We're excited to announce the release of Node.js 21! Highlights include updates of the V8 JavaScript engine to 11.8,
stable fetch and WebStreams, a new experimental flag to change the interpretation of ambiguous code
from CommonJS to ES modules (--experimental-default-type), many updates to our test runner, and more!

Node.js 21 will replace Node.js 20 as our ‘Current’ release line when Node.js 20 enters long-term support (LTS) later this month.
As per the release schedule, Node.js 21 will be ‘Current' release for the next 6 months, until April 2024.

Other Notable Changes

• [740ca5423a] - doc: promote fetch/webstreams from experimental to stable (Steven) #45684
• [85301803e1] - esm: --experimental-default-type flag to flip module defaults (Geoffrey Booth) #49869
• [705e623ac4] - esm: remove globalPreload hook (superseded by initialize) (Jacob Smith) #49144
• [e01c1d700d] - fs: add flush option to writeFile() functions (Colin Ihrig) #50009
• [1948dce707] - (SEMVER-MAJOR) fs: add globSync implementation (Moshe Atlow) #47653
• [e28dbe1c2b] - (SEMVER-MINOR) lib: add WebSocket client (Matthew Aitken) #49830
• [95b8f5dcab] - stream: optimize Writable (Robert Nagy) #50012
• [7cd4e70948] - (SEMVER-MAJOR) test_runner: support passing globs (Moshe Atlow) #47653
• [1d220b55ac] - vm: use default HDO when importModuleDynamically is not set (Joyee Cheung) #49950

Semver-Major Commits

• [ac2a68c76b] - (SEMVER-MAJOR) build: drop support for Visual Studio 2019 (Michaël Zasso) #49051
• [4e3983031a] - (SEMVER-MAJOR) build: bump supported macOS and Xcode versions (Michaël Zasso) #49164
• [5a0777776d] - (SEMVER-MAJOR) crypto: do not overwrite _writableState.defaultEncoding (Tobias Nießen) #49140
• [162a0652ab] - (SEMVER-MAJOR) deps: bump minimum ICU version to 73 (Michaël Zasso) #49639
• [17a74ddd3d] - (SEMVER-MAJOR) deps: update V8 to 11.8.172.13 (Michaël Zasso) #49639
• [e9ff81016d] - (SEMVER-MAJOR) deps: update llhttp to 9.1.2 (Paolo Insogna) #48981
• [7ace5aba75] - (SEMVER-MAJOR) events: validate options of on and once (Deokjin Kim) #46018
• [b3ec13d449] - (SEMVER-MAJOR) fs: adjust position validation in reading methods (Livia Medeiros) #42835
• [1948dce707] - (SEMVER-MAJOR) fs: add globSync implementation (Moshe Atlow) #47653
• [d68d0eacaa] - (SEMVER-MAJOR) http: reduce parts in chunked response when corking (Robert Nagy) #50167
• [c5b0b894ed] - (SEMVER-MAJOR) lib: mark URL/URLSearchParams as uncloneable and untransferable (Chengzhong Wu) #47497
• [3205b1936a] - (SEMVER-MAJOR) lib: remove aix directory case for package reader (Yagiz Nizipli) #48605
• [b40f0c3074] - (SEMVER-MAJOR) lib: add navigator.hardwareConcurrency (Yagiz Nizipli) #47769
• [4b08c4c047] - (SEMVER-MAJOR) lib: runtime deprecate punycode (Yagiz Nizipli) #47202
• [3ce51ae9c0] - (SEMVER-MAJOR) module: harmonize error code between ESM and CJS (Antoine du Hamel) #48606
• [7202859402] - (SEMVER-MAJOR) net: do not treat server.maxConnections=0 as Infinity (ignoramous) #48276
• [c15bafdaf4] - (SEMVER-MAJOR) net: only defer _final call when connecting (Jason Zhang) #47385
• [6ffacbf0f9] - (SEMVER-MAJOR) node-api: rename internal NAPI_VERSION definition (Chengzhong Wu) #48501
• [11af089b14] - (SEMVER-MAJOR) src: update NODE_MODULE_VERSION to 120 (Michaël Zasso) #49639
• [d920b7c94b] - (SEMVER-MAJOR) src: throw DOMException on cloning non-serializable objects (Chengzhong Wu) #47839
• [64549731b6] - (SEMVER-MAJOR) src: throw DataCloneError on transfering untransferable objects (Chengzhong Wu) #47604
• [dac8de689b] - (SEMVER-MAJOR) stream: use private properties for strategies (Yagiz Nizipli) #47218
• [1fa084ecdf] - (SEMVER-MAJOR) stream: use private properties for encoding (Yagiz Nizipli) #47218
• [4e93247079] - (SEMVER-MAJOR) stream: use private properties for compression (Yagiz Nizipli) #47218
• [527589b755] - (SEMVER-MAJOR) test_runner: disallow array in run options (Raz Luvaton) #49935
• [7cd4e70948] - (SEMVER-MAJOR) test_runner: support passing globs (Moshe Atlow) #47653
• [2ef170254b] - (SEMVER-MAJOR) tls: use validateNumber for options.minDHSize (Deokjin Kim) #49973
• [092fb9f541] - (SEMVER-MAJOR) tls: use validateFunction for options.checkServerIdentity (Deokjin Kim) #49896
• [ccca547e28] - (SEMVER-MAJOR) util: runtime deprecate promisify-ing a function returning a Promise (Antoine du Hamel) #49609
• [4038cf0513] - (SEMVER-MAJOR) vm: freeze dependencySpecifiers array (Antoine du Hamel) #49720

Semver-Minor Commits

• [3227d7327c] - (SEMVER-MINOR) deps: update uvwasi to 0.0.19 (Node.js GitHub Bot) #49908
• [e28dbe1c2b] - (SEMVER-MINOR) lib: add WebSocket client (Matthew Aitken) #49830
• [9f9c58212e] - (SEMVER-MINOR) test_runner, cli: add --test-concurrency flag (Colin Ihrig) #49996
• [d37b0d267f] - (SEMVER-MINOR) wasi: updates required for latest uvwasi version (Michael Dawson) #49908

Semver-Patch Commits

• [33c87ec096] - benchmark: fix race condition on fs benchs (Vinicius Lourenço) #50035
• [3c0ec61c4b] - benchmark: add warmup to accessSync bench (Rafael Gonzaga) #50073
• [1a839f388e] - benchmark: improved config for blob,file benchmark (Vinícius Lourenço) #49730
• [86fe5a80f3] - benchmark: added new benchmarks for blob (Vinícius Lourenço) #49730
• [6322d4f587] - build: fix IBM i build with Python 3.9 (Richard Lau) #48056
• [17c55d176b] - build: reset embedder string to "-node.0" (Michaël Zasso) #49639
• [f10928f926] - crypto: use X509_ALGOR accessors instead of reaching into X509_ALGOR (David Benjamin) #50057
• [136a96722a] - crypto: account for disabled SharedArrayBuffer (Shelley Vohr) #50034
• [17b9925393] - crypto: return clear errors when loading invalid PFX data (Tim Perry) #49566
• [ca25d564c6] - deps: upgrade npm to 10.2.0 (npm team) #50027
• [f23a9353ae] - deps: update corepack to 0.21.0 (Node.js GitHub Bot) #50088
• [ceedb3a509] - deps: update simdutf to 3.2.18 (Node.js GitHub Bot) #50091
• [0522ac086c] - deps: update zlib to 1.2.13.1-motley-fef5869 (Node.js GitHub Bot) #50085
• [4f8c5829da] - deps: update googletest to 2dd1c13 (Node.js GitHub Bot) #50081
• [588784ea30] - deps: update undici to 5.25.4 (Node.js GitHub Bot) #50025
• [c9eef0c3c4] - deps: update googletest to e47544a (Node.js GitHub Bot) #49982
• [23cb478398] - deps: update ada to 2.6.10 (Node.js GitHub Bot) #49984
• [61411bb323] - deps: fix call to undeclared functions 'ntohl' and 'htons' (MatteoBax) #49979
• [49cf182e30] - deps: update ada to 2.6.9 (Node.js GitHub Bot) #49340
• [ceb6df0f22] - deps: update ada to 2.6.8 (Node.js GitHub Bot) #49340
• [b73e18b5dc] - deps: update ada to 2.6.7 (Node.js GitHub Bot) #49340
• [baf2256617] - deps: update ada to 2.6.5 (Node.js GitHub Bot) #49340
• [a20a328a9b] - deps: update ada to 2.6.3 (Node.js GitHub Bot) #49340
