Reference
Captured Fields Reference
SourceTag captures attribution data and populates it into hidden form fields. This page documents every field, organised by group.
How field names work
Every field is prefixed with st_ to avoid clashes with your existing form fields.
For attribution data that differs between first and last contact, there are two versions:
st_fc_fields contain first contact data (the visitor’s original touchpoint)st_lc_fields contain last contact data (the most recent touchpoint before conversion)
For example, st_fc_channel holds the channel from the visitor’s very first visit, while st_lc_channel holds the channel from their most recent visit that had new attribution data.
Fields that aren’t tied to a specific touchpoint (like visit count or device type) use just the st_ prefix.
When a field has no value (e.g. no utm_term was present), the form field is populated with (not set) rather than left blank. This makes it clear in your CRM that the field was captured but had no value.
Core fields (always included)
These 12 fields are always populated. They give you the essential attribution picture for every lead.
| Field name | Description |
|---|---|
st_fc_channel | First contact channel (e.g. Paid Search, Organic Social, Direct) |
st_fc_detail_1 | First contact detail 1 (content depends on the channel, see below) |
st_fc_detail_2 | First contact detail 2 |
st_fc_detail_3 | First contact detail 3 |
st_fc_detail_4 | First contact detail 4 |
st_lc_channel | Last contact channel |
st_lc_detail_1 | Last contact detail 1 |
st_lc_detail_2 | Last contact detail 2 |
st_lc_detail_3 | Last contact detail 3 |
st_lc_detail_4 | Last contact detail 4 |
st_fc_landing_page | First contact landing page (path + query string, e.g. /pricing?ref=nav) |
st_lc_landing_page | Last contact landing page |
What goes in the detail fields?
The detail fields contain different data depending on the channel. Each channel has its own mapping, configured in the channel editor. The defaults are:
| Channel | Detail 1 | Detail 2 | Detail 3 | Detail 4 |
|---|---|---|---|---|
| Paid Search | utm_source (e.g. google) | utm_campaign | utm_term | utm_content |
| Paid Social | utm_source (e.g. facebook) | utm_campaign | utm_term | utm_content |
| Display | utm_source | utm_campaign | utm_term | utm_content |
| Paid Video | utm_source | utm_campaign | utm_term | utm_content |
| utm_source (e.g. mailchimp) | utm_campaign | utm_term | utm_content | |
| Affiliates | utm_source | utm_campaign | utm_term | utm_content |
| Other Campaigns | utm_source | utm_campaign | utm_term | utm_content |
| Organic Social | Referrer domain (e.g. facebook.com) | utm_campaign | utm_term | utm_content |
| Organic Search | Referrer domain (e.g. google.com) | Referrer URL | utm_term | utm_content |
| Referral | Referrer domain | Referrer URL | - | - |
| Direct | - | - | - | - |
These defaults can be customised per channel in the channel editor.
Extended field group: Raw UTMs
Enable the raw_utms group to capture the original UTM parameter values as separate fields, independent of the channel detail mapping.
| Field name | Description |
|---|---|
st_fc_source | First contact utm_source value |
st_lc_source | Last contact utm_source value |
st_fc_medium | First contact utm_medium value |
st_lc_medium | Last contact utm_medium value |
st_fc_campaign | First contact utm_campaign value |
st_lc_campaign | Last contact utm_campaign value |
st_fc_term | First contact utm_term value |
st_lc_term | Last contact utm_term value |
st_fc_content | First contact utm_content value |
st_lc_content | Last contact utm_content value |
When to use this: If you want the raw UTM values alongside the channel categorisation. The detail fields are mapped contextually (Detail 1 might be utm_source for one channel and referrer domain for another), so having the raw values as well can be useful for reporting.
Extended field group: Landing page groups
Enable the landing_page_groups group to capture a simplified version of the landing page path. This takes the first path segment only, which is useful for grouping landing pages by section.
| Field name | Description |
|---|---|
st_fc_landing_page_group | First contact landing page group (e.g. /blog, /pricing, /) |
st_lc_landing_page_group | Last contact landing page group |
When to use this: If you want to report on which section of your site visitors land on rather than the exact URL. For example, all blog posts would group under /blog.
Extended field group: Click ID (combined)
Enable the click_id_combined group to capture click IDs in a single pair of fields. If multiple click IDs are present, only the first one found is stored.
| Field name | Description |
|---|---|
st_fc_click_id | First contact click ID value |
st_fc_click_id_type | First contact click ID type (e.g. gclid, fbclid, msclkid) |
st_lc_click_id | Last contact click ID value |
st_lc_click_id_type | Last contact click ID type |
When to use this: If you just need to know whether a click ID was present and what type it was, without breaking them out into individual fields.
Extended field group: Click ID (individual)
Enable the click_id_individual group to capture each click ID in its own dedicated field. SourceTag checks for five click ID parameters: gclid, fbclid, msclkid, gbraid, and wbraid.
| Field name | Description |
|---|---|
st_fc_gclid | First contact Google Ads click ID |
st_lc_gclid | Last contact Google Ads click ID |
st_fc_fbclid | First contact Meta (Facebook) click ID |
st_lc_fbclid | Last contact Meta (Facebook) click ID |
st_fc_msclkid | First contact Microsoft Ads click ID |
st_lc_msclkid | Last contact Microsoft Ads click ID |
st_fc_gbraid | First contact Google Ads app click ID |
st_lc_gbraid | Last contact Google Ads app click ID |
st_fc_wbraid | First contact Google Ads web-to-app click ID |
st_lc_wbraid | Last contact Google Ads web-to-app click ID |
When to use this: If you’re running ads across multiple platforms and want to send the raw click IDs back to each ad platform for offline conversion tracking. Most CRM integrations that support offline conversions need the individual click ID fields.
Extended field group: Visitor meta
Enable the visitor_meta group to capture contextual data about the visitor and their journey that isn’t tied to a specific touchpoint.
| Field name | Description |
|---|---|
st_visits | Total number of sessions the visitor has had |
st_days_to_convert | Days between first visit and form submission |
st_device | Device type at time of submission: Mobile, Tablet, or Desktop |
st_submit_page | Page path where the form was submitted |
st_referrer | Referrer domain for the current page view |
When to use this: If you want to understand how many visits it took before a lead converted, how long the consideration period was, or which device they used when they finally filled in the form.
Custom parameters
You can configure SourceTag to capture arbitrary URL parameters beyond the standard UTMs and click IDs. These are set up in the Fields page of the SourceTag dashboard.
Custom parameters are stored as st_custom_{name}. For example, if you configure brand as a custom parameter, the field name will be st_custom_brand.
See Custom Parameters for full setup instructions.
Toggling field groups
Field groups are toggled on or off in the SourceTag dashboard under your site’s Fields page.
- Basic Mode lets you toggle entire groups on or off with a switch
- Advanced Mode lets you customise individual field names, add custom parameters, and set a form selector
When you change which groups are enabled, click Generate Script to rebuild and redeploy the script with the updated configuration.
[IMAGE: Screenshot of the SourceTag Fields page showing the toggle switches for each extended field group]
Field names in your CRM
When you create custom fields in your CRM (HubSpot, Salesforce, etc.), the CRM field’s internal name needs to match the SourceTag field name. Most CRMs generate internal names from the label you provide, so naming a field “ST FC Channel” usually produces an internal name like st_fc_channel.
Check the setup guide for your specific CRM: