Build phases
Work through one meaningful runtime boundary at a time.
Build the
runtime yourself.
Seven working Node.js systems. Every lab includes an ordered phase plan, commands to run, failure cases to investigate, and concrete evidence to record.
A serious plan for every build.
Follow the phases in order, inspect the output, and make the engineering decisions yourself.
Checkpoints
Prove the behavior before adding the next abstraction.
Hint ladders
Get unstuck without losing the useful part of discovery.
Debug notes
Learn the shape of a failure before you repair it.
Expected output
Compare your result against observable evidence.
Rubrics
Inspect failure paths as carefully as the happy path.
Seven complete systems.
Start with the runtime problem you care about. Each lab stands on its own and ends with working code and evidence you can explain.
01process
Node Runtime Flight Recorder
Observe child processes, stdio, signals, memory, CPU, event loop delay, active handles, warnings, crashes, and runtime evidence.
child_process · perf_hooks · signals
02buffers
Binary File Store
Create an append-only log database with record checksums, indexed reads, crash recovery, tombstones, compaction, and benchmarks.
Buffer · fs · checksums
03streams
Stream Processing Workbench
Build an NDJSON pipeline, compare whole-file and streaming paths, expose backpressure, add gzip and aborts, then prove the tradeoffs.
pipeline · backpressure · gzip
04modules
Module Resolution Inspector
Trace import and require lookup, package exports, conditions, interop hazards, caches, cycles, symlinks, and resolver decisions.
ESM · CommonJS · exports
05filesystem
Atomic File Watcher
Scan directories, hash files, persist cache state, normalize uncertain filesystem events, debounce rebuilds, and verify every result.
fs.watch · hashing · build cache
06async flow
Async Task Runtime
Build a local job orchestrator with dependencies, concurrency limits, retries, timeouts, cancellation, durable progress, and reports.
scheduler · AbortController · events
07networking
Custom Binary Protocol Gateway
Design a byte-level protocol and TCP gateway with stateful parsing, malformed-frame defenses, bounded sinks, metrics, load, and reports.
node:net · binary framing · TCP
One book. Seven builds. No shortcuts.
Raw Mode includes every Runtime Lab, each downloadable edition, the framework build, practice material, and future updates.