Pino vs Winston (July 2026): Side-by-Side Comparison
TL;DR: Pino wins on performance: structured NDJSON by default and worker-thread transports that keep logging off the event loop. Winston wins on flexibility: the largest transport ecosystem and fully custom formats. New high-throughput services should default to pino; winston remains a sane choice where output flexibility matters more than speed.
Spec comparison
| Spec | Pino | Winston |
|---|---|---|
| First released | 2016 | 2010 |
| Philosophy | Do less in-process: fast NDJSON, offload the rest | Do everything in-process: formats, transports, flexibility |
| Default output | Structured NDJSON (one JSON object per line) | Configurable, JSON, printf-style, colorized, custom |
| Performance | Fastest mainstream Node logger; ~5x winston in pino's own benchmarks | Adequate for most apps; formatting pipeline adds overhead |
| Transport model | Worker-thread transports (v7+): off the event loop | In-process transports on the main thread |
| Ecosystem | pino-pretty, pino-http, pino-roll, OTel integrations | Largest transport catalog (files, HTTP, syslog, cloud services) |
| Framework ties | Default logger in Fastify; common in NestJS via nestjs-pino | Long-standing default choice in Express apps; nest-winston |
| Redaction | Built in (fast-redact paths) | Not built in, custom formats required |
| Child loggers | First-class and cheap (bound bindings) | Supported (child loggers with defaultMeta) |
| Best for | High-throughput services, container/K8s deployments | Apps needing many output targets and custom human-readable formats |
Feature matrix
| Capability | Pino | Winston |
|---|---|---|
| Structured JSON logs by default | ✓ | ~ |
| Worker-thread (off-event-loop) transports | ✓ | ✗ |
| Built-in sensitive-field redaction | ✓ | ✗ |
| Pretty-printed dev output | ✓ | ✓ |
| Large third-party transport catalog | ~ | ✓ |
| Custom log levels | ✓ | ✓ |
| HTTP request logging middleware | ✓ | ~ |
| Log rotation | ~ | ✓ |
| Multiple simultaneous destinations | ✓ | ✓ |
| OpenTelemetry log integration | ✓ | ✓ |
When pino wins
Pino wins wherever logging volume or latency matters. Its design premise is that a logger's job in-process is only to serialize a line of NDJSON as fast as possible: everything else (pretty printing, shipping to files or log services, rotation) belongs elsewhere. Since pino v7, that "elsewhere" is worker-thread transports, so even log shipping stays off the event loop; in production containers, most teams go further and just write to stdout, letting the platform collect it (see working with Docker logs). Built-in redaction handles PII paths without a custom format layer, child loggers make per-request context (requestId, traceId) nearly free, and pino-http wires it into any HTTP server. Fastify adopting pino as its default logger is the strongest ecosystem signal: the fastest mainstream Node framework picked the fastest mainstream logger.
When winston wins
Winston wins on configurability and reach. Its format pipeline (timestamp, colorize, align, printf, custom functions) produces exactly the output shape you want, and its transport catalog (built up over fifteen years) covers files with rotation (winston-daily-rotate-file), syslog, HTTP endpoints, and a long tail of third-party services with a package for nearly everything. If your requirements include "human-readable file logs on disk, rotated daily, plus JSON to a log service, plus colorized console" and you want all of it declared in one logger config, winston does that with less assembly than pino. It is also the incumbent: countless Express and NestJS codebases already have winston conventions, and for moderate traffic the performance difference is not the bottleneck. The honest framing: winston optimizes for the developer reading logs; pino optimizes for the system emitting them.
Migration notes (winston to pino)
The migration is mostly mechanical: both libraries expose leveled methods and child loggers, so call sites change little: the argument order differs (pino takes the merge object first, logger.info({ userId }, 'msg')), and winston formats map to pino options (redact, serializers, timestamp functions) or disappear entirely if you adopt the collector-side pattern. Replace winston transports with pino transports for files, or (the cleaner 2026 approach) log NDJSON to stdout and let an OpenTelemetry Collector or platform agent handle routing, rotation, and enrichment. Keep pino-pretty strictly for local development; production should always emit raw NDJSON so your log platform can index fields for the correlation workflows described in our observability vs monitoring guide.
Which should you choose?
- New service in 2026: pino. Structured-by-default and off-thread transports are the right defaults for containerized deployments.
- Using Fastify: pino, full stop. It is already there.
- Existing winston codebase with moderate traffic: keep winston; migrate only when profiling shows logging overhead or when standardizing on structured logs.
- Need many heterogeneous outputs (rotated files + syslog + HTTP + console) configured in-process: winston's transport catalog is still unmatched.
- Strict PII requirements: pino's built-in path redaction is one less custom layer to maintain and audit.
- Either way, emit JSON with trace/request IDs and ship via stdout + collector: the logger matters less than the structure of what it logs.
FAQ
Why is pino faster than winston?
Pino minimizes work on the main thread: it serializes straight to NDJSON with precomputed serializers, skips a pluggable formatting pipeline, and since v7 runs transports in worker threads so shipping logs to files or services happens off the event loop. Winston runs its format chain and transports in-process, so every log line costs more on the thread that serves your requests. In pino's published benchmarks the difference is roughly 5x on common cases.
Should I migrate from winston to pino?
Migrate if logging shows up in your latency profile, you are moving to high-throughput services, or you want structured logs without maintaining custom formats. The API gap is modest (both expose leveled loggers and child loggers) and the main work is replacing winston formats and transports with pino transports or a collector-side pipeline. If your winston setup is stable and your traffic is moderate, the migration is optional rather than urgent.
Which logger should I use with Fastify or Express?
Fastify ships with pino as its built-in logger, so with Fastify the decision is already made: configure it rather than replace it. Express has no default logger: pino-http gives you fast structured request logging, while winston with express-winston remains common in older codebases. For new Express services in 2026, pino-http is the stronger default.
Does winston block the Node.js event loop?
Not in the hard synchronous sense (transports write asynchronously) but all of winston's formatting and transport work executes on the main thread, so heavy logging competes with request handling. Pino's worker-thread transports move that work off the event loop entirely, which is the architectural difference behind most of the benchmark gap. Under bursty load this shows up as tail latency, not just throughput.
Why does structured logging matter for either choice?
Structured (JSON) logs are machine-parseable, so log platforms can index fields like userId or traceId instead of regex-scraping message strings. That is what makes logs correlatable with traces and metrics in an observability stack. Pino emits structured NDJSON by default; winston can produce identical output with format.json(), so the real difference is whether structure is the default or a configuration choice.
Logs record what your code did. Who logs your agents?
Whichever logger you pick, it records what your application code did. If that Node service now embeds AI agents (calling models, invoking tools, hitting internal APIs) a structured log line is no longer the full story: you also need to know which agent acted, under which identity, whether the action was within policy, and what it cost. Swfte Nexus provides that layer: it captures every AI-agent action via runtime hooks (the way pino-http captures every request), enforces policy in-flight, traces agents, identities, and connections, and attributes AI spend per agent. Pino or winston gives you the application's diary; Nexus gives you the agent's, see LLM observability for how they fit together.