JSON-LD is a set of W3C standards track specifications for representing Linked Data in JSON. It is fully compatible with the RDF data model, but allows developers to work with data entirely within JSON. More information on JSON-LD can be found at http://json-ld.org/

1. JSON-LD
JSON for Linked Data
Gregg Kellogg
gregg@greggkellogg.net
@gkellogg

2. JSON-LD
JSON for Linked Data
nk ing
Li
Gregg Kellogg
gregg@greggkellogg.net
@gkellogg

3. JSON
JSON has taken over service APIs

4. Tower of Babel

5. Tower of Babel
GitHub
{
"type": "User",
"followers": 35,
"html_url": "https://github.com/gkellogg",
"hireable": true,
"created_at": "2009-01-13T16:58:46Z",
"public_repos": 44,
"blog": "http://greggkellogg.net",
"bio": "Gregg is a Standards Architect ...",
"gravatar_id":
"42f948adff3afaa52249d963117af7c8",
"following": 35,
"company": "Self",
"public_gists": 4,
"location": "San Rafael, CA",
"name": "Gregg Kellogg",
"email": "gregg@kellogg-assoc.com",
"url": "https://api.github.com/users/gkellogg",
"avatar_url": "...",
"id": 46296,
"login": "gkellogg"

6. Tower of Babel
GitHub Twitter
{
{ "max_id": 195520745634406400,
"type": "User", "page": 1,
"followers": 35, "query": "%40gkellogg",
"html_url": "https://github.com/gkellogg", "results": [{
"hireable": true, "created_at": "Thu, 26 Apr 2012 14:32:33
"created_at": "2009-01-13T16:58:46Z", +0000",
"public_repos": 44, "from_user": "kendall",
"blog": "http://greggkellogg.net", "from_user_name": "Kendall Clark",
"bio": "Gregg is a Standards Architect ...", "id": 195520745634406400,
"gravatar_id": "in_reply_to_status_id":
"42f948adff3afaa52249d963117af7c8", 195518881811529729,
"following": 35, "iso_language_code": "en",
"company": "Self", "metadata": {"result_type": "recent"},
"public_gists": 4, "text": "@Gkellogg Multiple resources in a
"location": "San Rafael, CA", single JSON-LD struct/doc/message.",
"name": "Gregg Kellogg", "to_user": "Gkellogg",
"email": "gregg@kellogg-assoc.com", "to_user_id": 6125262,
"url": "https://api.github.com/users/gkellogg", "to_user_name": "Gregg Kellogg"
"avatar_url": "...", }],
"id": 46296, "results_per_page": 1,
"login": "gkellogg" "since_id": 0,
"since_id_str": "0"
}

7. Tower of Babel
GitHub Twitter Facebook
{
{ "max_id": 195520745634406400, {
"type": "User", "page": 1, "id": "1236600216",
"followers": 35, "query": "%40gkellogg", "name": "Gregg Kellogg",
"html_url": "https://github.com/gkellogg", "results": [{ "first_name": "Gregg",
"hireable": true, "created_at": "Thu, 26 Apr 2012 14:32:33 "last_name": "Kellogg",
"created_at": "2009-01-13T16:58:46Z", +0000", "link": "https://www.facebook.com/
"public_repos": 44, "from_user": "kendall", gkellogg",
"blog": "http://greggkellogg.net", "from_user_name": "Kendall Clark", "username": "gkellogg",
"bio": "Gregg is a Standards Architect ...", "id": 195520745634406400, "gender": "male",
"gravatar_id": "in_reply_to_status_id": "locale": "en_US"
"42f948adff3afaa52249d963117af7c8", 195518881811529729, }
"following": 35, "iso_language_code": "en",
"company": "Self", "metadata": {"result_type": "recent"},
"public_gists": 4, "text": "@Gkellogg Multiple resources in a
"location": "San Rafael, CA", single JSON-LD struct/doc/message.",
"name": "Gregg Kellogg", "to_user": "Gkellogg",
"email": "gregg@kellogg-assoc.com", "to_user_id": 6125262,
"url": "https://api.github.com/users/gkellogg", "to_user_name": "Gregg Kellogg"
"avatar_url": "...", }],
"id": 46296, "results_per_page": 1,
"login": "gkellogg" "since_id": 0,
"since_id_str": "0"
}

8. Introducing JSON-LD
@graph
@context
@id
JSON-based syntax to express linked data
@language
@value
@list
@type @set

9. Self-describing Messages
• Give objects types {
"@context": {
(@type) "schema": "http://schema.org/",
"Person": "schema:Person",
"colleagues": {"@id": "schema:colleagues", "@type": "@id"},
"name": "schema:name",
"image": {"@id": "schema:image", "@type": "@id"},
"url": {"@id": "schema:url", "@type": "@id"}
}
}
{
"@context": "http://example.com/context.jsonld",
"@type": "Person",
"image": "http://localhost:9393/examples/schema.org/janedoe.jpg",
"colleagues": [
"http://www.xyz.edu/students/alicejones.html",
"http://www.xyz.edu/students/bobsmith.html"
],
"name": "Jane Doe",
"url": "http://www.janedoe.com"
}

10. Self-describing Messages
• Give objects types {
"@context": {
(@type) "schema": "http://schema.org/",
"Person": "schema:Person",
•
"colleagues": {"@id": "schema:colleagues", "@type": "@id"},
Associate properties "name": "schema:name",
"image": {"@id": "schema:image", "@type": "@id"},
with IRIs "url": {"@id": "schema:url", "@type": "@id"}
}
}
{
"@context": "http://example.com/context.jsonld",
"@type": "Person",
"image": "http://localhost:9393/examples/schema.org/janedoe.jpg",
"colleagues": [
"http://www.xyz.edu/students/alicejones.html",
"http://www.xyz.edu/students/bobsmith.html"
],
"name": "Jane Doe",
"url": "http://www.janedoe.com"
}

11. Self-describing Messages
• Give objects types {
"@context": {
(@type) "schema": "http://schema.org/",
"Person": "schema:Person",
•
"colleagues": {"@id": "schema:colleagues", "@type": "@id"},
Associate properties "name": "schema:name",
"image": {"@id": "schema:image", "@type": "@id"},
with IRIs "url": {"@id": "schema:url", "@type": "@id"}
}
•
}
Use terms defined in a
referenced context {
"@context": "http://example.com/context.jsonld",
"@type": "Person",
"image": "http://localhost:9393/examples/schema.org/janedoe.jpg",
"colleagues": [
"http://www.xyz.edu/students/alicejones.html",
"http://www.xyz.edu/students/bobsmith.html"
],
"name": "Jane Doe",
"url": "http://www.janedoe.com"
}

12. Self-describing Messages
• Give objects types {
"@context": {
(@type) "schema": "http://schema.org/",
"Person": "schema:Person",
•
"colleagues": {"@id": "schema:colleagues", "@type": "@id"},
Associate properties "name": "schema:name",
"image": {"@id": "schema:image", "@type": "@id"},
with IRIs "url": {"@id": "schema:url", "@type": "@id"}
}
•
}
Use terms defined in a
referenced context {
"@context": "http://example.com/context.jsonld",
"@type": "Person",
• Specify property types
"image": "http://localhost:9393/examples/schema.org/janedoe.jpg",
"knows": [
"http://www.xyz.edu/students/alicejones.html",
in context "http://www.xyz.edu/students/bobsmith.html"
],
"name": "Jane Doe",
"url": "http://www.janedoe.com"
}

13. Language Principles

14. • Make full use of JSON syntactic
{
"@context": "http://json-ld.org/contexts/person",
representations "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
• Object defines a subject "name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
definition }

15. • Make full use of JSON syntactic
{
"@context": "http://json-ld.org/contexts/person",
representations "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
• Object defines a subject "name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
definition }
• Also used for subject
reference and value { "@id": "http://greggkellogg.net/foaf#me" }
representations

