Go Standard Packages

PathSynopsis
archive/tarPackage tar implements access to tar archives.
archive/zipPackage zip provides support for reading and writing ZIP archives.
bufioPackage bufio implements buffered I/O.
builtinPackage builtin provides documentation for Go's predeclared identifiers.
bytesPackage bytes implements functions for the manipulation of byte slices.
cmd/asmAsm, typically invoked as ``go tool asm'', assembles the source file into an object file named for the basename of the argument source file with a .o suffix.
cmd/cgoCgo enables the creation of Go packages that call C code.
cmd/compileCompile, typically invoked as ``go tool compile,'' compiles a single Go package comprising the files named on the command line.
cmd/compile/internal/amd64
cmd/compile/internal/arm
cmd/compile/internal/arm64
cmd/compile/internal/gc
cmd/compile/internal/mips64
cmd/compile/internal/ppc64
cmd/compile/internal/s390x
cmd/compile/internal/ssa
cmd/compile/internal/syntax
cmd/compile/internal/x86
cmd/coverCover is a program for analyzing the coverage profiles generated by 'go test -coverprofile=cover.out'.
cmd/dist
cmd/docDoc (usually run as go doc) accepts zero, one or two arguments.
cmd/fixFix finds Go programs that use old APIs and rewrites them to use newer ones.
cmd/goGo is a tool for managing Go source code.
cmd/gofmtGofmt formats Go programs.
cmd/internal/bioPackage bio implements common I/​O abstractions used within the Go toolchain.
cmd/internal/browserPackage browser provides utilities for interacting with users' browsers.
cmd/internal/dwarfPackage dwarf generates DWARF debugging information.
cmd/internal/gcprogPackage gcprog implements an encoder for packed GC pointer bitmaps, known as GC programs.
cmd/internal/obj
cmd/internal/obj/arm
cmd/internal/objfilePackage objfile implements portable access to OS-specific executable files.
cmd/internal/obj/mips
cmd/internal/obj/ppc64
cmd/internal/obj/x86
cmd/internal/sys
cmd/linkLink, typically invoked as ``go tool link,'' reads the Go archive or object for a package main, along with its dependencies, and combines them into an executable binary.
cmd/link/internal/amd64
cmd/link/internal/arm
cmd/link/internal/arm64
cmd/link/internal/ld
cmd/link/internal/mips64
cmd/link/internal/ppc64
cmd/link/internal/s390x
cmd/link/internal/x86
cmd/nmNm lists the symbols defined or used by an object file, archive, or executable.
cmd/objdumpObjdump disassembles executable files.
cmd/packPack is a simple version of the traditional Unix ar tool.
cmd/pprofPprof interprets and displays profiles of Go programs.
cmd/pprof/internal/svgPackage svg provides tools related to handling of SVG files
cmd/traceTrace is a tool for viewing trace files.
cmd/vetVet examines Go source code and reports suspicious constructs, such as Printf calls whose arguments do not align with the format string.
cmd/vet/internal/cfgThis package constructs a simple control-flow graph (CFG) of the statements and expressions within a single function.
cmd/vet/internal/whitelistPackage whitelist defines exceptions for the vet tool.
compress/bzip2Package bzip2 implements bzip2 decompression.
compress/flatePackage flate implements the DEFLATE compressed data format, described in RFC 1951.
compress/gzipPackage gzip implements reading and writing of gzip format compressed files, as specified in RFC 1952.
compress/lzwPackage lzw implements the Lempel-Ziv-Welch compressed data format, described in T.
compress/zlibPackage zlib implements reading and writing of zlib format compressed data, as specified in RFC 1950.
container/heapPackage heap provides heap operations for any type that implements heap.Interface.
container/listPackage list implements a doubly linked list.
container/ringPackage ring implements operations on circular lists.
contextPackage context defines the Context type, which carries deadlines, cancelation signals, and other request-scoped values across API boundaries and between processes.
cryptoPackage crypto collects common cryptographic constants.
