kegg3 logo  KEGG WebLinks

This is an introductory document for retrieving html files from and creating links to KEGG at https://www.kegg.jp/.

General form

REST-style URL 
https://www.kegg.jp/<operation>/<argument>

<operation> = entry | pathway | brite | module | network | genome
Database name 
<database> = KEGG databases (Table 1) and KEGG databases in Japanese (Table 2)

           = pathway | brite | module | ko | <org> | vg | vp | ag | genome | compound |
             glycan | reaction | rclass | enzyme | network | variant | disease |
             drug | dgroup | <medicus>

<org> = Three or four-letter KEGG organism code

<medicus> = disease_ja | drug_ja | dgroup_ja | compound_ja
Database entry identifier 
<keggid> = <prefix><number> | <database>:<entry>

<prefix> = Database dependent prefix shown in Table 1
<number> = Five-digit number
<entry> = Entry name or accession number

<keggids> = <keggid>1[+<keggid>2...]
(Note)
The base URL www.kegg.jp may be replaced by www.genome.jp for the entry operation.

KEGG ID naming conventions

KEGG is an integrated database consisting of sixteen databases shown in Table 1. Each entry is uniquely identified by the KEGG identifier (KEGG ID), which takes the form of <database>:<entry>. In most cases <database> may be omitted, because <entry> takes the form of a database-dependent prefix followed by a five-digit number.

Table 1. KEGG databases

DB name Prefix KEGG ID Content Web page
pathway map, <org>
ko, ec, rn		 <map number> KEGG pathway maps KEGG PATHWAY
brite br, jp
ko, <org>		 <br number> BRITE functional hierarchies KEGG BRITE
module M, <org>_M <M number> KEGG modules KEGG MODULE
ko K <K number> KO functional orthologs KEGG ORTHOLOGY
genes <org>:<gene>
vg:<gene>
vp:<gene-no>
ag:<protein>		 Genes in KEGG organisms
Genes in viruses category
Mature peptides in viruses
Genes in addendum category		 KEGG GENES
genome T <T number>, gn:<org>
gn:<vtax>		 KEGG organisms KEGG GENOME
compound C <C number> Small molecules KEGG COMPOUND
glycan G <G number> Glycans KEGG GLYCAN
reaction R <R number> Biochemical reactions KEGG REACTION
rclass RC <RC number> Reaction class
enzyme ec:<ecnum> Enzyme nomenclature KEGG ENZYME
network nt
N		 <ne number>
<N number>		 Network variation maps
Network elements		 KEGG NETWORK
variant hsa_var:<gene_vno> Human gene variants
disease H <H number> Human diseases KEGG DISEASE
drug D <D number> Drugs KEGG DRUG
dgroup DG <DG number> Drug groups
<org>
<gene>
<gene-no>
<protein>		 three- or four-letter KEGG organism code
NCBI gene ID or locus_tag
Gene ID followed by peptide number
NCBI protein ID		 <vtax>
<ecnum>
<gene-vno>		 NCBI virus taxonomy ID
EC number
Gene ID followed by variant number

Table 2 shows Japanese version of selected KEGG databases.

Table 2. KEGG databases in Japanese

DB name KEGG ID Web page
disease_ja ds_ja:<H number> KEGG DISEASE (in Japanese)
drug_ja dr_ja:<D number> KEGG DRUG (in Japanese)
dgroup_ja dg_ja:<DG number>
compound_ja cpd_ja:<C number>

ENTRY

Name
entry – retrieve database entries
URL form 
https://www.kegg.jp/entry/<keggids>

<keggids> = KEGG IDs of the following <database>
<database> = pathway | brite | module | ko | <org> | vg | ag | genome | compound |
             glycan | reaction | rclass | enzyme | network | variant | disease |
             drug | dgroup | <medicus>
Description
This URL returns the KEGG database entry page(s). It is equivalent to:
    https://www.kegg.jp/dbget-bin/www_bget?<keggids>
<keggids> may contain up to 10 entries.
Examples
https://www.kegg.jp/entry/K00873
https://www.kegg.jp/entry/C00022
https://www.kegg.jp/entry/map00010
https://www.kegg.jp/entry/br:01002
See also
KEGG API get operation for obtaining database entries in flat-file text format.

PATHWAY

Name
pathway - display pathway map
URL form 
https://www.kegg.jp/pathway/<mapid>

<mapid> = KEGG pathway map identifier (map number)
Description
This URL returns the KEGG pathway map page. It is equivalent to:
    https://www.kegg.jp/kegg-bin/show_pathway?<mapid>
Examples
https://www.kegg.jp/pathway/map00010
https://www.kegg.jp/pathway/hsa00010
See also
Pathway viewer in KEGG Web Apps.

BRITE

Name
brite - display brite hierarchy
URL form 
https://www.kegg.jp/brite/<brid>

<brid> = KEGG brite hierarchy identifier (br number)
Description
This URL returns the KEGG BRITE hierarchy page. It is equivalent to:
    https://www.kegg.jp/kegg-bin/show_brite?<brid>
Examples
https://www.kegg.jp/brite/ko00001
https://www.kegg.jp/brite/br08303
Restriction
Organism-specific brite hierarchy, i.e., organism-code prefixed br number, is not accepted. Use ko prefixed br number and to obtain an organism-specifc version.
See also
Brite viewer in KEGG Web Apps.

MODULE

URL form
module - display module diagram
URL form 
https://www.kegg.jp/kegg-bin/show_module?<modid>

<modid> = KEGG module identifier (M number)
Description
This URL returns the KEGG module page. It is equivalent to:
    https://www.kegg.jp/kegg-bin/show_module?<modid>
Examples
https://www.kegg.jp/module/M00010
Restriction
Organism-specific module identifier is not accepted. Use reference M number and to obtain an organism-specifc version.

NETWORK

URL form
network - display network variation map with optional marking of objects
URL form 
https://www.kegg.jp/network/<ntid>[+<nt_objects>]

<ntid> = KEGG network variation map identifier (nt number)
<nt_objects> = <keggid>1[+<keggid>2...]
Description
This URL returns the KEGG network variation map page. It is equivalent to:
    https://www.kegg.jp/kegg-bin/show_network?<ntid>[+<nt_objects>]
Examples
https://www.kegg.jp/network/nt06210
https://www.kegg.jp/network/nt06010+D07130

GENOME

Name
genome - launch KEGG genome browser with optional gene specification
URL form 
https://www.kegg.jp/genome/<gnid>[+<gene>]

<gnid> = KEGG genome identifier (T number or KEGG organism code)
<gene> = Gene entry identifier
Description
This URL returns the KEGG GENOME browser page. It is equivalent to:
    https://www.kegg.jp/kegg-bin/show_genome?<gnid>[+<gene>]
Examples
https://www.kegg.jp/genome/T00007
https://www.kegg.jp/genome/T01001+59272
https://www.kegg.jp/genome/hsa+59272
See also
Genome browser in KEGG Web Apps.

Last updated: May 26, 2025

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