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Frameworks & web · #fastify
Goal We want to deliver a high‑throughput, read‑only API where the JSON response shape is stable across many requests. Constraints Minimize per‑request CPU spent on serialization. Keep startup time acceptable for rapid deployment cycles. Maintain flexibility to change response schemas without a full rebuild. Ensure that error responses and non‑JSON payloads
Fastify request schema date-time validation and timezone conversion A design goal is to accept ISO 8601 date-time strings in request bodies and ensure they are handled in a canonical timezone, such as UTC or a configured regional zone, before business logic runs. Fastify uses AJV for schema validation. The format: 'date-time' keyword validates the string sha
Goal: Validate limit and offset query parameters in Fastify route schemas so large dataset endpoints cannot return unbounded result sets. Fastify does not enforce a global maximum page size. Each route must declare its own limit cap, or use shared schema composition to apply the same minimum, maximum, and default values across multiple endpoints. Offset-base
Timeout enforcement under concurrent sockets Fastify forwards requestTimeout , keepAliveTimeout , and connectionTimeout directly to Node's HTTP server. Their defaults and enforcement points changed across Node major versions, making timeout-related latency under many open sockets version-sensitive. Because Fastify does not create threads per request, handler
Goal Reduce memory overhead on a low‑traffic Fastify server by limiting the size of incoming request bodies. A stricter bodyLimit can prevent large payloads from consuming RAM, but it must be tuned to avoid breaking legitimate traffic. Constraints and Uncertainty The bodyLimit option is evaluated after decompression when fastify-compress is enabled, so the e
Goal Make a decorator added by one Fastify plugin visible to a sibling plugin registered later, without forcing the provider into the parent scope. Constraints Fastify evaluates encapsulate at registration time. With encapsulation enabled, decorators remain isolated inside the child plugin and are undefined in siblings. With encapsulation disabled, the decor
Goal is to prevent duplicate writes when clients retry POST requests that pass through Fastify routes to a downstream data store. Fastify provides no built-in idempotency or retry deduplication, so the integration boundary between the request lifecycle hooks/plugins and an external dedup store must be defined by application code. Encapsulation allows scoping
Authentication Scope and Plugin Encapsulation Implementing a least-privilege security model in Fastify often involves using preHandler hooks to restrict access to specific route groups. To maintain a clean architecture, authentication state is typically attached to the request object via decorators. When these authentication decorators and hooks are defined
NestJS 10 changed the default HTTP server from Express to Fastify, creating an integration boundary for teams that maintain Express-style middleware across version 9 and version 10 codebases. The precise goal is to determine which existing Express middleware patterns remain viable under the Fastify runtime without introducing runtime failures or hidden behav
express
nestjs