For questions around the concepts and terminology specific to Solid, refer to


An Access Control List is a Resource that controls users’ level of access ({ read: <boolean>, append: <boolean>, write: <boolean>, control: <boolean> }) to a Resource. For example, it can list rules like “ can read this Resource”, and “ can read this Resource and its children”. See also Access Modes, or read about how you can read and change it at Manage Access to Data (WAC).

Access Control Policies#

One of the access control mechanisms that can be used with Solid. See Manage Access to Data (ACP).


A user. Agent typically refers to a person but could also refer to other users, e.g., bots.

Access Modes#

The types of access that have been granted: Read Access, Append Access, Write Access and/or Control Access.

Append Access#

Access to add data to the applicable Resource.


An application; also referred to as client application. Can be Web-based, server-based, CLI tools, etc.

For information on WebID-based authentication for client applications, see Authenticate Client Applications (Browser & Node.JS).

Control Access#

Access to view and manage who has access to the applicable Resource.

Applicable to the ACL authorization system.


A special type of Resource that can contain other Resources or Containers, much like folders on your file system. Technically, a Container is itself a SolidDataset.

For example, given a Resource at, both and are Containers.

The URL for a Container ends with a slash /.

Default access#

Rules defining Access Modes that apply not to the Container Resource directly, but are inherited by its children, their children if applicable, and so forth.

Fallback ACL#

If a Resource does not have an explicit Resource ACL of its own, the Fallback ACL is the ACL of the Container closest to that Resource that does have its own explicit Resource ACL. Only the Default access rules in the Fallback ACL apply.


Internationalized Resource Identifier. An IRI is similar to standard web URI but allows for internationalized characters such as the umlaut Ä, or the Greek letter Δ. See also IRI Wikipedia page.


Storage location for your data. You manage the access to data stored in your Pod.


The data sent to you when you type a URL into a web browser.

Resource ACL#

The ACL that applies to a given Resource. If none exists, the Fallback ACL applies.

Read Access#

Access to view the contents of the applicable Resource.


Set of Things. For more information, see Structured Data.


A data entity, e.g., a person. A Thing is associated with a set of data or properties about the Thing, e.g., name, date of birth, address, etc.

A Thing is saved as part of a SolidDataset, where a SolidDataset is a set of Things. For more information, see Structured Data.

Web Access Control#

One of the access control mechanisms that can be used with Solid, based on Access Control Lists. See Manage Access to Data (WAC).


A URL that identifies an Agent. The Resource found at the WebID can provide more information about this Agent or Client, such as the location of their data.

For more information on WebID URL, see

Write Access#

Access to add (i.e. append), update, and delete contents of Resource. Granting Write access automatically grants Append Access.