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 click, there are two versions:
**st_fc_**fields contain first click data (the visitor’s original touchpoint)**st_lc_fields containlast click** 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 click channel (e.g. Paid Search, Organic Social, Direct) |
st_fc_detail_1 | First click detail 1 (content depends on the channel, see below) |
st_fc_detail_2 | First click detail 2 |
st_fc_detail_3 | First click detail 3 |
st_fc_detail_4 | First click detail 4 |
st_lc_channel | Last click channel |
st_lc_detail_1 | Last click detail 1 |
st_lc_detail_2 | Last click detail 2 |
st_lc_detail_3 | Last click detail 3 |
st_lc_detail_4 | Last click detail 4 |
st_fc_landing_page | First click landing page (path + query string, e.g. /pricing?ref=nav) |
st_lc_landing_page | Last click landing page |
Note: UTM parameters and click IDs (gclid, fbclid, msclkid, etc.) are stripped from the landing page URL. Only the path and any other query parameters are preserved.
What goes in the smart fields?
The smart fields contain different data depending on the channel. Each channel has its own mapping, configured in the channel editor. The defaults are:
| Channel | Smart Field 1 | Smart Field 2 | Smart Field 3 | Smart Field 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 click utm_source value |
st_lc_source | Last click utm_source value |
st_fc_medium | First click utm_medium value |
st_lc_medium | Last click utm_medium value |
st_fc_campaign | First click utm_campaign value |
st_lc_campaign | Last click utm_campaign value |
st_fc_term | First click utm_term value |
st_lc_term | Last click utm_term value |
st_fc_content | First click utm_content value |
st_lc_content | Last click utm_content value |
When to use this: If you want the raw UTM values alongside the channel categorisation. The smart fields are mapped contextually (Smart Field 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: 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 click click ID value |
st_fc_click_id_type | First click click ID type (e.g. gclid, fbclid, msclkid, ttclid) |
st_lc_click_id | Last click click ID value |
st_lc_click_id_type | Last click 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 six click ID parameters: gclid, fbclid, msclkid, ttclid, gbraid, and wbraid.
| Field name | Description |
|---|---|
st_fc_gclid | First click Google Ads click ID |
st_lc_gclid | Last click Google Ads click ID |
st_fc_fbclid | First click Meta Ads click ID |
st_lc_fbclid | Last click Meta Ads click ID |
st_fc_msclkid | First click Microsoft Ads click ID |
st_lc_msclkid | Last click Microsoft Ads click ID |
st_fc_gbraid | First click Google Ads app click ID |
st_lc_gbraid | Last click Google Ads app click ID |
st_fc_wbraid | First click Google Ads web-to-app click ID |
st_lc_wbraid | Last click Google Ads web-to-app click ID |
st_fc_ttclid | First click TikTok click ID |
st_lc_ttclid | Last click TikTok 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 |
st_fc_date | Date of the visitor’s first click (first visit) |
st_lc_date | Date of the visitor’s last click (most recent attribution visit) |
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 follow the same first click / last click model as the rest of your attribution data. They’re stored as st_fc_custom_{name} and st_lc_custom_{name}. For example, if you configure brand as a custom parameter, the field names will be st_fc_custom_brand and st_lc_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. Each extended group has a toggle switch. Turn on the groups you need, add any custom parameters, then save.
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 CRM to make sure the internal field names match.
Doesn't answer your question or need more help? Get in touch.