• [3838b579e4] - deps: V8: cherry-pick 8ec2651fbdd8 (Abdirahim Musse) #49862
• [668437ccad] - deps: V8: cherry-pick b60a03df4ceb (Joyee Cheung) #49491
• [f970087147] - deps: V8: backport 93b1a74cbc9b (Joyee Cheung) #49419
• [4531c154e5] - deps: V8: cherry-pick 8ec2651fbdd8 (Michaël Zasso) #49639
• [9ad0e2cacc] - deps: V8: cherry-pick 89b3702c92b0 (Michaël Zasso) #49639
• [dfc9c86868] - deps: V8: cherry-pick de9a5de2274f (Michaël Zasso) #49639
• [186b36efba] - deps: V8: cherry-pick b5b5d6c31bb0 (Michaël Zasso) #49639
• [867586ce95] - deps: V8: cherry-pick 93b1a74cbc9b (Michaël Zasso) #49639
• [4ad3479ba7] - deps: V8: cherry-pick 1a3ecc2483b2 (Michaël Zasso) #49639
• [660f902f16] - deps: patch V8 to avoid duplicated zlib symbol (Michaël Zasso) #49639
• [f7c1d410ad] - deps: remove usage of a C++20 feature from V8 (Michaël Zasso) #49639
• [9c4030bfb9] - deps: avoid compilation error with ASan (Michaël Zasso) #49639
• [5f05cc15e6] - deps: disable V8 concurrent sparkplug compilation (Michaël Zasso) #49639
• [42cd952dbd] - deps: silence irrelevant V8 warning (Michaël Zasso) #49639
• [88cf90f9c4] - deps: always define V8_EXPORT_PRIVATE as no-op (Michaël Zasso) #49639
• [8609915951] - doc: improve ccache explanation (Chengzhong Wu) #50133
• [91d21324a9] - doc: move danielleadams to TSC non-voting member (Danielle Adams) #50142
• [34fa7043a2] - doc: fix description of fs.readdir recursive option (RamdohokarAngha) #48902
• [81e4d2ec2f] - doc: mention files read before env setup (Rafael Gonzaga) #50072
• [0ce37ed8e9] - doc: move permission model to Active Development (Rafael Gonzaga) #50068
• [3c430212c3] - doc: add command to get patch minors and majors (Rafael Gonzaga) #50067
• [e43bf4c31d] - doc: use precise promise terminology in fs (Benjamin Gruenbaum) #50029
• [d3a5f1fb5f] - doc: use precise terminology in test runner (Benjamin Gruenbaum) #50028
• [24dea2348d] - doc: clarify explaination text on how to run the example (Anshul Sinha) #39020
• [f3ed57bd8b] - doc: reserve 119 for Electron 28 (David Sanders) #50020
• [85c09f178c] - doc: update Collaborator pronouns (Tierney Cyren) #50005
• [099e2f7bce] - doc: update link to Abstract Modules Records spec (Rich Trott) #49961
• [47b2883673] - doc: updated building docs for windows (Claudio W) #49767
• [7b624c30b2] - doc: update CHANGELOG_V20 about vm fixes (Joyee Cheung) #49951
• [1dc0667aa6] - doc: document dangerous symlink behavior (Tobias Nießen) #49154
• [bc056c2426] - doc: add main ARIA landmark to API docs (Rich Trott) #49882
• [f416a0f555] - doc: add navigation ARIA landmark to doc ToC (Rich Trott) #49882
• [740ca5423a] - doc: promote fetch/webstreams from experimental to stable (Steven) #45684
• [f802aa0645] - doc: fix 'partial' typo (Colin Ihrig) #48657
• [6fda81d4f5] - doc: mention Navigator is a partial implementation (Moshe Atlow) #48656
• [6aa2aeedcb] - doc: mark Node.js 19 as End-of-Life (Richard Lau) #48283
• [0ee9c83ffc] - errors: improve performance of determine-specific-type (Aras Abbasi) #49696
• [4f84a3d200] - errors: improve formatList in errors.js (Aras Abbasi) #49642
• [cc725a653a] - errors: improve performance of instantiation (Aras Abbasi) #49654
• [d1ef6aa2db] - esm: use import attributes instead of import assertions (Antoine du Hamel) #50140
