How do I get the most out of opt-in forms?

Opt-in forms are your primary tool for growing your contact list with people who genuinely want to hear from you. With a bit of strategic thinking, they can do much more than just collect email addresses.

Connect your form to your database

Before you can use form responses for personalisation or segmentation, the form fields need to be connected to your Flexmail contact fields. This happens automatically for default fields (email, first name, last name, language) and for any custom fields you add to your form.

One important limitation: forms cannot create new fields in your database. If you want to collect a piece of data that doesn't yet have a corresponding field, create the field in Settings > Manage custom fields first, then add it to your form.

Use personalisation in your form

If you share your opt-in form via an email campaign, for example, to ask existing contacts to update their preferences, you can personalise the form using placeholders. Contacts who open the link from your email will see their name in the form greeting and have their known fields pre-filled.

This makes the experience feel personal and reduces the amount of data contacts need to re-enter. To use personalisation, always share the form as a link in an email rather than as a public embed, public embed forms can't pre-fill data because there's no contact context.

Use your form for preference updates

Your opt-in form isn't just for new subscribers. You can link to it in campaigns to invite existing contacts to update their preferences, add interests, or complete fields they left blank when they first signed up.

This is especially useful when you're launching a new interest category and want to give your existing audience the opportunity to subscribe to it. Send a campaign with a link to the form, explain what's new, and let them opt in.

Build segments from form subscriptions

Every opt-in form has a source name that's automatically recorded on contacts who subscribe through it. You can build segments based on which form a contact used to subscribe, useful for separating contacts from different pages or campaigns on your website.

For example: contacts who subscribed through your homepage form may have different interests than contacts who subscribed through a product-specific landing page. Segmenting on the source lets you treat them differently from the start.

Connect forms to workflows

A workflow triggered by an opt-in form subscription is one of the most impactful automations you can build. The moment a contact confirms their subscription, the workflow starts, sending a welcome email, a follow-up series, or assigning interests based on which form they used.

In your workflow's start block, select 'Contacts who subscribed via' and choose your form. This ensures only contacts from that specific form enter that specific workflow.

Track form performance

Your opt-in forms overview shows how many contacts have subscribed through each form. Use this data to compare form performance over time and across different placements on your website. A form that's getting very few submissions despite being on a high-traffic page is worth investigating, the problem might be placement, copy, or the offer.