A consent link is a pre-authenticated URL that creates a consent event when it gets accessed from a browser. Consent links can be used to show or send users links that they can click to update their consent status. This includes use cases like unsubscribing from all communications in an email, sending a confirmation email with an action button, etc.

We support two types of authorization for consent links:

• ​Pre-authorized: Consent links are pre-created by calling the Didomi API and include a unique signed token in the URL. This requires an API request to create the consent link. This is the recommended way to create consent links.

• ​Digest: Consent links are created on-the-fly and include a unique hash digest or HMAC signature to authenticate them. This does not require a request to the Didomi API and consent links can be generated entirely on your server. This is useful for environments where sending HTTP requests is complicated (emailing providers, for instance).

Consent links with pre-authorization

To create a consent link for a user, send a POST request to https://api.didomi.io/consents/links?organization_id=<ID of your organization> and specify the following parameters in the body:

Example:

POST https://api.didomi.io/consents/links?organization_id=<ID of your organization>
{
    "organization_user_id": "<User ID>",
    "action": "event.create",
    "event": {
        "consents": {
            "purposes": [
                ...Update to purposes
            ]
        }
    },
    "redirect_url": "https://www.ourwebsite.com"
}

The API will respond with the created link in the url field:

{
    "organization_user_id": "<User ID>",
    "action": "event.create",
    "event": {
        "consents": {
            "purposes": [
                ...Update to purposes
            ]
        }
    },
    "redirect_url": "https://www.ourwebsite.com",
    "url": "https://api.privacy-center.org/consents/execute/..."
}

The created link includes a unique token. When loaded in a browser, the corresponding event will be created or updated without any other authentication required.

The /consents/links endpoint of the API is used to create consent links. For a full reference of the endpoint and the resources that it returns, visit https://api.didomi.io/docs/.

Action and event

When executing a consent link, the Didomi API will execute the action that is defined in the action parameter of the consent link. That action can be either creating a new consent event (event.create) or updating an existing consent event (event.update).

Creating an event

The event to create must be specified in the event parameter. The event schema is the standard Didomi consent event schema.

For instance, to unsubscribe a user from a purpose, you could send the following JSON event:

{
    "consents": {
        "purposes": [{
            "id": "purpose_id",
            "enabled": false
        }]
    }
}

Any event that can be created through the regular POST /consents/events API can be created with a consent link with the same structure.

Updating an event

The event to update must be specified in the event parameter. The event schema is the standard Didomi consent event schema. An id field must be specified with the ID of an existing consent event to update. The other properties specified in the event parameter will be merged into the event.

For instance, to confirm an event that was previously in status pending_approval, you could send the following object:

{
    "id": "ddd2a1cd-589d-4f44-98f5-0b828a1c2a36",
    "status": "confirmed"
}

Consent links with digest authorization

Digest authorization allows you to specify all the parameters of a consent link (organization user ID, event to create/update, etc.) in the query-string parameters of a URL. To authorize that request, you must add a digest computed from the organization user ID and a secret shared with Didomi. This ensures that the request originates from your servers and cannot be freely created.

When using digest authorization, you must build the consent link URL yourself from scratch. The base of the URL is https://api.privacy-center.org/v1/consents/execute to which you can add the query-string parameters that form your consent link. Example of a consent link with digest authorization: https://api.privacy-center.org/v1/consents/execute?key=fe295974-e126-49a4-9d6f-84bc5884c298&auth_algorithm=hash-md5&auth_sid=secret-id&auth_digest=e067d565e248267d5c3dd2f82409f5e3&auth_salt=salt&organization_user_id={organization_user_id}&action=event.create&event=%7B%22consents%22%3A%7B%22purposes%22%3A%5B%7B%22id%22%3A%22purpose_id%22%2C%22enabled%22%3Afalse%7D%5D%7D%7D&redirect_url=https%3A%2F%2Fwebsite.com​

This link is composed of the following parameters:

Read on for more information on every parameter and how they are built.