crypto/aesPackage aes implements AES encryption (formerly Rijndael), as defined in U.S.
crypto/cipherPackage cipher implements standard block cipher modes that can be wrapped around low-level block cipher implementations.
crypto/desPackage des implements the Data Encryption Standard (DES) and the Triple Data Encryption Algorithm (TDEA) as defined in U.S.
crypto/dsaPackage dsa implements the Digital Signature Algorithm, as defined in FIPS 186-3.
crypto/ecdsaPackage ecdsa implements the Elliptic Curve Digital Signature Algorithm, as defined in FIPS 186-3.
crypto/ellipticPackage elliptic implements several standard elliptic curves over prime fields.
crypto/hmacPackage hmac implements the Keyed-Hash Message Authentication Code (HMAC) as defined in U.S.
crypto/internal/cipherhwPackage cipherhw exposes common functions for detecting whether hardware support for certain ciphers and authenticators is present.
crypto/md5Package md5 implements the MD5 hash algorithm as defined in RFC 1321.
crypto/randPackage rand implements a cryptographically secure pseudorandom number generator.
crypto/rc4Package rc4 implements RC4 encryption, as defined in Bruce Schneier's Applied Cryptography.
crypto/rsaPackage rsa implements RSA encryption as specified in PKCS#1.
crypto/sha1Package sha1 implements the SHA1 hash algorithm as defined in RFC 3174.
crypto/sha256Package sha256 implements the SHA224 and SHA256 hash algorithms as defined in FIPS 180-4.
crypto/sha512Package sha512 implements the SHA-384, SHA-512, SHA-512/​224, and SHA-512/​256 hash algorithms as defined in FIPS 180-4.
crypto/subtlePackage subtle implements functions that are often useful in cryptographic code but require careful thought to use correctly.
crypto/tlsPackage tls partially implements TLS 1.2, as specified in RFC 5246.
crypto/x509Package x509 parses X.509-encoded keys and certificates.
crypto/x509/pkixPackage pkix contains shared, low level structures used for ASN.1 parsing and serialization of X.509 certificates, CRL and OCSP.
database/sqlPackage sql provides a generic interface around SQL (or SQL-like) databases.
database/sql/driverPackage driver defines interfaces to be implemented by database drivers as used by package sql.
debug/dwarfPackage dwarf provides access to DWARF debugging information loaded from executable files, as defined in the DWARF 2.0 Standard at http:/​/​dwarfstd.org/​doc/​dwarf-2.0.0.pdf
debug/elfPackage elf implements access to ELF object files.
debug/gosymPackage gosym implements access to the Go symbol and line number tables embedded in Go binaries generated by the gc compilers.
debug/machoPackage macho implements access to Mach-O object files.
debug/pePackage pe implements access to PE (Microsoft Windows Portable Executable) files.
debug/plan9objPackage plan9obj implements access to Plan 9 a.out object files.
encodingPackage encoding defines interfaces shared by other packages that convert data to and from byte-level and textual representations.
encoding/ascii85Package ascii85 implements the ascii85 data encoding as used in the btoa tool and Adobe's PostScript and PDF document formats.
encoding/asn1Package asn1 implements parsing of DER-encoded ASN.1 data structures, as defined in ITU-T Rec X.690.
encoding/base32Package base32 implements base32 encoding as specified by RFC 4648.
encoding/base64Package base64 implements base64 encoding as specified by RFC 4648.
encoding/binaryPackage binary implements simple translation between numbers and byte sequences and encoding and decoding of varints.
encoding/csvPackage csv reads and writes comma-separated values (CSV) files.
encoding/gobPackage gob manages streams of gobs - binary values exchanged between an Encoder (transmitter) and a Decoder (receiver).
encoding/hexPackage hex implements hexadecimal encoding and decoding.
encoding/jsonPackage json implements encoding and decoding of JSON as defined in RFC 4627.
encoding/pemPackage pem implements the PEM data encoding, which originated in Privacy Enhanced Mail.
encoding/xmlPackage xml implements a simple XML 1.0 parser that understands XML name spaces.
errorsPackage errors implements functions to manipulate errors.
expvarPackage expvar provides a standardized interface to public variables, such as operation counters in servers.
flagPackage flag implements command-line flag parsing.
fmtPackage fmt implements formatted I/​O with functions analogous to C's printf and scanf.
go/astPackage ast declares the types used to represent syntax trees for Go packages.
go/buildPackage build gathers information about Go packages.
go/constantPackage constant implements Values representing untyped Go constants and their corresponding operations.
go/docPackage doc extracts source code documentation from a Go AST.
go/formatPackage format implements standard formatting of Go source.
go/importerPackage importer provides access to export data importers.
go/internal/gccgoimporterPackage gccgoimporter implements Import for gccgo-generated object files.
go/internal/gcimporterPackage gcimporter implements Import for gc-generated object files.
go/parserPackage parser implements a parser for Go source files.
go/printerPackage printer implements printing of AST nodes.
go/scannerPackage scanner implements a scanner for Go source text.
go/tokenPackage token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates).
go/typesPackage types declares the data types and implements the algorithms for type-checking of Go packages.
hashPackage hash provides interfaces for hash functions.
hash/adler32Package adler32 implements the Adler-32 checksum.
hash/crc32Package crc32 implements the 32-bit cyclic redundancy check, or CRC-32, checksum.
hash/crc64Package crc64 implements the 64-bit cyclic redundancy check, or CRC-64, checksum.
hash/fnvPackage fnv implements FNV-1 and FNV-1a, non-cryptographic hash functions created by Glenn Fowler, Landon Curt Noll, and Phong Vo.
htmlPackage html provides functions for escaping and unescaping HTML text.
html/templatePackage template (html/​template) implements data-driven templates for generating HTML output safe against code injection.
imagePackage image implements a basic 2-D image library.
image/colorPackage color implements a basic color library.
image/color/palettePackage palette provides standard color palettes.
image/drawPackage draw provides image composition functions.
image/gifPackage gif implements a GIF image decoder and encoder.
image/internal/imageutilPackage imageutil contains code shared by image-related packages.
image/jpegPackage jpeg implements a JPEG image decoder and encoder.
image/pngPackage png implements a PNG image decoder and encoder.
index/suffixarrayPackage suffixarray implements substring search in logarithmic time using an in-memory suffix array.
internal/nettracePackage nettrace contains internal hooks for tracing activity in the net package.
internal/pprof/profilePackage profile provides a representation of profile.proto and methods to encode/​decode profiles in this format.
internal/racePackage race contains helper functions for manually instrumenting code for the race detector.
internal/singleflightPackage singleflight provides a duplicate function call suppression mechanism.
internal/syscall/windows
internal/syscall/windows/registryPackage registry provides access to the Windows registry.
internal/syscall/windows/sysdllPackage sysdll is an internal leaf package that records and reports which Windows DLL names are used by Go itself.
internal/testenvPackage testenv provides information about what functionality is available in different testing environments run by the Go team.
internal/trace
ioPackage io provides basic interfaces to I/​O primitives.
io/ioutilPackage ioutil implements some I/​O utility functions.
logPackage log implements a simple logging package.
log/syslogPackage syslog provides a simple interface to the system log service.
mathPackage math provides basic constants and mathematical functions.
math/bigPackage big implements arbitrary-precision arithmetic (big numbers).
math/cmplxPackage cmplx provides basic constants and mathematical functions for complex numbers.
math/randPackage rand implements pseudo-random number generators.
mimePackage mime implements parts of the MIME spec.
mime/multipartPackage multipart implements MIME multipart parsing, as defined in RFC 2046.
mime/quotedprintablePackage quotedprintable implements quoted-printable encoding as specified by RFC 2045.
netPackage net provides a portable interface for network I/​O, including TCP/​IP, UDP, domain name resolution, and Unix domain sockets.
net/httpPackage http provides HTTP client and server implementations.
net/http/cgiPackage cgi implements CGI (Common Gateway Interface) as specified in RFC 3875.
net/http/cookiejarPackage cookiejar implements an in-memory RFC 6265-compliant http.CookieJar.
net/http/fcgiPackage fcgi implements the FastCGI protocol.
net/http/httptestPackage httptest provides utilities for HTTP testing.
net/http/httptracePackage httptrace provides mechanisms to trace the events within HTTP client requests.
net/http/httputilPackage httputil provides HTTP utility functions, complementing the more common ones in the net/​http package.
net/http/internalPackage internal contains HTTP internals shared by net/​http and net/​http/​httputil.
net/http/pprofPackage pprof serves via its HTTP server runtime profiling data in the format expected by the pprof visualization tool.
net/internal/socktestPackage socktest provides utilities for socket testing.
net/mailPackage mail implements parsing of mail messages.
net/rpcPackage rpc provides access to the exported methods of an object across a network or other I/​O connection.
net/rpc/jsonrpcPackage jsonrpc implements a JSON-RPC ClientCodec and ServerCodec for the rpc package.
net/smtpPackage smtp implements the Simple Mail Transfer Protocol as defined in RFC 5321.
net/textprotoPackage textproto implements generic support for text-based request/​response protocols in the style of HTTP, NNTP, and SMTP.
net/urlPackage url parses URLs and implements query escaping.
osPackage os provides a platform-independent interface to operating system functionality.
os/execPackage exec runs external commands.
os/signalPackage signal implements access to incoming signals.
os/userPackage user allows user account lookups by name or id.
pathPackage path implements utility routines for manipulating slash-separated paths.
path/filepathPackage filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths.
pluginPackage plugin implements loading and symbol resolution of Go plugins.
reflectPackage reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types.
regexpPackage regexp implements regular expression search.
regexp/syntaxPackage syntax parses regular expressions into parse trees and compiles parse trees into programs.
runtimePackage runtime contains operations that interact with Go's runtime system, such as functions to control goroutines.
runtime/cgoPackage cgo contains runtime support for code generated by the cgo tool.
runtime/debugPackage debug contains facilities for programs to debug themselves while they are running.
runtime/internal/atomic
runtime/internal/syspackage sys contains system- and configuration- and architecture-specific constants used by the runtime.
runtime/pprofPackage pprof writes runtime profiling data in the format expected by the pprof visualization tool.
runtime/racePackage race implements data race detection logic.
runtime/traceGo execution tracer.
sortPackage sort provides primitives for sorting slices and user-defined collections.
strconvPackage strconv implements conversions to and from string representations of basic data types.
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.
syncPackage sync provides basic synchronization primitives such as mutual exclusion locks.
sync/atomicPackage atomic provides low-level atomic memory primitives useful for implementing synchronization algorithms.
syscallPackage syscall contains an interface to the low-level operating system primitives.
testingPackage testing provides support for automated testing of Go packages.
testing/iotestPackage iotest implements Readers and Writers useful mainly for testing.
testing/quickPackage quick implements utility functions to help with black box testing.
text/scannerPackage scanner provides a scanner and tokenizer for UTF-8-encoded text.
text/tabwriterPackage tabwriter implements a write filter (tabwriter.Writer) that translates tabbed columns in input into properly aligned text.
text/templatePackage template implements data-driven templates for generating textual output.
text/template/parsePackage parse builds parse trees for templates as defined by text/​template and html/​template.
timePackage time provides functionality for measuring and displaying time.
unicodePackage unicode provides data and functions to test some properties of Unicode code points.
unicode/utf16Package utf16 implements encoding and decoding of UTF-16 sequences.
unicode/utf8Package utf8 implements functions and constants to support text encoded in UTF-8.
unsafePackage unsafe contains operations that step around the type safety of Go programs.
vendor/golang_org/x/net/lex/httplexPackage httplex contains rules around lexical matters of various HTTP-related specifications.
vendor/golang_org/x/net/routePackage route provides basic functions for the manipulation of packet routing facilities on BSD variants.

View the official documentation at golang.org.