers who design for variability rather than for one home market. • Familiarity with regional regulatory and compliance requirements: emergency services (112/911), number portability, lawful intercept, data protection (e.g. GDPR), and local interconnect rules • Roaming, international interconnect, wholesale voice or messaging experience • Experience migrating legacy telecom platforms to modern, cloud-native or virtualised architectures • Contributions to open-source telecom projects (Kamailio, OpenSIPS, FreeSWITCH, Asterisk, Open5GS, ONAP and similar) • Vendor or standards-body experience, or participation in interoperability testing