Standard library tour

The standard library is plain .nu source. You pull it in with $-imports. No separate package step is necessary. It spans six layers (239 modules total):

Layer	Path	Contents
`core`	`stdlib/core/`	Built into every program's assumptions: strings, vectors, Option/Result, slices, memory helpers
`std`	`stdlib/std/`	The general-purpose standard library: collections, I/O, time, threads, TLS 1.3, QUIC, post-quantum and classical crypto
`ext`	`stdlib/ext/`	Higher-level modules: HTTP/1.1, HTTP/2, HTTP/3, JSON, Protobuf, Zstandard, SQLite, PostgreSQL, package management, MCP
`net`	`stdlib/net/`	Sans-I/O protocol engines (TCP, UDP, DNS, DHCP, ARP, IPv4, Ethernet) and encrypted peer-to-peer transport
`dist`	`stdlib/dist/`	Distributed systems primitives: gossip, SWIM membership, Raft, CRDTs
`hal`	`stdlib/hal/`	Hardware abstraction layer: volatile MMIO and bare-metal microcontroller drivers

Every module is plain-text and readable. The fastest way to see a module's exact function signatures: use nurl_read_stdlib (via the NURL MCP server) or open the file under stdlib/ directly.

Core

Module	Contents
`string.nu`	the managed `String` type and its operations
`vec.nu`	`Vec[T]`, a growable array
`option.nu` / `result.nu`	combinators for `?T` and `!T E` — see Error handling
`slice.nu`	first-class tracked slice views (`slice_from_vec`, `slice_window`, `slice_of_str`)
`mem.nu`	low-level allocation helpers
`box.nu` / `cell.nu` / `pair.nu`	small owned-value wrappers
`char.nu`	character classification
`io.nu`	basic input/output
`errors.nu`	shared error-value shapes
`symtab.nu` / `posix.nu`	compiler/runtime-facing helpers

hashmap.nu, btree.nu, ordmap.nu (insertion-ordered map), set.nu, deque.nu, heap.nu, bitset.nu, lru.nu — plus arena.nu for bump-allocated batches, and arc.nu / rc.nu for shared ownership (Arc is thread-safe, Rc is single-threaded — see Concurrency).

Numbers, SIMD, and encoding

int.nu, float.nu, floatbits.nu, bigint.nu, decimal.nu, fft.nu, and simd.nu (v128 / v256 vector operations) for numeric work; encode.nu, utf8.nu, and unicat.nu (Unicode general categories and case folding) for text encoding; fmt.nu for formatted output.

I/O and the operating system

fs.nu (filesystem), pfile.nu (PFile: positional reads and writes shared by threads), mmap.nu (file_map read-only memory-mapped file views), bufio.nu (buffered I/O), path.nu, process.nu, args.nu, env.nu (ext/), signal.nu, term.nu, progress.nu, fswatch.nu.

Time and concurrency

time.nu, thread.nu (incl. Locked [T]), atomic.nu (Atomic), rwlock.nu (RwLocked [T]), channel.nu, async.nu, async_ffi.nu — see Concurrency for the full picture.

Networking

net.nu, dns.nu, udp.nu, unixsock.nu, url.nu, tls.nu, tls_server.nu, tls_verify.nu, and the pure-NURL QUIC stack (quic.nu, quic_pkt.nu, quic_crypto.nu, quic_conn.nu, quic_loss.nu, quic_tls.nu) in std/; the HTTP/1.1, HTTP/2, and HTTP/3 stack (http.nu, http_server.nu, http_router.nu, http_middleware.nu, http2_*.nu, http3_client.nu, http3_server.nu, http3_frame.nu, http3_qpack.nu, and more), websocket.nu, mqtt.nu in ext/. See Networking for a guided tour.

Cryptography

Post-quantum primitives mlkem.nu (FIPS 203 ML-KEM-512/768/1024), mldsa.nu (FIPS 204 ML-DSA-44/65/87), and slhdsa.nu (FIPS 205 SLH-DSA-SHAKE); classical primitives aes_gcm.nu, chacha20poly1305.nu, ecdsa_p256.nu, ed25519.nu, x25519.nu, rsa.nu; the hash_*.nu family (hash_sha256.nu, hash_sha512.nu, hash_sha3.nu for FIPS 202 SHA3/SHAKE, hash_blake2b.nu, hash_blake3.nu, hash_sha1.nu, hash_md5.nu); hkdf.nu, pbkdf2.nu, scrypt.nu, minisign.nu, subtle.nu (constant-time comparisons), x509.nu / x509_gen.nu, csr.nu (PKCS#10), pkey.nu (encrypted PKCS#8 v2), and ssh.nu / ssh_ed25519.nu in std/; crypto.nu, jwt.nu, http_jwt.nu in ext/. See Cryptography.

aes_gcm.nu runs on the language's hardware crypto tier where the CPU has AES-NI and PCLMULQDQ, or AES and PMULL on AArch64 (nurl_v128_aesenc, nurl_v128_clmul_*; ~3 GB/s on a Haswell, on par with the same kernel in C intrinsics), on its VAES tiers where the CPU has VAES and VPCLMULQDQ (nurl_v256_* on ymm, nurl_v512_* on zmm under AVX-512: two and four blocks per instruction, ~8–11 GB/s on a Sapphire Rapids) and on a constant-time bitsliced cipher everywhere else; TLS picks AES-128-GCM on such a CPU and ChaCha20-Poly1305 otherwise.

Data formats and serialization

json.nu, msgpack.nu, cbor.nu, protobuf.nu, toml.nu, yaml.nu, xml.nu, csv.nu, serde.nu (a Serialize trait), zip.nu, tar.nu, compress.nu, deflate.nu, and zstd.nu (pure-NURL RFC 8878 Zstandard compressor and decompressor).

protobuf.nu provides checked Protocol Buffers wire readers and writers for all scalar types, borrowed byte/submessage views, UTF-8 strings, packed fields and groups. Message schemas remain in application code. See the protobuf guide for the API, ownership contract, limits and examples.

Packages and the registry

manifest.nu, resolver.nu, semver.nu, lockfile.nu, registry_index.nu, pkg_fetch.nu, pkg_publish.nu, update_check.nu — the pieces nurlpkg is built from. See Editor and tooling.

Diagnostics and dev tools

bench.nu, log.nu, trace.nu, panic.nu (see Error handling), sort.nu, cmp.nu, random.nu, rng.nu, lifeguard.nu (false-positive suppression for failure detectors), dos.nu (abuse-resistance limits), nurldoc.nu.

Distributed computing and embedded

stdlib/net/ and stdlib/dist/ build a peer-to-peer stack — encrypted transport, NAT traversal, membership/failure detection, and CRDTs — on top of the socket layer above. See Distributed computing. stdlib/hal/ holds hardware-facing code (now an ESP32 memory-mapped I/O layer) for embedded targets — see Embedded targets. Both are advanced, opt-in layers.

Networking
Cryptography
Distributed computing and Embedded targets
Runnable examples for many of these modules are in examples/ — see Next steps.