Digest

Digest and algorithm (auth_algorithm and auth_digest)

The digest is a hex-encoded string computed by running a hash or HMAC algorithm on the concatenated organization_user_id and secret. The digest must be provided in the auth_digest query-string parameter of the consent link.

For example and assuming your organization user ID is [email protected] and your secret value is secret_value, you could compute a MD5 hash digest as MD5([email protected]_value) = 2d7d57c0b588a5c4bc508b17ace5fd7e. Note that there is no separator between the organization user ID and the secret.

We support the following digest types and algorithms:

We recommend using Hash / SHA256 or HMAC / SHA256 if possible. The algorithm that you will be using must be provided in the auth_algorithm query-string parameter of the consent link.

Secret (auth_secret)

The digest is used as a proof that the consent link was created by your organization and not by a third-party generating a consent link for your users without authorization. For the digest to be a valid prood, it needs to include a unique secret value only known by Didomi and your organization. When the Didomi API receives a consent link with a digest, it re-computes the digest and compares it with the provided digest. If the digests match, the consent link was created by an organization that knows the secret value associated with the consent link.

For Didomi to be able to compute the digest, you must specify the ID of the secret value that was used for computing the digest on your side. To do so, specify the auth_sid query-string parameter with the ID (not the secret value!) of the secret used for the digest.

You can create and manage secrets by reading our documentation.

Salt (auth_salt) - Optional

To further improve the security of the secret, you can include a random unique salt in every consent link that you create. The digest should then be computed on the organization user ID, the secret, and the salt.

For example and assuming your organization user ID is [email protected] , your secret value is secret_value, and your salt is salt, you could compute a MD5 hash digest as MD5([email protected]) = e067d565e248267d5c3dd2f82409f5e3. Note that there is no separator between the organization user ID, the secret, and the salt.

The salt must be provided in plain-text in the auth_salt query-string parameter of the consent link. The salt is not secret and it is safe to pass it unencrypted. The salt is present to increase the uniqueness of the digest and make it harder for attackers to guess the secret with pre-computed hash attacks. We recommend generating a new random salt for every consent link that you create.

Action and event

When executing a consent link, the Didomi API will execute the action that is defined in the action query-string parameter of the consent link. That action can be either creating a new consent event (event.create) or updating an existing consent event (event.update).

Creating an event

The event to create must be specified as a URL-encoded JSON consent event in the event query-string parameter. The event schema is the standard Didomi consent event schema.

For instance, to unsubscribe a user from a purpose, you could send the following JSON event:

{
    "consents": {
        "purposes": [{
            "id": "purpose_id",
            "enabled": false
        }]
    }
}

URL-encoded to fit in a query-string, you would get:

%7B%22consents%22%3A%7B%22purposes%22%3A%5B%7B%22id%22%3A%22purpose_id%22%2C%22enabled%22%3Afalse%7D%5D%7D%7D

Any event that can be created through the regular POST /consents/events API can be created with a consent link with the same structure.

Updating an event

The event to update must be specified as a URL-encoded JSON consent event in the event query-string parameter. The event schema is the standard Didomi consent event schema. An id field must be specified with the ID of an existing consent event to update. The other properties specified in the event parameter will be merged into the event.

For instance, to confirm an event that was previously in status pending_approval, you can could send the following JSON:

{
    "id": "ddd2a1cd-589d-4f44-98f5-0b828a1c2a36",
    "status": "confirmed"
}

Redirection

You can provide a URL to redirect the user to after executing the action via the redirect_url query-string parameter for digest authorization, and via the redirect_url body parameter for pre-authorization.

If an error happens while executing the action, Didomi will append an error query-string parameter to the redirection URL. The error parameter will contain an error code and can be used to show an error message to the user to let them know that their action has failed.

Example

If the provided redirect URL is https://www.ourwebsite.com/consent-updated, then:

• Didomi will redirect to https://www.ourwebsite.com/consent-updated if the action is successful

• Didomi will redirect to https://www.ourwebsite.com/consent-updated?error=[ERROR CODE] if the action fails to execute

Error codes

The error query-string parameter will contain one of the following error codes: