URL API
Add parameters to donation links to automatically fill checkout information.
Use Fundraise Up's URL API to create donation links that automatically fill in supporter and donation details when opened. This can make giving faster, increase conversions, and help you personalize the experience — especially in email campaigns, SMS outreach, and digital ads.
Why use prefilled donation links
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.
This lets you automatically personalize donation links for your entire email list rather than creating individual URLs manually for each supporter.
How to add parameters to the link
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
Click this link to see a demo campaign and how the parameters work.
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.
Available parameters
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.
| Parameter | Description | Example |
|---|---|---|
amount | Donation amount. Fundraise Up doesn't accept donations with cents (or other fractional currency units) by default. Contact us to enable fractional amounts. | amount=150 |
currency | Currency for the donation using ISO 4217 codes (USD for US dollars, EUR for euros). Combine with modifyAmount=no to prevent supporters from changing the currency. | currency=USD |
designationId | Sets a donation designation using the designation's ID from your Dashboard. | designationId=EHHJ9R36 |
elementId | Specifies which Donation Form to fill. Find your Donation Form ID in the Dashboard under Elements. | elementId=XRHREBFG |
email | Supporter's email address. | email=alex.garcia@example.com |
firstName | Supporter's first name. Content longer than 100 characters gets truncated. | firstName=Alex |
lastName | Supporter's last name. Content longer than 100 characters gets truncated. | lastName=Garcia |
modifyAmount | Prevents supporters from changing the prefilled amount. Set to no to lock the amount. Not available for Donation Forms. | modifyAmount=no |
modifyDesignation | Prevents supporters from changing the prefilled designation. Set to no to lock the designation. | modifyDesignation=no |
recurring | Sets donation frequency. Available options: once, daily, weekly, biweekly, every4weeks, monthly, bimonthly, quarterly, semiannual, annual. | recurring=monthly |
successUrl | Sets redirect URL instead of Fundraise Up’s default Thank you screen when Checkout Modal or Campaign Page is set to "Redirect to URL". Not available for Donation Forms. See example of the custom Thank you screen. | successUrl=https://example.com/thank-you |
tributeHonoree | Sets the tribute honoree name. Content longer than 200 characters gets truncated. Use %20 for spaces in URLs. | tributeHonoree=Mom%20and%20Dad |
_lang | Language for the checkout experience using ISO language codes for languages enabled in your account. Available options: ar, da, de, en-CA, en-GB, en-US, es, es-US, fi, fr-CA, fr-FR, hu, it, ja, ko, nl, no, pl, pt-BR, pt-PT, ru, sv, zh-CN, zh-TW. | _lang=en-US |
Privacy considerations
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.
firstName, lastName, and email. Learn more about Google's PII policies.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.
Implementation methods
The URL API works with three different Fundraise Up donation experiences: Checkout Modal, Campaign Page and Donation Form element.
Checkout Modal
The Checkout Modal is an overlay that appears on top of your website content, allowing supporters to donate without leaving the current page.
Click this link to see a demo campaign and how the parameters work.
Campaign Page
Campaign Pages are dedicated donation landing pages hosted by Fundraise Up, featuring customizable content alongside the checkout form.
Click this link to see a demo campaign and how the parameters work.
Donation Form
The Donation Form embeds your checkout form directly within your webpage layout, rather than opening as an overlay. Personal information submitted through URLs won't appear on the Donation Form itself, but will display during checkout when accessed from the form.
Click this link to see a demo campaign and how the parameters work. Scroll the page to the "Help stop the refugee crisis" section to see the Donation Form.
Locking donation details
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:
This link sets a $20 one-time donation that supporters cannot change. Click the link to see a demo campaign and how the parameters work.
Fixed designation example:
This link preselects a specific fund and prevents supporters from choosing a different designation. Find designation IDs in your Dashboard under Settings > Designations.
Test your setup
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.