• [19b470f866] - esm: bypass CommonJS loader under --default-type (Geoffrey Booth) #49986
• [9c683204db] - esm: unflag extensionless javascript and wasm in module scope (Geoffrey Booth) #49974
• [05be31d5de] - esm: improve getFormatOfExtensionlessFile speed (Yagiz Nizipli) #49965
• [aadfea4979] - esm: improve JSDoc annotation of internal functions (Antoine du Hamel) #49959
• [7f0e36af52] - esm: fix cache collision on JSON files using file: URL (Antoine du Hamel) #49887
• [85301803e1] - esm: --experimental-default-type flag to flip module defaults (Geoffrey Booth) #49869
• [f42a103991] - esm: require braces for modules code (Geoffrey Booth) #49657
• [705e623ac4] - esm: remove globalPreload hook (superseded by initialize) (Jacob Smith) #49144
• [18a818744f] - fs: improve error performance of readdirSync (Yagiz Nizipli) #50131
• [d3985296a9] - fs: fix unlinkSync typings (Yagiz Nizipli) #49859
• [6bc7fa7906] - fs: improve error perf of sync chmod+fchmod (CanadaHonk) #49859
• [6bd77db41f] - fs: improve error perf of sync *times (CanadaHonk) #49864
• [bf0f0789da] - fs: improve error performance of writevSync (IlyasShabi) #50038
• [8a49735bae] - fs: add flush option to createWriteStream() (Colin Ihrig) #50093
• [ed49722a8a] - fs: improve error performance for ftruncateSync (André Alves) #50032
• [e01c1d700d] - fs: add flush option to writeFile() functions (Colin Ihrig) #50009
• [f7a160d5b4] - fs: improve error performance for fdatasyncSync (Jungku Lee) #49898
• [813713f211] - fs: throw errors from sync branches instead of separate implementations (Joyee Cheung) #49913
• [b866e38192] - http: refactor to make servername option normalization testable (Rongjian Zhang) #38733
• [2990390359] - inspector: simplify dispatchProtocolMessage (Daniel Lemire) #49780
• [d4c5fe488e] - lib: fix compileFunction throws range error for negative numbers (Jithil P Ponnan) #49855
• [589ac5004c] - lib: faster internal createBlob (Vinícius Lourenço) #49730
• [952cf0d17a] - lib: reduce overhead of validateObject (Vinicius Lourenço) #49928
• [fa250fdec1] - lib: make fetch sync and return a Promise (Matthew Aitken) #49936
• [1b96975f27] - lib: fix primordials typings (Sam Verschueren) #49895
• [6aa7101960] - lib: update params in jsdoc for HTTPRequestOptions (Jungku Lee) #49872
• [a4fdb1abe0] - lib,test: do not hardcode Buffer.kMaxLength (Michaël Zasso) #49876
• [fd21429ef5] - lib: update usage of always on Atomics API (Michaël Zasso) #49639
• [bac85be22d] - meta: ping TSC for offboarding (Tobias Nießen) #50147
• [609b13e6c2] - meta: bump actions/upload-artifact from 3.1.2 to 3.1.3 (dependabot[bot]) #50000
• [3825464ef4] - meta: bump actions/cache from 3.3.1 to 3.3.2 (dependabot[bot]) #50003
• [49f0f9ca11] - meta: bump github/codeql-action from 2.21.5 to 2.21.9 (dependabot[bot]) #50002
• [f156427244] - meta: bump actions/checkout from 3.6.0 to 4.1.0 (dependabot[bot]) #50001
• [0fe673c7e6] - meta: update website team with new name (Rich Trott) #49883
• [51f4ff2450] - module: move helpers out of cjs loader (Geoffrey Booth) #49912
• [7517c9f95b] - module, esm: jsdoc for modules files (Geoffrey Booth) #49523
• [b55adfb4f1] - node-api: update headers for better wasm support (Toyo Li) #49037
• [b38e312486] - node-api: run finalizers directly from GC (Vladimir Morozov) #42651
• [0f0dd1a493] - os: cache homedir, remove getCheckedFunction (Aras Abbasi) #50037
