UDFs

A UDF record holds the Python source (udf_body), a slug, and its placement on a canvas. These endpoints manage the records; to execute a UDF see Running UDFs.

The UDF object

Field	Type	Description
id	string	UDF id
slug	string	URL-safe name, unique within a canvas
udf_body	string	The UDF source and metadata
collection_id	string | null	Canvas the UDF belongs to
collection_name	string | null	Canvas name
is_visible	boolean	Whether the UDF is shown on its canvas
position	integer	Ordering on the canvas
udf_body_hash	string	Hash of udf_body, for change detection
last_updated	string	Last modification timestamp
owning_user	object | null	Owner summary

List your UDFs

GET /udf/self

Scope: user

Query parameters

Parameter	Type	Description
skip	integer	Offset. Default 0.
limit	integer	Page size. Default 300.

List your team's UDFs

GET /udf/exec-env/self

Scope: environment

Every UDF in your execution environment. Accepts the same query parameters. This is the listing to use with a service account token.

Get a UDF

GET /udf/by-id/{udf_id}

Scope: public or authorized — public UDFs are readable with no credentials; private ones require access.

Returns the UDF object.

By name

Several addressing schemes resolve a UDF without knowing its id:

Endpoint	Scope	Resolves
GET /udf/exec-env/self/by-collection/{canvas_name}/by-slug/{slug}	environment	A UDF on one of your team's canvases
GET /udf/by-user-handle/{handle}/by-collection/{canvas_name}/by-slug/{slug}	user or environment	A UDF owned by a user, addressed by handle
GET /udf/by-user-email/{email}/by-collection/{canvas_name}/by-slug/{slug}	user or environment	The same, addressed by email

Each has a variant without /by-collection/{canvas_name} that resolves the slug on the owner's default canvas.

By shared token

GET /udf/shared/by-token/{token}

Scope: by token.

Returns the UDF a shared token points at. This is how fused.load("fsh_…") resolves a token to code.

Create a UDF

POST /udf/new

Scope: user

Body

Field	Type	Required	Description
slug	string	Yes	URL-safe name
udf_body	string	Yes	The UDF source and metadata
udf_type	string	Yes	Use auto
collection_id	string	No	Canvas to add the UDF to
create_shared_token	boolean	No	Also mint a shared token. Default false.
shared_token_access_scope	string	No	public or team. Default team.

Returns the created UDF object; when create_shared_token is true it also includes shared_token.

Update a UDF

POST /udf/by-id/{udf_id}

Scope: user

Send only the fields you want to change: slug, udf_body, or collection_id. Returns the updated UDF object.

Delete a UDF

DELETE /udf/by-id/{udf_id}

Scope: user

warning

Deleting a UDF breaks any shared token or URL pointing at it. Cached results are not served after deletion.

See also

• Running UDFs — executing what you create here
• Canvases — the canvas a UDF belongs to
• Write UDFs securely — access control and sharing