URL API

Prefilled links remove friction from the donation process. Instead of asking supporters to enter information they've already provided or make decisions about amounts and frequency, you can guide them toward the right donation for their situation.

Consider these scenarios where prefilled links make donating more effective:

• Email campaigns. Send different donation amounts to different supporter segments. Your monthly donors might see a $75 suggested amount, while first-time supporters see $25.
• Direct mail follow-up. Include personalized URLs in printed materials that prefill supporter information when they visit online.
• Corporate partnerships. Provide employee giving links that automatically designate donations to your partnership fund and include company identifiers for tracking.
• Membership drives. Create links with locked amounts for annual memberships, preventing supporters from changing the membership price.
• A/B testing. Test different suggested amounts or designations by sending different URL variations to similar audience segments.

A parameter is a short instruction that tells Fundraise Up what information to prefill. You can use multiple parameters in one link to customize the entire donation experience.

First, get your base donation link from your Dashboard. Go to Campaigns > [Your campaign name] and copy the link for your Checkout Modal or Campaign Page. Then add parameters to this link:

• Start the first parameter with a ?.
• Separate additional parameters with &.
• Replace spaces with %20 (standard URL formatting).

Here's a sample link that opens the Checkout Modal with these values prefilled:

• Name: Alex Garcia
• Email: alex.garcia@example.com
• Amount: $100
• Currency: USD
• Frequency: one-time

Breakdown of the URL parameters:

• form=FUNCPJTZZQR — The unique ID of the campaign the donation will go to.
• firstName=Alex — Supporter's first name.
• lastName=Garcia — Supporter's last name.
• email=alex.garcia@example.com — Supporter's email address.
• amount=100 — The donation amount shown in the form.
• currency=USD — Sets the currency (helpful for international supporters).
• recurring=once — Sets the frequency to one-time.

When supporters click this link, they see their name and donation details already filled in. All they have to do is confirm and complete the payment.

Each parameter adds specific information to your donation forms. Add them to your URLs using the format shown above. The order of parameters doesn't affect functionality.

Think carefully before including personally identifiable information (PII) in your URLs. PII includes names, addresses, phone numbers, and email addresses. While prefilling this information improves the supporter experience, it can create privacy and compliance issues.

For most campaigns, focus on donation-specific parameters like amount, recurring, and designationId rather than personal information. Use personalized links in direct emails, newsletters, or messages to known supporters, but remove personal details for public campaigns.

The URL API works with three different Fundraise Up donation experiences: Checkout Modal, Campaign Page and Donation Form element.

The Checkout Modal is an overlay that appears on top of your website content, allowing supporters to donate without leaving the current page.

Campaign Pages are dedicated donation landing pages hosted by Fundraise Up, featuring customizable content alongside the checkout form.

The Donation Form embeds your checkout form directly within your webpage layout, rather than opening as an overlay.

To use URL parameters with Donation Forms, the URL must include the form’s elementId. If the elementId is missing or doesn’t match any element on the page, other parameters will be ignored.

Personal information submitted through URLs won't appear on the Donation Form itself, but will display during checkout when accessed from the form.

You can prevent supporters from changing prefilled amount or designation by using the modify parameters. This works well for specific initiatives or membership programs where you want to control the donation experience.

Fixed amount example:

Fixed designation example:

If the prefilled donation amount is invalid — for example, it’s 0, missing, outside the allowed minimum or maximum, or uses fractional units not permitted for the account — the modifyAmount=no parameter is ignored. In those cases, the amount becomes editable so the supporter can complete the donation.

You can also use Fundraise Up’s custom fields with the URL API to pass additional values along with donation parameters. This is helpful for tracking traffic sources, partner IDs, membership numbers, or any other context-specific data.

Before using a custom field in your URL, you need to create it in your campaign’s settings in the Dashboard. The field name in the URL must exactly match the name of the custom field you create.

Once the field exists in the Dashboard, you can use it like any other URL parameter:

• Add them to your base donation link using the same ? and & syntax.
• Values can be up to 200 characters and should replace spaces with %20 for proper URL encoding.
• You define both the field name (created in the Dashboard) and the value you want to record.

For example, if you’ve created a custom field called traffic_channel for your campaign, you can include it in the URL like this:

You can combine custom fields with regular URL API parameters:

You can later view these custom field values:

• On individual donation records in the Donations tab of your Dashboard (scroll to Custom fields section).
• In exports, where they appear as additional columns.
• In integration mappings to CRMs or analytics tools.

Add fundraiseupLivemode=no to any URL to test your parameters without processing real donations. This lets you verify that information appears correctly before launching your campaign.

You can use links with parameters anywhere you normally share donation links:

• Email campaigns.
• SMS or messaging apps like WhatsApp.
• Social media posts.
• Buttons or images on your website.