• [0e507d30ac] - perf_hooks: reduce overhead of new user timings (Vinicius Lourenço) #49914
• [328bdac7f0] - perf_hooks: reducing overhead of performance observer entry list (Vinicius Lourenço) #50008
• [e6e320ecc7] - perf_hooks: reduce overhead of new resource timings (Vinicius Lourenço) #49837
• [971af4b211] - quic: fix up coverity warning in quic/session.cc (Michael Dawson) #49865
• [546797f2b1] - quic: prevent copying ngtcp2_cid (Tobias Nießen) #48561
• [ac6f594c97] - quic: address new coverity warning (Michael Dawson) #48384
• [4ee8ef269b] - quic: prevent copying ngtcp2_cid_token (Tobias Nießen) #48370
• [6d2811fbf2] - quic: add additional implementation (James M Snell) #47927
• [0b3fcfcf35] - quic: fix typo in endpoint.h (Tobias Nießen) #47911
• [76044c4e2b] - quic: add additional QUIC implementation (James M Snell) #47603
• [78a15702dd] - src: avoid making JSTransferable wrapper object weak (Chengzhong Wu) #50026
• [387e2929fe] - src: generate default snapshot with --predictable (Joyee Cheung) #48749
• [1643adf771] - src: fix TLSWrap lifetime bug in ALPN callback (Ben Noordhuis) #49635
• [66776d8665] - src: set port in node_options to uint16_t (Yagiz Nizipli) #49151
• [55ff64001a] - src: name scoped lock (Mohammed Keyvanzadeh) #50010
• [b903a710f4] - src: use exact return value for uv_os_getenv (Yagiz Nizipli) #49149
• [43500fa646] - src: move const variable in node_file.h to node_file.cc (Jungku Lee) #49688
• [36ab510da7] - src: remove unused variable (Michaël Zasso) #49665
• [23d65e7281] - src: revert IS_RELEASE to 0 (Rafael Gonzaga) #49084
• [38dee8a1c0] - src: distinguish HTML transferable and cloneable (Chengzhong Wu) #47956
• [586fcff061] - src: fix logically dead code reported by Coverity (Mohammed Keyvanzadeh) #48589
• [7f2c810814] - src,tools: initialize cppgc (Daryl Haresign) #45704
• [aad8002b88] - stream: use private symbol for bitmap state (Robert Nagy) #49993
• [a85e4186e5] - stream: reduce overhead of transfer (Vinicius Lourenço) #50107
• [e9bda11761] - stream: lazy allocate back pressure buffer (Robert Nagy) #50013
• [557044af40] - stream: avoid unnecessary drain for sync stream (Robert Nagy) #50014
• [95b8f5dcab] - stream: optimize Writable (Robert Nagy) #50012
• [5de25deeb9] - stream: avoid tick in writable hot path (Robert Nagy) #49966
• [53b5545672] - stream: writable state bitmap (Robert Nagy) #49899
• [d4e99b1a66] - stream: remove asIndexedPairs (Chemi Atlow) #48150
• [41e4174945] - test: replace forEach with for..of in test-net-isipv6.js (Niya Shiyas) #49823
• [f0e720a7fa] - test: add EOVERFLOW as an allowed error (Abdirahim Musse) #50128
• [224f3ae974] - test: reduce number of repetition in test-heapdump-shadowrealm.js (Chengzhong Wu) #50104
• [76004f3e56] - test: replace forEach with for..of in test-parse-args.mjs (Niya Shiyas) #49824
• [fce8fbadcd] - test: replace forEach with for..of in test-process-env (Niya Shiyas) #49825
• [24492476a7] - test: replace forEach with for..of in test-http-url (Niya Shiyas) #49840
• [2fe511ba23] - test: replace forEach() in test-net-perf_hooks with for of (Narcisa Codreanu) #49831
• [42c37f28e6] - test: change forEach to for...of (Tiffany Lastimosa) #49799
• [6c9625dca4] - test: update skip for moved test-wasm-web-api (Richard Lau) #49958
• [f05d6d090c] - Revert "test: mark test-runner-output as flaky" (Luigi Pinca) #49905
