Fundraise Up does not support sending webhooks to an external URL of your choosing — this is a limitation of Fundraise Up itself, not something specific to LettrLabs, and their own documentation points customers toward Zapier instead. There is no "Native Webhook Setup" article for Fundraise Up the way there is for HubSpot, JobNimbus, or GoHighLevel — here are the two real options if a Zapier-free path is what you're after.

Rather than using the dedicated LettrLabs action inside Zapier (as in Setup Guide: Fundraise Up), build a Zap using Fundraise Up as the trigger and Webhooks by Zapier ("Custom Request") as the action, pointed at your LettrLabs inbound webhook URL (see Setup Guide: Open API & Webhooks). This still uses Zapier, but gives you full control over the JSON body and headers sent to LettrLabs, rather than being limited to the fields the native LettrLabs Zapier action exposes.

Fundraise Up's REST API can be polled for new donations, or your own backend can call it and forward matching records to LettrLabs' webhook URL. This is a developer-built path, and Fundraise Up's own documentation notes it requires technical knowledge to set up — worth the investment only if Option 1 doesn't cover a specific field or volume requirement you need.

For most Fundraise Up customers, Setup Guide: Fundraise Up (Zapier) — using the dedicated, pre-built LettrLabs action — is simpler and sufficient. Reserve Option 1 or 2 above for cases where you need a field or behavior the native Zapier action doesn't support.

Questions about which path fits your Fundraise Up setup? Reach out to our team.