> ## Documentation Index > Fetch the complete documentation index at: https://doc.lucidworks.com/llms.txt > Use this file to discover all available pages before exploring further. # Links API export const LwTemplate = ({title = "Key questions to get you started", icon = "sparkles", cta = "Powered by Agent Studio", linkHref = "https://lucidworks.com/demo/?utm_source=docs&utm_medium=referral&utm_campaign=docs_cta_ai"}) => { const [isLoaded, setIsLoaded] = useState(false); useEffect(() => { const timer = setTimeout(() => { setIsLoaded(true); }, 500); return () => clearTimeout(timer); }, []); return
{isLoaded && ` }} />} Powered by Lucidworks Agent Studio
; }; [localhost link]: http://localhost:3000/docs/4/fusion-server/reference/api/links-api [mintlify link]: https://doc.lucidworks.com/docs/4/fusion-server/reference/api/links-api [old doc.lw link]: https://doc.lucidworks.com/fusion/5.9/319 The Links API manages the links that represent the relationships between Fusion objects. You can see these links in the [Object Explorer](/docs/4/fusion-server/concepts/object-explorer) by pressing CMD-K or CTRL-K from any screen in the Fusion UI. You can also export and import links using the [Objects API](/docs/4/fusion-server/reference/api/objects-api). Links are structured as a tuple of `(subject, object, linkType)`. An example would be `(foo, bar, dependsOn)`, which would read as "foo dependsOn bar". ## Link types and link reversibility The possible values of `linkType` are as follows: | Link type | Example JSON | | ------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `inContextOf` | The subject exists in the context of the object, which is an app. In this example, the "Movie\_Search" app is the context for a parser with the same name: `{"subject": "parser:Movie_Search","object": "app:Movie_Search","linkType": "inContextOf","originator": "unspecified"}` | | `hasContext` | The subject is an app that contains the object. In this example, an index profile exists in the context of the "Movie\_Search" app: `{"subject": "app:Movie_Search","object": "index-profile:Movie_Search","linkType": "hasContext","originator": "unspecified"}` | | `dependsOn` | The subject depends on the object. In this example, a datasource called "web\_pokeapi\_co-default" depends on a parser by the same name: `{"subject": "datasource:web_pokeapi_co-default","object": "parser:web_pokeapi_co-default","linkType": "dependsOn"}` | | `supports` | The subject is depended on by the object (the reverse of `dependsOn`). In this example, a parser called "web\_pokeapi\_co-default" supports a datasource by the same name: `{"subject": "parser:web_pokeapi_co-default","object": "datasource:web_pokeapi_co-default","linkType": "supports"}` | | `isPartOf` | The subject is part of the object, where the object is a group. In this example, an aggregation called "click-signals-default" is part of a group called "signals-object-group-default": `{"subject": "aggregation:click-signals-default","object": "group:signals-object-group-default","linkType": "isPartOf"}` | | `hasPart` | The subject is a group, of which the object is a member (the reverse of `isPartOf`). In this example, a group called "signals-object-group-default" has an aggregation "click-signals-default": `{"subject": "group:signals-object-group-default","object": "aggregation:click-signals-default","linkType": "hasPart"}` | | `relatesTo` | The subject relates to the object. This is a uni‑directional relationship that associates two objects that have none of the relationships described above. For example, when recommendations are enabled for the default collection, Fusion creates a group which relates to the default collection: `{"subject": "group:recommendations-default","object": "collection:default","linkType": "relatesTo"}` | With the exception of the `relatesTo` link type, links are reversible: * `inContextOf` is the reverse of `hasContext` (and vice versa). * `dependsOn` is the reverse of `supports` (and vice versa). * `isPartOf` is the reverse of `hasPart` (and vice versa). For example, here is the group of links for the `signals-default` collection: ```json wrap theme={"dark"} [ { "subject": "group:4e6ee9a6-d4ab-413a-ac70-a27c1445bb60", "object": "collection:default_signals_aggr", "linkType": "hasPart" }, { "subject": "group:4e6ee9a6-d4ab-413a-ac70-a27c1445bb60", "object": "spark:default_click_signals_aggregation", "linkType": "hasPart" }, { "subject": "group:4e6ee9a6-d4ab-413a-ac70-a27c1445bb60", "object": "collection:default", "linkType": "relatesTo" }, { "subject": "group:4e6ee9a6-d4ab-413a-ac70-a27c1445bb60", "object": "collection:default_signals", "linkType": "hasPart" } ] ``` When we request the links for one of the `hasPart` objects shown above, we get the reverse representation: ```sh wrap theme={"dark"} GET https://FUSION_HOST:8764/api/links?subject=collection:default_signals_aggr [ { "subject": "collection:default_signals_aggr", "object": "group:4e6ee9a6-d4ab-413a-ac70-a27c1445bb60", "linkType": "isPartOf" } ] ``` ## Examples **Get links to the default collection:** ```bash wrap theme={"dark"} curl https://FUSION_HOST:8764/api/links?subject=collection:default ``` **Output:** ```json wrap theme={"dark"} [ { "subject": "collection:default", "object": "index-pipeline:default", "linkType": "supports" } ] ``` **Create a new link:** ```bash wrap theme={"dark"} curl -X PUT https://FUSION_HOST:8764/api/links -H 'content-type: application/json' -d '{"linkType": "supports", "object": "index-pipeline:default", "subject": "collection:default"}' ``` **Output:** ```json wrap theme={"dark"} { "subject" : "collection:default", "object" : "index-pipeline:default", "linkType" : "supports" } ``` **Delete a link:** ```bash wrap theme={"dark"} curl -X DELETE https://FUSION_HOST:8764/api/links?subject=collection:default ```