Roles · Telecom Developer · Senior

What a Senior } should know

43 core skills, 58 in total. Expectations per skill, and what changes at the next level.

This page lists what a Senior } is expected to know and do, skill by skill. Core skills are the ones a manager and peers assess in a review cycle; the rest count only in self-assessment. Main areas: Programming Fundamentals, Backend Development, Database Management.

43core skills
15additional skills
12skill areas
100%at Advanced or Expert
Assess myself as Senior Full role matrix

Core skills for a Senior

Grouped by area. The label on the right is the expected depth: Awareness, Working, Advanced or Expert.

Programming Fundamentals · 7

Applies algorithmic expertise to telecom systems: call routing algorithms for optimal path selection, QoS scheduling algorithms for traffic prioritization, codec compression algorithms for media processing. Designs efficient signaling algorithms for carrier-grade throughput with minimal latency jitter.

Designs async architectures for telecom: non-blocking protocol processing pipelines, async call handling at carrier scale, concurrent signaling session management. Mentors team on async patterns for real-time telecom system performance.

Designs code quality standards for telecom systems: protocol implementation clarity, real-time processing code optimization, signaling module structure. Refactors legacy telecom stack components (SS7, SIP, Diameter) for modern maintainability. Establishes review practices for carrier-grade reliability and standards compliance.

Data Structures Advanced

Selects optimal data structures for telecom systems: ring buffers for real-time signaling message processing, hash tables for call session lookup by ID, priority queues for QoS packet scheduling. Optimizes data structures for carrier-grade throughput with minimal latency. Designs efficient protocol state machine representations for SIP/Diameter/GTP session management.

Design Patterns Advanced

Has deep expertise in design patterns for telecom systems: designs protocol-aware architectures with state machine and chain of responsibility patterns, implements resilient communication patterns for telecom reliability, optimizes pattern usage for real-time signaling performance. Mentors team on telecom-specific architectural patterns for multi-protocol systems.

Multithreading Advanced

Has deep expertise in telecom multithreading: designs high-performance concurrent call processing architectures, implements lock-free data structures for real-time signaling paths, optimizes thread scheduling for telecom latency requirements. Mentors team on concurrent programming patterns for telecom protocol stacks.

Applies OOP/SOLID in telecom system architecture: abstract protocol handler interfaces, strategy pattern for codec selection, factory method for session object creation. Designs extensible telecom frameworks with clean separation between signaling protocol layers, media processing, and call control logic.

Backend Development · 2

Apache Kafka Advanced

Designs Kafka architectures for telecom systems: high-throughput CDR/event processing pipelines, real-time network event correlation, and carrier-grade message delivery guarantees. Implements Kafka integration with telecom protocols (SIP, Diameter event streams). Optimizes for telecom-scale throughput (millions of events/second). Mentors team on event-driven telecom architecture.

Redis Advanced

Designs Redis caching architectures for telecom service platforms — subscriber session state management, CDR buffering for high-throughput billing events, and real-time network topology caching. Optimizes Redis for carrier-grade availability with cluster replication. Mentors team on caching strategies for telecom-scale concurrent session management.

Database Management · 1

PostgreSQL Advanced

Designs PostgreSQL architecture for telecom systems: optimizes database for high-volume CDR processing and real-time subscriber lookups, implements partitioning for time-series telecom data, configures replication for telecom service availability requirements. Mentors team on database patterns for telecommunications data workloads.

API & Integration · 3

Designs gRPC API architecture for carrier-grade telecom platforms — network function service mesh with proto schemas for 3GPP-aligned data models, streaming telemetry with gNMI patterns, and versioned network management contracts. Defines error handling for carrier-grade reliability and optimizes gRPC for high-throughput signaling workloads.

REST API Design Advanced

Designs API architecture for telecom platforms: carrier-grade API gateway patterns, real-time event notification APIs, subscriber management API at scale. Defines API contracts for telecom service orchestration. Mentors team on high-availability API design for telecom.

Designs WebSocket architecture for telecom platforms: carrier-grade connection management for millions of concurrent subscribers, protocol bridging between WebSocket and telecom signaling (SIP, Diameter), and edge-optimized WebSocket infrastructure. Implements telco-grade reliability with automatic failover and session persistence. Creates performance standards for real-time telecom communication.

Cloud & Infrastructure · 3

Docker Advanced

Designs Docker infrastructure for telecom services: containerized SIP/media server architecture, low-latency container networking for real-time communications, resource isolation for carrier-grade services. Implements best practices for telecom container reliability and failover strategies.

Kubernetes Core Advanced

Designs Kubernetes infrastructure for carrier-grade telecom network functions with 5G CNF requirements. Implements performance-optimized deployments with SR-IOV, DPDK, and real-time scheduling for latency-sensitive VNFs. Applies telecom-specific security hardening and implements high-availability patterns meeting carrier reliability standards.

Designs carrier-grade network architectures for telecom service delivery platforms. Implements advanced protocol stacks for 5G/IMS service chains with sub-millisecond latency requirements. Optimizes network function placement and traffic engineering for carrier-scale service performance. Applies security hardening for signaling and media plane separation.

Testing & QA · 3

Designs integration testing strategy for complex telecom service delivery platforms spanning signaling, media, and billing systems. Implements automated protocol conformance testing across SIP/IMS/Diameter interfaces. Optimizes test pyramid balancing protocol unit tests with end-to-end call scenario integration validation. Mentors team on testing carrier-grade reliability and failover integration points.

