Node compatibility made a big leap across crypto, process, tty, and networking
March was dominated by Node parity work. Deno filled in major gaps in node:crypto (X.509 inspection, P-521, RSA-PSS, ChaCha20-Poly1305, Triple DES, constant-time secret-key/GCM checks, better key import/export and equality), node:process (argv/execPath, title, exit codes, unhandled rejections, process.unref(), thread CPU usage), node:tty (Windows/raw mode behavior, indestructible streams, synchronous writes), and child_process, dgram, dns, net, http, http2, and worker_threads. Several real-world edge cases were fixed too, including Windows named pipes, CONNECT/h2c handling, --inspect-brk, AbortSignal.any() leaks, and legacy node:domain behavior.
npm installs, resolution, and publishing got faster and more correct
The npm resolver was heavily reworked: peer dependency handling was split into more reliable phases, parallel metadata fetching and dedup fixes reduced hangs on large graphs, and BYONM/manual node_modules behavior was tightened for exact matches, version mismatches, and built-in shadowing. Install performance improved through abbreviated packument fetches, parallel lifecycle scripts, faster tarball extraction, and less blocking decompression. On the tooling side, deno install -g npm:... and npm install -g deno gained better bin shim handling, registry overrides and auth precedence were fixed, deno outdated now uses npm dist-tags correctly, and deno audit respects overrides more accurately.
Core runtime ordering, workers, and event loop behavior were refined
Multiple changes focused on matching Node/libuv timing semantics more closely: V8 microtasks now follow Node ordering, nextTick/immediate handling was consolidated, the event loop tick path was simplified, and libuv compatibility was repeatedly cleaned up. Worker behavior also improved with correct resource limits, cleaner shutdown/interrupt handling, synchronous TTY writes, better wakeups for foreground tasks, and safer async work handling across N-API and FFI. These changes reduce subtle timing bugs and improve stability under load.
Developer tooling got more useful: profiling, coverage, docs, and LSP
deno coverage gained function metrics and more accurate line accounting, while --cpu-prof got original-TypeScript source maps and new --cpu-prof-flamegraph SVG output for easier performance analysis. deno doc now understands npm dependencies, but also shipped a breaking JSON schema v2 overhaul. The LSP saw fixes for tsgo root syncing, organize-imports parity, JSX import-source caching removal, auto-import alias preservation, and notebook URI normalization. The node compat test harness also became easier to run and filter.
Telemetry, permissions, and safety fixes matured
OpenTelemetry support expanded with a built-in console exporter, stdout/stderr log tagging, array-valued attributes, better HTTP span semantics, and metric/error handling fixes. Permission auditing can now stream to OTEL, and several stability/security issues were addressed, including a nonblocking FFI use-after-free hazard, dynamic-import crash paths, Buffer length truncation, secret-key timing comparisons, and safer crypto validation.
Other misc changes
- Added prerelease channels and upgrade flow for
alphaandbetabuilds. deno compile/standalone binaries got argv and env-file behavior fixes.fspolyfills were further consolidated into internal modules.- CI/release workflows, cache keys, and version bumps were updated throughout the month.
- Smaller correctness fixes landed for readline, console formatting, Web APIs, SQLite, WebTransport, and import-map auto-imports.