16. • Make full use of JSON syntactic
{
"@context": "http://json-ld.org/contexts/person",
representations "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
• Object defines a subject "name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
definition }
• Also used for subject
reference and value { "@id": "http://greggkellogg.net/foaf#me" }
representations
{
"@type": "Recipe",
"name": "Mom's World Famous Banana Bread",
"ingredients": [
• Arrays describe sets of unordered
values
"3 or 4 ripe bananas, smashed",
"1 egg",
"3/4 cup of sugar"
],
• Single values can skip array "nutrition": [{
"@type": ["NutritionInformation"],
"calories": ["240 calories"],
"fatContent": ["9 grams fat"]
}]
}

17. • Define terms to use short {
"@id": "http://greggkellogg.net/foaf#me",
property names "@type": "http://schema.org/Person",
"http://schema.org/name": "Gregg Kellogg",
• Convenient for JavaScript “.” "http://schema.org/knows": {
"@id": "http://www.markus-lanthaler.com/"
notation }
}
{
"@context": {
"Person": "http://schema.org/Person",
"name": "http://schema.org/name",
"knows”: "http://schema.org/knows"
},
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {"@id": "http://www.markus-lanthaler.com/"}
}

18. • Define terms to use short {
"@id": "http://greggkellogg.net/foaf#me",
property names "@type": "http://schema.org/Person",
"http://schema.org/name": "Gregg Kellogg",
• Convenient for JavaScript “.” "http://schema.org/knows": {
"@id": "http://www.markus-lanthaler.com/"
notation }
}
• Add @type coercions to
use simple string value.
{
"@context": {
"schema": "http://schema.org/",
"Person": "schema:Person",
"name": "schema:name",
"knows”: {
"@id": "schema:knows",
"@type": "@id"
},
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
}

19. • Define terms to use short {
"@id": "http://greggkellogg.net/foaf#me",
property names "@type": "http://schema.org/Person",
"http://schema.org/name": "Gregg Kellogg",
• Convenient for JavaScript “.” "http://schema.org/knows": {
"@id": "http://www.markus-lanthaler.com/"
notation }
}
• Add @type coercions to
use simple string value.
{
"@context": {
"schema": "http://schema.org/",
"Person": "schema:Person",
• Use external @context. "name": "schema:name",
"knows”: {
"@id": "schema:knows",
"@type": "@id"
}
}
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
}

20. •
{
Define referenced subject "@context": "http://json-ld.org/contexts/person",
definition with chaining "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}

21. •
{
Define referenced subject "@context": "http://json-ld.org/contexts/person",
definition with chaining "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
• Add @language to values. "@type": "Person",
"name": "Gregg Kellogg",
"honorificSuffix": {"@value": "M.S.", "@language": "en"},
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"honorificSuffix": {"@value": "Dipl.Ing.", "@language": "de"},
"knows" "http://greggkellogg.net/foaf#me"
}
}

22. • Add @type to values. {
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
• Link to externally defined "@type": "Person",
"name": "Gregg Kellogg",
resources. "birthDate": {"@value": "1957-02-27", "@type": "xsd:date"},
"honorificSuffix": {"@value": "M.S.", "@language": "en"},
"knows": "http://www.markus-lanthaler.com/"
}

23. • Add property @type and {
"@context": {
@language definitions to "schema": "http://schema.org/",
context "Person": "schema:Person",
"name": "schema:name",
"birthDate”: {
"@id": "schema: birthDate","@type": "xsd:date"
},
"honorificSuffix”: {
"@id": "schema:honorificSuffix","@language": "en"
},
"knows”: {"@id": "schema:knows","@type": "@id"}
},
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"birthDate": "1957-02-27",
"honorificSuffix": "M.S.",
"knows": "http://www.markus-lanthaler.com/"
}

24. • More features defined in the syntax
specification*:
• @set, @list, Compact IRIs, Unlabeled
Nodes
• Embedded @context definitions
• Named Graphs
* http://json-ld.org/spec/latest/json-ld-syntax