Load Testing Advanced

Designs load testing strategy for telecom platform: carrier-grade load simulation at scale (millions of concurrent calls/sessions), multi-protocol stress testing (SIP, Diameter, RTP), and production traffic replay for regression testing. Implements performance benchmarking for carrier certification. Creates capacity models for telecom infrastructure planning. Mentors team on telecom performance engineering.

Unit Testing Advanced

Designs testing strategy for telecom systems: test pyramid for protocol/signaling/integration layers, conformance testing for telecom standards (3GPP, SIP), load testing for concurrent call handling. Optimizes test execution with protocol simulators. Mentors team on testing carrier-grade reliability.

Security · 1

Network Security Advanced

Designs secure network architectures for telecom platforms: end-to-end encryption for signaling protocols (SIP-TLS, SRTP), multi-layer DDoS mitigation strategies, and secure interconnect designs between carrier networks. Mentors team on network security hardening for SS7/Diameter/GTP protocols and evaluates vendor solutions for telecom-grade firewalls and session border controllers.

AI-Assisted Development · 2

ChatGPT / Claude Advanced

Has deep expertise in applying ChatGPT/Claude for telecom system development. Designs AI-assisted workflows for protocol implementation, network function optimization, and conformance test generation. Optimizes prompt engineering for telecom engineering tasks and mentors team on leveraging AI for carrier-grade software development while maintaining safety standards.

GitHub Copilot Advanced

Designs GitHub Copilot adoption strategies for telecom teams: optimizes prompt engineering for protocol implementation code, implements specification compliance validation for AI-generated telecom code, evaluates Copilot effectiveness for standard-specific patterns. Mentors team on responsible AI-assisted telecom development.

Observability & Monitoring · 4

OpenTelemetry Advanced

Designs observability strategy for carrier-grade telecom platforms with OpenTelemetry — implements protocol-level distributed tracing across signaling chains, defines telecom-specific SLI/SLO for five-nines availability targets. Conducts network incident post-mortems and architects telemetry solutions for high-throughput signaling workloads.

Designs observability strategy for telecom platforms with Prometheus & Grafana: implements monitoring for signaling and media processing chains, defines SLI/SLO for telecom service quality metrics, conducts post-mortems for telecom outages. Mentors team on telecom-specific monitoring and alerting patterns.

SLI / SLO / SLA Advanced

Designs observability strategy for carrier-grade telecom platforms — implements protocol-level distributed tracing across signaling and media planes. Defines telecom-specific SLI/SLO frameworks covering five-nines availability, call quality metrics, and regulatory compliance indicators. Conducts network incident post-mortems and designs carrier-grade failover architectures.

Designs observability strategy for telecom platforms: implements distributed tracing across signaling and media processing chains, defines SLI/SLO for telecom service quality (call completion, latency, jitter), conducts post-mortems for telecom outages. Mentors team on logging patterns for multi-protocol telecom systems.

Version Control & Collaboration · 2

Code Review Advanced

Designs code review processes for telecom code: protocol implementation review standards, real-time processing review checklists, carrier-grade reliability review gates. Mentors team on reviewing telecom code for standards compliance and performance.

Git Advanced Advanced

Designs Git workflows for telecom teams: implements branching strategies for concurrent protocol development and certification branches, optimizes repository structure for multi-standard codebases, automates compliance-related tagging and release management. Mentors team on managing telecom-specific regulatory requirements through version control.

Networking & Telecom · 13

5G Core Network Advanced

Has deep expertise in 5G Core Network. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in BGP / OSPF Routing. Designs solutions for production systems. Optimizes and scales. Mentors the team.

DNS Deep Dive Advanced

Has deep expertise in DNS Deep Dive. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in HTTP/2 & HTTP/3 QUIC. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in Load Balancer Deep Dive L4/L7. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in Network Automation: Netmiko, NAPALM. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in Reverse Proxy: NGINX, Traefik, Caddy. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in Signaling Protocols. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in Software-Defined Networking (SDN). Designs solutions for production systems. Optimizes and scales. Mentors the team.

TCP/IP Deep Dive Advanced

Has deep expertise in TCP/IP Deep Dive. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in Telecom Billing Systems. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Has deep expertise in VoIP / SIP Protocol. Designs solutions for production systems. Optimizes and scales. Mentors the team.

WebRTC Advanced

Has deep expertise in WebRTC. Designs solutions for production systems. Optimizes and scales. Mentors the team.

Performance Engineering · 2

Designs low-latency telecom architectures: real-time media processing with hardware acceleration, carrier-grade signaling with bounded response times, and edge computing for latency-critical services. Implements end-to-end latency monitoring across network elements. Designs failover mechanisms that maintain latency SLAs. Mentors team on telecom-specific latency optimization patterns.

Architects high-capacity call processing systems handling tens of thousands of concurrent sessions with sub-millisecond signaling latency. Designs sharded signaling architectures that distribute SIP transaction load across clusters. Implements media stream optimization with hardware-accelerated transcoding and adaptive bitrate management to maximize channel capacity per chassis.

Additional skills

Not assessed by the team, but part of the self-assessment and the development plan.

API DocumentationAWSCursor IDEDatabase IndexingE2E TestingGitHub Actions / GitLab CIGraphQL DesignJWT / OAuth2 / OIDCOWASP & Application SecurityPrompt Engineering for CodeQuery OptimizationSecure Coding PracticesSystem Design FundamentalsTerraformType Safety & Type Systems

What changes at Lead

58 skills get a higher expectation or become core when moving from Senior to Lead. The biggest jumps first.

See the Lead page →
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} in the open competency matrix: 58 skills across 5 levels. The matrix is free for individuals and stays free.