Roles · Backend Developer (C#/.NET) · Principal
45 core skills, 67 in total. Expectations per skill, and what changes at the next level.
This page lists what a Principal } 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.
Grouped by area. The label on the right is the expected depth: Awareness, Working, Advanced or Expert.
Defines .NET platform performance strategy. Designs solutions for high-throughput processing via Span<T>, Memory<T>, System.IO.Pipelines. Balances throughput, latency and GC pressure at architecture level.
Designs .NET platform async architecture: event bus (MassTransit/NServiceBus), message broker, System.Threading.Channels for high-throughput. Defines backpressure and scaling strategy.
Defines .NET platform technical debt strategy. Plans migration (.NET Framework → .NET 8+). Establishes quality metrics and processes for maintaining codebase.
Designs .NET platform data models: gRPC/Protobuf for inter-service communication, System.Text.Json source generators for serialization. Defines high-performance data processing strategy.
Defines .NET platform architectural patterns: Clean Architecture, Vertical Slice, Event-Driven. Shapes reference architecture on ASP.NET Core. Evaluates trade-offs for business context.
Designs platform-level generic frameworks: source generators for compile-time generics, generic math (INumber<T>), type-safe pipeline builders. Evaluates new C# version capabilities.
Designs .NET platform concurrency model: thread pool tuning, lock-free patterns, System.IO.Pipelines for I/O-bound workloads. Evaluates .NET capabilities for high-frequency trading and real-time processing.
Shapes .NET platform object model. Determines where OOP is optimal vs functional approach (F#-style, LINQ). Designs shared kernel and domain events between services.
Shapes .NET platform typing standards. Evaluates C# evolution (discriminated unions, roles/extensions) and plans adoption. Designs type-safe inter-service contracts.
Designs organizational event-streaming platform: multi-cluster, MirrorMaker 2, Kafka Connect for CDC from SQL Server. Defines governance for event contracts and schema registry.
Defines ASP.NET Core strategy at company level. Evaluates new technologies and approaches. Shapes enterprise standards and reference architectures.
Shapes enterprise caching strategy for .NET platform: CDN + application cache + database cache layers, cache budgets per service. Defines data freshness requirements for business domains and establishes cross-team caching governance standards.
Designs organizational search platform: multi-tenant indexes, cross-cluster search, ML-based ranking. Defines indexing standards.
Defines enterprise messaging strategy evaluating RabbitMQ vs alternatives (Azure Service Bus, Kafka). Shapes company-wide event-driven architecture standards and reference implementations. Establishes messaging governance and migration roadmaps.
Designs organizational caching platform: shared Redis infrastructure, partitioning strategy, cross-service cache coherence. Defines governance for cache keys and TTL policies.
Designs platform data model: bounded context → database mapping, shared entities via domain events, data mesh. Defines schema evolution strategy.
Designs platform indexing strategy: cross-service search indexes, automated maintenance, capacity planning for I/O. Defines read vs write performance trade-offs.
Designs platform migration strategy: coordination between services, database-per-service, backward compatibility policy. Defines data versioning approach.
Designs data strategy: sharding, migration from monolithic DB to database-per-service, backup and DR. Determines when MySQL vs PostgreSQL vs SQL Server.
Designs PostgreSQL platform: logical replication, Citus for distributed queries, TimescaleDB for time-series. Defines migration strategy.
Designs platform data access strategy: CQRS, materialized views, polyglot persistence. Defines SLA for query latency by operation type.
Designs platform consistency model: strong vs eventual consistency by domain. Defines distributed transaction strategy between .NET services.
Shapes documentation platform: unified portal for all APIs, automated SDK generation, interactive sandbox. Defines documentation governance.
Shapes organizational versioning strategy: unified rules, deprecation governance, cross-team coordination. Defines SLA for backward compatibility.
Shapes organizational GraphQL platform: supergraph, schema governance, query analytics. Determines when GraphQL vs REST vs gRPC.
Shapes organizational API strategy: API Gateway, developer portal, governance. Defines standards for public and internal APIs. Designs API platform.
Shapes container strategy: registry, image governance. Defines standards for .NET optimizations (AOT, chiseled containers, ReadyToRun).
Designs K8s platform: multi-cluster, platform engineering, cost optimization. Defines standards for .NET workloads.
Shapes organizational Azure strategy: landing zone, Azure DevOps vs GitHub, Azure-native services vs portable. Defines standards for .NET on Azure: App Service vs AKS vs Container Apps.
Shapes CI/CD platform: shared runners, reusable pipeline library, deployment governance. Defines DORA metrics and improvement process.
Shapes integration testing platform: shared Testcontainers, test environment orchestration, E2E across services.
Shapes organizational testing culture: TDD/BDD standards, testing frameworks, shared infrastructure. Defines quality metrics.
Shapes testing infrastructure: custom Testcontainers modules for platform .NET services, shared infrastructure.
Shapes organizational testing framework: shared test libraries, best practices, automated quality reporting.
Shapes identity platform: centralized IAM, federation (Azure AD/Entra), zero-trust. Defines auth standards for all services.
Shapes security program: OWASP SAMM assessment, security champions, bug bounty. Defines governance for all .NET services.
Defines secure development lifecycle: security requirements, threat modeling, testing, incident response. Shapes security culture.
Defines organizational AI development strategy. Governance: compliance, IP, quality gates for AI-generated code.
Shapes architectural culture: reference architecture, domain/application/infrastructure layers. Shared kernel. Determines when clean architecture is justified.
Defines architectural strategy: reference architecture on ASP.NET Core, inter-service communication standards. Plans platform evolution.
Shapes OpenTelemetry platform: collector infrastructure, backend, correlation. Observability budget and governance.
Shapes observability platform: standards for .NET services, SLO framework, cost management. End-to-end visibility.
Shapes observability strategy: unified standards for all .NET services, centralized platform (Seq/ELK/Loki). SLI/SLO based on logs.
Organizational review standards: cross-team review, architectural review board, quality gates. Engineering excellence culture.
Versioning strategy: mono vs multi-repo, release management, NuGet package versioning. Coordinates releases between services.
Not assessed by the team, but part of the self-assessment and the development plan.
} in the open competency matrix: 67 skills across 5 levels. The matrix is free for individuals and stays free.