25. Examples “In the Wild”

26. DBpedia
{
"@graph": [
{
"@id": "http://dbpedia.org/resource/DBpedia",
"http://dbpedia.org/property/genre" : [ "http://dbpedia.org/resource/Linked_Data" ]
},
{
"@id": "http://dbpedia.org/resource/Linked_Data",
"@type" : [ "http://dbpedia.org/class/yago/Buzzwords" ] ,
"http://www.w3.org/2002/07/owl#sameAs" : ["http://rdf.freebase.com/ns/m/02r2kb1"] ,
"http://www.w3.org/2000/01/rdf-schema#comment": [
{ "@value" : "Linked Open Data (LOD) bezeichnet ..." , "@language" : "de" } ,
{ "@value" : "In computing, linked Data describes ..." , "@language" : "en" } ],
"http://purl.org/dc/terms/subject" : [
"http://dbpedia.org/resource/Category:World_Wide_Web" ,
"http://dbpedia.org/resource/Category:Buzzwords" ,
"http://dbpedia.org/resource/Category:Semantic_Web"
],
...
}]
}
http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=DESCRIBE+<http://dbpedia.org/resource/
Linked_Data>&output=application%2Fld%2Bjson

27. Schema.org
Using RDFa to JSON-LD bookmarklet*
http://linter.structured-data.org/examples/
schema.org/sdo_eg_rdfa_12.html
* bookmarklet courtesy of Niklas Lindström

28. Schema.org
{
"@context": {...},
Using RDFa to JSON-LD bookmarklet* "@graph": [{
"@id": "http://linter.structured-data.org/examples/schema.org/Recipe.rdfa",
"rdfa:usesVocabulary": "http://schema.org/"
}, {
"@type": ["Recipe"],
"name": ["Mom's World Famous Banana Bread"],
"author": ["John Smith"],
"publishDate": ["2009-05-08"],
"image": [{"@id": ".../bananabread.jpg"}],
http://linter.structured-data.org/examples/ "description": ["This classic banana bread recipe ..."],
schema.org/sdo_eg_rdfa_12.html "prepTime": ["PT15M"],
"cookTime": ["PT1H"],
"recipeYield": ["1 loaf"],
"nutrition": [{
"@type": ["NutritionInformation"],
"calories": ["240 calories"],
"fatContent": ["9 grams fat"]
}],
"ingredients": [
"3 or 4 ripe bananas, smashed",
"1 egg",
"3/4 cup of sugar"
],
"recipeInstructions": ["Preheat the oven to 350 degrees..."],
"interactionCount": ["UserComments:140"]
}]
* bookmarklet courtesy of Niklas Lindström
}

29. Drupal
http://directory.occupy.net/node/20080.jsonld

30. Drupal
{
"@context": "http://drupal.example.org/context.jsonld",
"@id": "http://directory.occupy.net/occupation/al/occupy-
prishtina",
"@type": ["ows:Occupation", "schema:Organization"],
"foaf:name": "Occupy Prishtina",
"schema:name": "Occupy Prishtina",
"dc:date": "2012-02-12T21:18:08-05:00",
"dc:created": "2012-02-12T21:18:08-05:00",
"dc:modified": "2012-02-12T21:57:52-05:00",
"sioc:num_replies": 0,
"schema:foundingDate": "2011-10-15T00:00:00-04:00",
"ows:twitter_account": "@OccupyPrishtina",
"foaf:mbox": "",
"schema:telephone": "",
"foaf:phone": ""
}
http://directory.occupy.net/node/20080.jsonld

31. PaySwarm
{
"@context": "http://purl.org/payswarm/v1",
"@graph": {
"@type": "Transaction",
"transfer": {
"@type": "Transfer",
Named "amount": "7.50",
Graph "currency": "USD",
"source": "https://bluebank.com/people/manu/accounts/food",
"destination": "https://redbank.com/people/gregg/accounts/hosting",
"comment": "Chipping in for the Pizza Party tomorrow."
},
},
"signature": {
"@type": "JsonLdSignature",
Signature of "created": "2011-09-23T20:21:34Z",
"signer": "http://bluebank.com/people/manu/keys/5",
Named "signatureValue": "ExMgoDIyOGQzNGVkM...mOWM32Nj4NTIyZTkZDYMI="
Graph }
}

32. Working with data
• Expand documents to remove effect of @context.
{
"@context": "http://drupal.example.org/context.jsonld",
"@id": "http://directory.occupy.net/occupation/al/occupy-
prishtina",
"@type": ["ows:Occupation", "schema:Organization"],
"foaf:name": "Occupy Prishtina",
"schema:name": "Occupy Prishtina",
"dc:date": "2012-02-12T21:18:08-05:00",
"dc:created": "2012-02-12T21:18:08-05:00",
"dc:modified": "2012-02-12T21:57:52-05:00",
"sioc:num_replies": 0,
"schema:foundingDate": "2011-10-15T00:00:00-04:00",
"ows:twitter_account": "@OccupyPrishtina",
"foaf:mbox": "",
"schema:telephone": "",
"foaf:phone": ""
}

33. Working with data
• Expand documents to remove effect of @context.
[{
"@id": "http://directory.occupy.net/occupation/al/occupy-prishtina",
{ "@type": ["http://vocab.occupy.net/ows#Occupation", "http://schema.org/Organization"],
"@context": "http://drupal.example.org/context.jsonld", "http://purl.org/dc/terms/created": [{
"@id": "http://directory.occupy.net/occupation/al/occupy- "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"@value": "2012-02-12T21:18:08-05:00"
prishtina",
}],
"@type": ["ows:Occupation", "schema:Organization"], "http://purl.org/dc/terms/date": [{
"foaf:name": "Occupy Prishtina", "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"schema:name": "Occupy Prishtina", "@value": "2012-02-12T21:18:08-05:00"
}],
"dc:date": "2012-02-12T21:18:08-05:00",
"http://purl.org/dc/terms/modified": [{
"dc:created": "2012-02-12T21:18:08-05:00", "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"dc:modified": "2012-02-12T21:57:52-05:00", "@value": "2012-02-12T21:57:52-05:00"
"sioc:num_replies": 0, }],
"http://rdfs.org/sioc/ns#num_replies": [{
"schema:foundingDate": "2011-10-15T00:00:00-04:00",
"@type": "http://www.w3.org/2001/XMLSchema#integer",
"ows:twitter_account": "@OccupyPrishtina", "@value": "0"
"foaf:mbox": "", }],
"schema:telephone": "", "http://schema.org/foundingDate": [{
"@type": "http://www.w3.org/2001/XMLSchema#date",
"foaf:phone": ""
"@value": "2011-10-15T00:00:00-04:00"
} }],
"http://schema.org/name": ["Occupy Prishtina"],
"http://schema.org/telephone": [""],
"http://vocab.occupy.net/ows#twitter_account": ["@OccupyPrishtina"],
"http://xmlns.com/foaf/0.1/mbox": [""],
"http://xmlns.com/foaf/0.1/name": ["Occupy Prishtina"],
"http://xmlns.com/foaf/0.1/phone": [""]
}]

34. Working with data
• Compact documents to apply a @context.
[{
"@id": "http://directory.occupy.net/occupation/al/occupy-prishtina",
"@type": ["http://vocab.occupy.net/ows#Occupation", "http://schema.org/Organization"],
"http://purl.org/dc/terms/created": [{
"@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"@value": "2012-02-12T21:18:08-05:00"
}],
"http://purl.org/dc/terms/date": [{
"@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"@value": "2012-02-12T21:18:08-05:00"
}],
"http://purl.org/dc/terms/modified": [{
"@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"@value": "2012-02-12T21:57:52-05:00"
}],
"http://rdfs.org/sioc/ns#num_replies": [{
"@type": "http://www.w3.org/2001/XMLSchema#integer",
"@value": "0"
}],
"http://schema.org/foundingDate": [{
"@type": "http://www.w3.org/2001/XMLSchema#date",
"@value": "2011-10-15T00:00:00-04:00"
}],
"http://schema.org/name": ["Occupy Prishtina"],
"http://schema.org/telephone": [""],
"http://vocab.occupy.net/ows#twitter_account": ["@OccupyPrishtina"],
"http://xmlns.com/foaf/0.1/mbox": [""],
"http://xmlns.com/foaf/0.1/name": ["Occupy Prishtina"],
"http://xmlns.com/foaf/0.1/phone": [""]
}]

35. Working with data
• Compact documents to apply a @context.
[{
"@id": "http://directory.occupy.net/occupation/al/occupy-prishtina",
{
"@type": ["http://vocab.occupy.net/ows#Occupation", "http://schema.org/Organization"], "@context": "http://drupal.example.org/context.jsonld",
"http://purl.org/dc/terms/created": [{ "@id": "http://directory.occupy.net/occupation/al/occupy-
"@type": "http://www.w3.org/2001/XMLSchema#dateTime", prishtina",
"@value": "2012-02-12T21:18:08-05:00" "@type": ["ows:Occupation", "schema:Organization"],
}],
"http://purl.org/dc/terms/date": [{ "foaf:name": "Occupy Prishtina",
"@type": "http://www.w3.org/2001/XMLSchema#dateTime", "schema:name": "Occupy Prishtina",
"@value": "2012-02-12T21:18:08-05:00" "dc:date": "2012-02-12T21:18:08-05:00",
}], "dc:created": "2012-02-12T21:18:08-05:00",
"http://purl.org/dc/terms/modified": [{
"@type": "http://www.w3.org/2001/XMLSchema#dateTime", "dc:modified": "2012-02-12T21:57:52-05:00",
"@value": "2012-02-12T21:57:52-05:00" "sioc:num_replies": 0,
}], "schema:foundingDate": "2011-10-15T00:00:00-04:00",
"http://rdfs.org/sioc/ns#num_replies": [{ "ows:twitter_account": "@OccupyPrishtina",
"@type": "http://www.w3.org/2001/XMLSchema#integer",
"@value": "0" "foaf:mbox": "",
}], "schema:telephone": "",
"http://schema.org/foundingDate": [{ "foaf:phone": ""
"@type": "http://www.w3.org/2001/XMLSchema#date", }
"@value": "2011-10-15T00:00:00-04:00"
}],
"http://schema.org/name": ["Occupy Prishtina"],
"http://schema.org/telephone": [""],
"http://vocab.occupy.net/ows#twitter_account": ["@OccupyPrishtina"],
"http://xmlns.com/foaf/0.1/mbox": [""],
"http://xmlns.com/foaf/0.1/name": ["Occupy Prishtina"],
"http://xmlns.com/foaf/0.1/phone": [""]
}]

36. Working with data
• Frame documents to impose structure
input
{
"@context": {
"dc": "http://purl.org/dc/elements/1.1/",
"ex": "http://example.org/vocab#",
"contains": {"@type": "@id"}
},
"@graph": [{
"@id": "http://example.org/test/#library",
"@type": "ex:Library",
"ex:contains": "http://example.org/test#book"
}, {
"@id": "http://example.org/test#book",
"@type": "ex:Book",
"dc:contributor": "Writer",
"dc:title": "My Book",
"ex:contains": "http://example.org/test#chapter"
}, {
"@id": "http://example.org/test#chapter",
"@type": "ex:Chapter",
"dc:description": "Fun",
"dc:title": "Chapter One"
}]
}

