GET /dialog/contribute/pay_later

Returns an HTML-based dialog that allows users to make a single contribution that they can pay at a later date, using LaterPay’s micropayments via digital invoices.

Example URLs:

Available via HTTPS.

Required Parameters

campaign_id (required)

A unique identifier for tracking your donation goals (e.g., “2018-christmas-giving”, or “general-fund”). This will be used to show you analytics on how well each of your campaigns is doing. It can be any string consisting of lowercase or uppercase ASCII characters, digits, underscores, and hyphens, the length of which is betwen 1 and 128 characters.

pricing (required)

A string containing currency code and price matching your region. For example: "USD220" translates to $2.20 USD

title (required)

A user-friendly title that explains what the user is contributing to. This will be displayed in the LaterPay dialogs and in the user’s invoice.

url (required)

The URL where the user is sent after they successfully contribute. This might be your homepage, an article on your blog, or a specific landing page set up for your contribution campaign. Users will see this URL in their invoices. You can also specify a return_url (see below).

cp, hmac, ts (required)

Common Parameters

If the optional parameter permalink is present and equals 1 (see below), do not include ts.

Optional Paramters


If this parameter is present and its value is a 1, the generated link will not expire. Normally links expire after a certain amount of time, in order to minimize reuse.

The permalink and ts parameters are mutually exclusive. If permalink is 1, do not include the ts parameter (see above).


If you would like the user to be redirected to a different URL than what appears on their invoice, you can optionally provide return_url.


If this parameter is present and its value is a 1, the user will be asked to log in before they can commit to pay later for the contribution. Otherwise, users can accept the contribution without having to initially sign up for a LaterPay account.