Algorithms & Data Structures 2
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Understands the fundamentals of Algorithms & Complexity at a basic level. Applies simple concepts in work tasks using Node.js 20+/TypeScript. Follows recommendations from senior developers when solving problems.
Independently applies algorithmic thinking in Node.js: selects non-blocking algorithms for event loop efficiency, understands streaming algorithm patterns for memory-constrained processing, evaluates async operation scheduling. Analyzes complexity of data transformation operations in Express/Fastify middleware chains.
Sets performance budgets for Node.js services. Conducts reviews focused on event loop blocking, V8 optimizations. Implements benchmarking via clinic.js and autocannon in CI.
Defines Node.js platform performance strategy. Designs high-throughput solutions: streams for I/O, worker threads for CPU-bound, clustering. Balances throughput and event loop latency.
Understands the fundamentals of Data Structures at a basic level. Applies simple concepts in work tasks using Node.js 20+/TypeScript. Follows recommendations from senior developers when solving problems.
Independently selects appropriate data structures in Node.js: Map/Set vs plain objects for key-value operations, TypedArrays for binary data, Buffers for I/O operations. Understands trade-offs between data structure choices for V8 optimization and garbage collection pressure.
Defines data handling standards: TypeScript interfaces for API contracts, Zod schemas for validation, immutable data patterns. Reviews data structure choices in V8 memory management context.
Designs Node.js platform data models: shared TypeScript types via npm packages, Protocol Buffers for inter-service communication, streaming data processing via Node.js Streams API.
API Management 3
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Documents API: describes endpoints via JSDoc/swagger-jsdoc, writes request/response examples. Maintains Swagger UI up to date. Describes authentication requirements.
Generates API documentation: OpenAPI spec from NestJS decorators or Fastify schemas, Redoc for publishing. Documents: error codes, rate limits, pagination. Writes getting started guides.
Defines documentation standards: mandatory sections, review process, freshness requirements. Implements documentation-as-code and automated staleness detection.
Designs developer experience: API portal, SDK generation, interactive examples, developer onboarding. Defines documentation strategy for internal and external APIs.
Tests API via Postman/Insomnia: sends requests, validates responses. Writes basic tests in Postman Collections. Understands environments and variables.
Automates API testing: Supertest for integration tests, Postman/Newman in CI, contract testing (Pact). Tests error scenarios, edge cases, authentication flows.
Defines API testing standards: coverage requirements, mandatory contract tests, performance budgets. Implements automated API testing for all endpoints.
Designs API quality assurance: automated contract verification, breaking change detection, API conformance testing. Defines organizational API testing strategy.
Learns API versioning approaches such as URL path versioning and header-based versioning in Node.js services. Follows team conventions for maintaining backward compatibility in Express or Fastify routes.
Independently designs and implements API versioning strategies. Understands best practices and patterns. Writes documentation and API tests.
Defines versioning strategy: URL-based vs header vs content negotiation, deprecation policy, migration guides. Coordinates breaking changes between consumer and provider teams.
Designs API lifecycle management: versioning governance, sunset policies, automated compatibility checking. Defines organizational standards for API evolution.
API Protocols 1
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Implements WebSocket via Socket.IO/ws: client connections, rooms for grouping, events. Understands lifecycle: connect, disconnect, reconnection. Handles connection errors.
Designs real-time features: Socket.IO namespaces, presence tracking, message acknowledgment. Scales via Redis adapter. Implements binary data transfer and compression.
Defines real-time standards: WebSocket vs SSE vs polling decisions, connection limits, monitoring requirements. Conducts capacity planning for concurrent connections.
Designs real-time platform: edge WebSocket (CloudFlare Workers), connection routing, global presence system. Defines real-time strategy and technology selection.
Background Jobs & Task Queues 1
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Uses Task Queues at a basic level. Performs simple tasks following established templates. Understands basic concepts and follows team practices.
Independently implements tasks with Task Queues. Understands internals and optimizes performance. Writes tests.
Defines queue strategy: BullMQ for Node.js jobs vs Kafka for cross-service events, dead letter handling, idempotency standards. Implements monitoring and alerting for queue processing.
Designs distributed task processing: BullMQ for lightweight jobs, Kafka for heavy stream processing, temporal for long-running workflows. Defines orchestration patterns and SLA.
Caching 2
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Uses caching in Node.js at a basic level: in-memory caching with node-cache, Redis client integration. Follows team patterns for cache-aside in Express/Fastify middleware. Understands basic TTL configuration and cache key strategies.
Independently implements caching strategies in Node.js: multi-level caching with ioredis, HTTP response caching, and CDN cache headers. Understands cache stampede prevention, probabilistic early expiration, and cache invalidation patterns.
Defines caching strategy at product level. Establishes standards. Conducts design reviews and defines technical roadmap.
Defines caching strategy at company level. Evaluates new technologies and approaches. Shapes enterprise standards and reference architectures.
Uses Redis at a basic level. Performs simple tasks following established templates. Understands basic concepts and follows team practices.
Independently implements Redis caching patterns in Node.js services — cache-aside with ioredis, distributed locks with Redlock, and pub/sub for event broadcasting. Understands Redis memory policies, eviction strategies, and replication lag impacts. Writes comprehensive tests for cache consistency and failover scenarios.
Defines caching strategy: multi-level cache (in-memory + Redis), cache invalidation patterns, TTL policies. Establishes metrics and SLA for cache performance in Node.js services.
Designs caching platform: shared Redis infrastructure, cross-service cache coherence, partitioning strategy. Defines governance for cache patterns and capacity planning.
Concurrency & Parallelism 1
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Understands the fundamentals of Async Programming at a basic level. Applies simple concepts in work tasks using Node.js 20+/TypeScript. Follows recommendations from senior developers when solving problems.
Independently applies async programming in Node.js: async/await with proper error handling, Promise composition patterns, event-driven architecture with EventEmitter. Understands trade-offs between callbacks, promises, and streams in the Node.js event loop.
Defines Node.js async standards: async/await best practices, Promise concurrency (Promise.all vs allSettled), AsyncLocalStorage for context propagation. Implements async error handling standards.
Designs Node.js platform async architecture: event-driven messaging (BullMQ/NATS), streaming via Node.js Streams, backpressure handling. Defines scaling strategy for I/O-bound and CPU-bound workloads.
Data Modeling 2
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Designs models via Prisma schema: models, relations (1:1, 1:N, M:N), enums. Understands normalization. Uses Prisma relations for type-safe data access.
Independently designs schemas and optimizes queries for data modeling. Understands indexing and query execution plans. Uses Prisma/TypeORM effectively.
Defines modeling standards: naming conventions, Prisma schema conventions, documentation. Reviews models for DDD compliance and performance impact.
Designs platform data model: bounded context → database mapping, shared types via npm packages, event-driven data sync between services.
Writes migrations via Prisma Migrate / Knex migrations: creates tables, columns, indexes. Understands idempotency. Tests on dev environment.
Independently designs schemas and optimizes queries with database migrations. Understands indexing and query execution plans. Uses Prisma/TypeORM effectively.
Defines migration standards: Prisma Migrate vs Knex vs raw SQL, review process, rollback strategies. Tests on staging with production data copy.
Designs platform migration strategy: coordination between services, backward compatibility policy, data versioning. Defines schema evolution governance.
Database Optimization 2
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Creates indexes via Prisma/Knex migrations: @@index for composite, @@unique for constraints. Understands B-tree indexes. Checks EXPLAIN for query optimization.
Independently designs schemas and optimizes queries with database indexing. Understands indexing and query execution plans. Uses Prisma/TypeORM effectively.
Defines indexing standards: mandatory query plan review, index naming conventions, automated missing index detection. Balances read/write performance.
Designs platform indexing strategy: cross-service search indexes, automated maintenance. Defines indexing approaches for different storage engines (PostgreSQL, MongoDB, Elasticsearch).
Understands N+1 problem and solves via Prisma include/select, Knex eager loading. Uses findMany instead of findUnique loops. Analyzes generated SQL through logging.
Independently designs schemas and optimizes queries. Understands indexing and query execution plans. Uses Prisma/TypeORM effectively.
Defines query performance standards: time budgets, mandatory profiling. Implements slow query monitoring and automated alerts.
Designs data access strategy: CQRS, read replicas routing, materialized views, polyglot persistence. Defines SLA for query latency.
Distributed Tracing 1
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Connects OpenTelemetry to Node.js: @opentelemetry/auto-instrumentations-node for automatic tracing. Views traces in Jaeger. Understands spans and context propagation.
Configures OTel in Node.js: custom spans via @opentelemetry/api, baggage for context, exporter configuration. Integrates traces + metrics via OTel SDK.
Defines OTel standards: mandatory spans, resource attributes, instrumentation requirements. Implements tracing-based debugging workflow.
Designs OpenTelemetry platform: vendor-neutral observability, multi-signal correlation, OTel Collector scaling. Defines observability strategy.
Functional Programming 1
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Understands the fundamentals of Functional Programming Principles at a basic level. Applies simple concepts in work tasks using Node.js 20+/TypeScript. Follows recommendations from senior developers when solving problems.
Applies FP principles in Node.js: pure functions, immutability with Object.freeze or Immer, and function composition. Uses higher-order functions and map/filter/reduce effectively. Understands closures and currying for reusable utilities. Reviews code for unnecessary mutations and side effects.
Defines FP standards: pure functions for business logic, fp-ts/Effect for type-safe error handling, pipe/compose for data transformations. Balances FP and OOP approaches by context.
Shapes FP strategy for Node.js platform: Effect System for complex workflows, algebraic data types, functional error handling. Determines when FP vs OOP, plans adoption path.
GraphQL 1
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Creates GraphQL API via Apollo Server/Mercurius: type definitions, resolvers, queries and mutations. Understands schema-first vs code-first. Tests via GraphQL Playground.
Designs GraphQL schemas: input types for mutations, pagination (Relay connections), error handling. Optimizes: DataLoader for N+1, query complexity limits, persisted queries.
Defines GraphQL standards: schema design guidelines, federation strategy, deprecation policy. Implements schema review process and automated breaking change detection.
Designs GraphQL strategy: unified graph (Apollo Federation), schema governance, GraphQL vs REST trade-offs per use case. Determines when GraphQL is justified on the platform.
Message Queues & Event Streaming 2
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Understands Kafka basics for Node.js services: KafkaJS client setup, basic producer/consumer patterns, and async message processing with Node.js event loop considerations. Follows team practices for topic management and error handling in event-driven Node.js applications.
Implements Kafka integration for Node.js microservices: event sourcing patterns with KafkaJS, schema validation with Avro/Protobuf, and consumer group management for scalable processing. Handles backpressure in Node.js event loop during high-throughput consumption. Implements idempotent message processing and dead letter queue patterns.
Defines Kafka strategy: topic naming, schema evolution policy, KafkaJS vs Confluent SDK. Implements event-driven communication standards and consumer lag monitoring in Node.js services.
Designs event-streaming platform: Kafka + Node.js workers for stream processing, multi-cluster setup, event sourcing patterns. Defines governance for event contracts.
Uses RabbitMQ with amqplib/amqp-connection-manager in Node.js at a basic level. Publishes and consumes simple messages following team templates. Understands basic AMQP concepts: exchanges, queues, and bindings.
Independently implements RabbitMQ messaging patterns in Node.js: topic exchanges, RPC, work queues with prefetch. Configures connection recovery, channel pooling, and dead-letter handling. Writes tests for async message processing flows.
Defines RabbitMQ architectural standards for Node.js platform. Establishes messaging patterns, error handling conventions, and operational runbooks. Conducts design reviews for async communication patterns and queue topology decisions.
Defines enterprise messaging strategy evaluating RabbitMQ vs alternatives (SQS, Kafka, NATS). Shapes organization-wide async communication standards and reference architectures. Establishes messaging platform governance and technology evolution roadmap.
Networking 1
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Understands networking for Node.js: TCP/HTTP, DNS resolution, ports and binding. Configures CORS, proxy headers (X-Forwarded-For). Debugs connection issues.
Configures networking: keep-alive for HTTP connections, connection pooling for databases, service discovery. Diagnoses: timeouts, connection leaks, DNS caching in Node.js.
Designs network architecture: service mesh (Linkerd/Istio), gRPC for inter-service, HTTP/2 multiplexing. Optimizes: connection reuse, TCP tuning, TLS termination.
NoSQL Databases 1
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Understands MongoDB document model and basic CRUD operations using Mongoose or native driver. Writes simple queries and follows team conventions for schema design. Applies basic indexing principles and understands the difference between embedding and referencing documents.
Independently designs schemas and optimizes queries with MongoDB. Understands indexing and query execution plans. Uses Prisma/TypeORM effectively.
Defines data strategy at product level. Establishes MongoDB standards. Conducts data schema and scaling strategy reviews.
Designs MongoDB strategy for Node.js platform: Mongoose vs native driver, sharding strategy, Atlas vs self-hosted. Determines when MongoDB vs PostgreSQL based on data access patterns and consistency requirements.
OOP & Design Patterns 2
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Understands the fundamentals of Design Patterns at a basic level. Applies simple concepts in work tasks using Node.js 20+/TypeScript. Follows recommendations from senior developers when solving problems.
Independently applies design patterns for Node.js: middleware chain pattern in Express/Fastify, observer with EventEmitter, factory for service instantiation, strategy for pluggable implementations. Explains pattern trade-offs for async-first Node.js architectures.
Establishes Node.js team architectural standards: Middleware pattern (Express/Fastify), Repository pattern for data access, Dependency Injection (tsyringe/inversify). Conducts architectural reviews.
Defines Node.js platform architectural patterns: Event-Driven Architecture, CQRS, Circuit Breaker (opossum). Shapes reference architecture on NestJS/Fastify. Evaluates trade-offs.
Understands the fundamentals of OOP & SOLID Principles at a basic level. Applies simple concepts in work tasks using Node.js 20+/TypeScript. Follows recommendations from senior developers when solving problems.
Independently applies OOP/SOLID in Node.js/TypeScript: proper class hierarchies for services, interface segregation with TypeScript interfaces, dependency injection patterns (manual or with NestJS DI). Understands trade-offs between class-based OOP and functional patterns in the Node.js ecosystem.
Defines OOP standards for Node.js: TypeScript class patterns, interfaces for DI, abstract classes for base services. Trains on SOLID in NestJS context. Conducts design reviews.
Shapes Node.js platform object model. Determines where OOP (NestJS) is optimal vs FP (pure functions, composition) is preferred. Designs shared modules between services.
Relational Databases 1
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Works with PostgreSQL via Prisma/Knex: CRUD queries, relations, migrations. Understands PostgreSQL types (JSONB, arrays, UUID). Uses Prisma Studio for data inspection.
Independently designs schemas and optimizes queries with PostgreSQL. Understands indexing and query execution plans. Uses Prisma/TypeORM effectively.
Defines PostgreSQL standards: Prisma vs Drizzle vs TypeORM choice, migration workflow, query performance budgets. Conducts schema and access pattern reviews.
Designs data strategy: database-per-service, shared databases, read replicas routing. Determines when PostgreSQL vs MongoDB vs others for Node.js services.
REST API 1
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Creates REST API on Express/Fastify: CRUD endpoints, middleware for auth, error handling. Understands HTTP methods, status codes, content negotiation. Validates input via Zod/Joi.
Designs REST API: resource naming, pagination (cursor-based), filtering, sorting. Implements HATEOAS. Optimizes: response compression, ETags. Middleware pipeline for cross-cutting concerns.
Defines team API standards: design guidelines, naming conventions, error response format. Implements API review process and contract testing. Conducts API design reviews.
Designs platform API strategy: API gateway (Kong/AWS API GW), API marketplace, self-service API creation. Defines API governance and lifecycle management.
Type Systems 1
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Understands the fundamentals of Type Safety & Type Systems at a basic level. Applies simple concepts in work tasks using Node.js 20+/TypeScript. Follows recommendations from senior developers when solving problems.
Independently applies TypeScript type system for Node.js services — discriminated unions for API response types, branded types for domain identifiers, and conditional types for handler signatures. Understands trade-offs between runtime validation (zod/io-ts) and compile-time safety. Applies type narrowing techniques in code reviews.
Defines typing strategy: TypeScript strict mode, Zod for runtime validation, tRPC for end-to-end type safety. Controls tsconfig strictness and no-any policy.
Shapes Node.js platform typing standards: shared type packages, branded types for domain safety, type-safe ORM (Prisma/Drizzle). Evaluates new TypeScript features for adoption.
Web Frameworks 1
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Uses Node.js Frameworks at a basic level. Performs simple tasks following established templates. Understands basic concepts and follows team practices.
Independently builds applications with Express/Fastify/NestJS, understands middleware pipelines, dependency injection, and request lifecycle. Optimizes Node.js event loop performance and writes unit/integration tests with Jest/Mocha.
Defines framework strategy: NestJS for enterprise (DI, modules, guards), Fastify for high-performance API. Establishes conventions: project structure, module organization, shared libraries.
Defines organizational Node.js framework strategy: reference architecture, mono-repo setup (Nx/Turborepo), shared packages. Plans framework migrations and technology radar.