Universal Response Systems

VoIP & Telecom Developer (Asterisk/Vicibox/SIP) Company: Universal Response Systems (URS) Location: India (Remote) Department: Engineering Software & QA Software Development Employment Type: Full-Time, Permanent Role Summary URS is building a cloud-hosted, open-source telecom stack from scratch to replace third-party dialers. We need a hands-on VoIP & Dialer Engineer who can architect, build, and ship the entire platform end-to-end: Asterisk/Vicibox dialer, SIP edge, multi-carrier routing, SMS/RVM, APIs, observability, and security. You build it; we’ll operate it day-to-day. Strong growth path to Technical Head as we scale. What You’ll Build & Own Core dialer: Stand up Asterisk/Vicibox/Vicidial in the cloud; design dial-plans (IVR/queues/recordings), AMD/voicemail detection, RVM (with guardrails). SIP edge & media: Deploy OpenSIPS/Kamailio (registrar/dispatcher/dialog), rtpengine/rtpproxy, TLS/SRTP, NAT traversal. Carriers & routing: Integrate multi-carrier SIP, implement LCR, intelligent failover, and QoS monitoring (ASR/ACD/PDD/MOS). Messaging: Build SMS/MMS via SMPP/REST (Twilio/Telnyx/Plivo/etc.) with DLR handling, throughput control, error normalization. APIs & integrations: Ship internal REST/webhook services (Node.js/Python) for CRM/dialer interop; signatures, retries, idempotency. Cloud & automation: AWS/GCP/Azure provisioning, VPC/SGs, Terraform/Ansible/Docker (K8s nice), backups/restore, multi-AZ design. Vicidial data layer: ETL and safe bulk ops across vicidial_list, vicidial_log, vicidial_agent_log, vicidial_closer_log, vicidial_campaigns, vicidial_statuses; MySQL/MariaDB tuning and index strategy for hot *_log tables. Number health & LNP: Automate DID lifecycle, caller-ID reputation monitoring/remediation, CNAM, number porting (LNP) tooling and cutovers. Observability & reliability: HOMER/siptrace, sngrep, Wireshark, SIPp probes, Grafana/ELK; SLOs, alerts, incident runbooks. Security: TLS/SRTP, SBC ACLs, fail2ban, secrets/RBAC; partner on DNC/TCPA plumbing and policy. Must-Have Skills VoIP core: Asterisk/Vicibox/Vicidial; SIP/RTP/SDP; dial-plans (extensions.conf/AEL/Lua), IVR/queues/recordings. SIP edge & media: OpenSIPS/Kamailio, rtpengine/rtpproxy, TLS/SRTP, NAT traversal. Cloud & IaC: AWS/GCP/Azure + Terraform/Ansible; Docker (K8s nice). Routing & QoS: Multi-carrier SIP, LCR, DNS SRV, QoS, codec tuning (G.711/G.729/Opus); KPI literacy (ASR/ACD/PDD/MOS). Code & integrations: Node.js or Python, REST/webhooks, webhook security; Linux; MySQL/MariaDB. Debugging: Wireshark, sngrep, SIPp; capacity/perf tuning for real-time systems. Numbers: DID lifecycle, caller-ID reputation workflows, LNP/porting execution. Nice-to-Have Asterisk internals: ARI/AMI/AGI, optional C/C++ module work (gdb, valgrind/gprof). WebRTC (STUN/TURN), softphone provisioning (Zoiper/Linphone). OpenSIPS/Kamailio clustering, geo-routing, multi-region HA/DR. Event streaming (Kafka/RabbitMQ); CDR analytics (ClickHouse/BigQuery); Grafana/ELK depth. Exposure to 10DLC/STIR/SHAKEN, trust hubs (Numeracle/TCR), spam-label mitigation. Education B.E./B.Tech (CS/IT/ECE/Telecom) preferred — equivalent hands-on Asterisk/Vicibox/SIP experience outweighs certificates.