• [035e06317a] - test: disambiguate AIX and IBM i (Richard Lau) #48056
• [4d0aeed4a6] - test: deflake test-perf-hooks.js (Joyee Cheung) #49892
• [853f57239c] - test: migrate message error tests from Python to JS (Yiyun Lei) #49721
• [a71e3a65bb] - test: fix edge snapshot stack traces (Geoffrey Booth) #49659
• [6b76b7782c] - test: skip v8-updates/test-linux-perf (Michaël Zasso) #49639
• [c13c98dd38] - test: skip test-tick-processor-arguments on SmartOS (Michaël Zasso) #49639
• [738aa304b3] - test: adapt REPL test to V8 changes (Michaël Zasso) #49639
• [de5c009252] - test: adapt test-fs-write to V8 internal changes (Michaël Zasso) #49639
• [8c36168b42] - test: update flag to disable SharedArrayBuffer (Michaël Zasso) #49639
• [6ccb15f7ef] - test: adapt debugger tests to V8 11.4 (Philip Pfaffe) #49639
• [c5de3b49e8] - test,crypto: update WebCryptoAPI WPT (Filip Skokan) #50039
• [4b35a9cfda] - test_runner: add test location for FileTests (Colin Ihrig) #49999
• [c935d4c8fa] - test_runner: replace spurious if with else (Colin Ihrig) #49943
• [a4c7f81241] - test_runner: catch reporter errors (Moshe Atlow) #49646
• [bb52656fc6] - Revert "test_runner: run global after() hook earlier" (Joyee Cheung) #49110
• [6346bdc526] - test_runner: run global after() hook earlier (Colin Ihrig) #49059
• [0d8faf2952] - test_runner,test: fix flaky test-runner-cli-concurrency.js (Colin Ihrig) #50108
• [b1ada0ad55] - tls: handle cases where the raw socket is destroyed (Luigi Pinca) #49980
• [fae1af0a75] - tls: ciphers allow bang syntax (Chemi Atlow) #49712
• [766198b9e1] - tools: fix comments referencing dep_updaters scripts (Keksonoid) #50165
• [760b5dd259] - tools: remove no-return-await lint rule (翠 / green) #50118
• [a0a5b751fb] - tools: update lint-md-dependencies (Node.js GitHub Bot) #50083
• [69fb55e6b9] - tools: update eslint to 8.51.0 (Node.js GitHub Bot) #50084
• [f73650ea52] - tools: remove genv8constants.py (Ben Noordhuis) #50023
• [581434e54f] - tools: update eslint to 8.50.0 (Node.js GitHub Bot) #49989
• [344d3c4b7c] - tools: update lint-md-dependencies (Node.js GitHub Bot) #49983
• [7f06c270c6] - tools: add navigation ARIA landmark to generated API ToC (Rich Trott) #49882
• [e97d25687b] - tools: use osx notarytool for future releases (Ulises Gascon) #48701
• [3f1936f698] - tools: update github_reporter to 1.5.3 (Node.js GitHub Bot) #49877
• [8568de3da6] - tools: add new V8 headers to distribution (Michaël Zasso) #49639
• [86cb23d09f] - tools: update V8 gypfiles for 11.8 (Michaël Zasso) #49639
• [9c6219c7e2] - tools: update V8 gypfiles for 11.7 (Michaël Zasso) #49639
• [73ddf50163] - tools: update V8 gypfiles for 11.6 (Michaël Zasso) #49639
• [817ef255ea] - tools: update V8 gypfiles for 11.5 (Michaël Zasso) #49639
• [f34a3a9861] - tools: update V8 gypfiles for 11.4 (Michaël Zasso) #49639
• [9df864ddeb] - typings: use Symbol.dispose and Symbol.asyncDispose in types (Niklas Mollenhauer) #50123
• [54bb691c0b] - util: lazy parse mime parameters (Aras Abbasi) #49889
• [1d220b55ac] - vm: use default HDO when importModuleDynamically is not set (Joyee Cheung) #49950
• [c1a3a98560] - wasi: address coverity warning (Michael Dawson) #49866
• [9cb8eb7177] - wasi: fix up wasi tests for ibmi (Michael Dawson) #49953
• [16ac5e1ca8] - zlib: fix discovery of cpu-features.h for android (MatteoBax) #49828