When a link needs to arrive pre-filled — a campaign source, a customer ID, a referring user's email — you shouldn't have to build a custom field just to catch it. URL Parameters let a form capture values straight from the link that opened it.
1. Declare a parameter
In Form Settings, open the URL Parameters panel and add a parameter:
- Give it a name — this is the query string key MergePoint will look for (e.g.
utm_source,customer_id). - Optionally set a default value, used when the parameter isn't present in the URL.
- Optionally set a default binding instead of a static default — for example, binding
user_emailto the logged-in user's email, so the form still personalizes itself even without a query string.
2. Capture happens automatically
The moment the form loads, MergePoint reads the declared parameters straight from the URL's query string and stores them in session context for the rest of the form session — no field, no respondent input required.
3. Use the value in your form
Insert a recall token anywhere in field text — a label, instructions, or a message — using:
{{param:utm_source|Friend}}
The text after the | is the fallback shown if that parameter wasn't present in the URL.
4. Forwarding
Captured parameters are automatically carried forward if the form is shared onward (for example, a link generated mid-flow), so attribution and context aren't lost as a respondent moves between steps or forms.
Best practices
- Always set a fallback in your recall tokens — you can't guarantee every link that reaches the form includes the parameter.
- Use default bindings for internal context (like the logged-in user) and static defaults for external/marketing parameters (like campaign source).
- Keep parameter names consistent with the query string keys used in your marketing links or upstream systems — they're matched exactly.