37. Working with data
• Frame documents to impose structure
input frame
{ {
"@context": { "@context": {
"dc": "http://purl.org/dc/elements/1.1/", "dc": "http://purl.org/dc/elements/1.1/",
"ex": "http://example.org/vocab#", "ex": "http://example.org/vocab#",
"contains": {"@type": "@id"} "contains": {“@id”: “ex:contains”, "@type": "@id",
}, “title”: “dc:title”
"@graph": [{ },
"@id": "http://example.org/test/#library", "@type": "ex:Library",
+
"@type": "ex:Library", "contains": {
"ex:contains": "http://example.org/test#book" "@type": "ex:Book",
}, { "contains": {
"@id": "http://example.org/test#book", "@type": "ex:Chapter"
"@type": "ex:Book", }
"dc:contributor": "Writer", }
"dc:title": "My Book", }
"ex:contains": "http://example.org/test#chapter"
}, {
"@id": "http://example.org/test#chapter",
"@type": "ex:Chapter",
"dc:description": "Fun",
"dc:title": "Chapter One"
}]
}

38. Working with data
• Frame documents to impose structure
input frame output
{ {
{
"@context": { "@context": {
"@context": {
"dc": "http://purl.org/dc/elements/1.1/", "dc": "http://purl.org/dc/elements/1.1/",
"dc": "http://purl.org/dc/elements/1.1/",
"ex": "http://example.org/vocab#", "ex": "http://example.org/vocab#",,
"ex": "http://example.org/vocab#",
"contains": {“@id”: “ex:contains”, "@type": "@id", "contains": {“@id”: “ex:contains”, "@type": "@id"
"contains": {"@type": "@id"}
“title”: “dc:title” “title”: “dc:title”
},
}, },
"@graph": [{
"@type": "ex:Library", "@graph": [{
"@id": "http://example.org/test/#library", "@id": "http://example.org/test/#library",
+
"@type": "ex:Library", "contains": {
"@type": "ex:Book", "@type": "ex:Library",
"ex:contains": "http://example.org/test#book"
"contains": { "contains": {
}, {
"@type": "ex:Chapter" "@id": "http://example.org/test#book",
"@id": "http://example.org/test#book",
} "@type": "ex:Book",
"@type": "ex:Book",
} "dc:contributor": "Writer",
"dc:contributor": "Writer",
} "title": "My Book",
"dc:title": "My Book", "contains": {
"ex:contains": "http://example.org/test#chapter" "@id": "http://example.org/test#chapter",
}, { "@type": "ex:Chapter",
"@id": "http://example.org/test#chapter", "dc:description": "Fun",
"@type": "ex:Chapter", "title": "Chapter One"
"dc:description": "Fun", }
"dc:title": "Chapter One" }
}] }]
} }
JavaScript object path: data[‘@graph][0].contains.contains.title

39. Retrofit existing APIs
GET /foaf.json HTTP/1.1
Host: greggkellogg.net
Accept: application/json,*/*;q=0.1
====================================
HTTP/1.0 200 OK
...
Content-Type: application/json
Link: <http://json-ld.org/contexts/person>; rel="describedby"; type="application/ld+json"
{
"name": "Gregg Kellogg",
"homepage": "http://greggkellogg.net/",
"depiction": "http://twitter.com/account/profile_image/gkellogg"
}

40. Macros
• Transform information
{
"type": "User",
• Add @id to data
"followers": 35,
"name": "Gregg Kellogg",
• Other programmatic
transformations
"email": "gregg@kellogg-assoc.com",
"url": "https://api.github.com/users/
gkellogg",
"avatar_url": "...",
"id": 46296,
"login": "gkellogg"
}
* json-ld-macros courtesy of Antonio Garrote

41. {
Macros
"type": "User",
"followers": 35,
"name": "Gregg Kellogg",
"email": "gregg@kellogg-assoc.com",
• Transform information
"url": "https://api.github.com/users/
gkellogg",
"avatar_url": "...",
"id": 46296,
• Add @id to data
}
"login": "gkellogg"
• Other programmatic
transformations
* json-ld-macros courtesy of Antonio Garrote

42. {
Macros
"type": "User",
"followers": 35,
"name": "Gregg Kellogg",
"email": "gregg@kellogg-assoc.com",
• Transform information
"url": "https://api.github.com/users/
gkellogg",
"avatar_url": "...",
"id": 46296,
• Add @id to data
{
}
+
"login": "gkellogg"
• Other programmatic
transformations
"https://api.github.com/users/*": {
"$": {
"@context": {
"foaf": "http://xmlns.com/foaf/0.1/",
"foaf:depiction": {"@type": "@id"},
"gh": "https://api.github.com/vocabulary#"
},
"@id": [{"f:valueof": "login"},
{"f:prefix": "http://github.com/"}],
"@ns": {
"ns:default": "gh",
"ns:replace": {"avatar_url": "foaf:depiction", "name":
"foaf:name"}
},
"@only": ["avatar_url", "name", "followers"],
"@type": ["gh:User", "foaf:Person"]
}
}
}
* json-ld-macros courtesy of Antonio Garrote

43. {
Macros
"type": "User",
"followers": 35,
"name": "Gregg Kellogg",
"email": "gregg@kellogg-assoc.com",
• Transform information
"url": "https://api.github.com/users/
gkellogg",
"avatar_url": "...",
"id": 46296,
• Add @id to data
{
}
+
"login": "gkellogg"
• Other programmatic
transformations
"https://api.github.com/users/*": {
"$": {
"@context": {
{
"foaf": "http://xmlns.com/foaf/0.1/",
"@context": {
"foaf:depiction": {"@type": "@id"},
"foaf": "http://xmlns.com/foaf/0.1/",
"gh": "https://api.github.com/vocabulary#"
"foaf:depiction": {"@type": "@id"},
},
"gh": "https://api.github.com/
"@id": [{"f:valueof": "login"},
vocabulary#"
{"f:prefix": "http://github.com/"}],
},
"@ns": {
"@id": "https://api.github.com/users/
"ns:default": "gh",
gkellogg",
"ns:replace": {"avatar_url": "foaf:depiction", "name":
"@type": ["gh:User", “foaf:Person”],
"foaf:name"}
"foaf:name": "Gregg Kellogg",
},
"foaf:depiction": "http://...",
"@only": ["avatar_url", "name", "followers"],
“gh:followers”: 35
"@type": ["gh:User", "foaf:Person"]
}
}
}
* json-ld-macros courtesy of Antonio Garrote

44. The “LD” in JSON-LD
• IRIs are first-class http://greggkellogg.net/foaf
citizens {
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
}
http://www.markus-lanthaler.com
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}

45. The “LD” in JSON-LD
• IRIs are first-class http://greggkellogg.net/foaf
citizens {
"@context": "http://json-ld.org/contexts/person",
• Object definitions may
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
be referenced or "name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
embedded }
http://www.markus-lanthaler.com
{
{ "@context": "http://json-ld.org/contexts/person",
"@context": "http://json-ld.org/contexts/person", "@id": "http://www.markus-lanthaler.com/",
"@id": "http://greggkellogg.net/foaf#me", "@type": "Person",
"@type": "Person", "name": "Markus Lanthaler",
"name": "Gregg Kellogg", "knows" "http://greggkellogg.net/foaf#me"
"knows": { }
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}

46. RDF 
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}

47. RDF 
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}

48. RDF 
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}
@prefix: schema <http://schema.org/> .
<http://greggkellogg.net/foaf#me> a schema:Person;
schema:name “Gregg Kellogg”;
shema:knows <http://www.markus-lanthaler.com/> .
<http://www.markus-lanthaler.com/> a schema:Person
schema:name “Markus Lanthaler”
schema:knows <http://greggkellogg.net/foaf#me> .

49. JSON-LD API
• compact – use minimal representation
using a supplied @context
• expand – expand to full form, removing
embedded @context definitions
• frame – query for JSON-LD
• fromRDF/toRDF

50. More Information
json-ld.org JavaScript
Ruby
w3c Python
PHP
Java
Gregg Kellogg C++
gregg@greggkellogg.net
http://greggkellogg.net/
http://www.slideshare.net/gkellogg1/json-for-linked-data
@gkellogg