What a custom field is
FoxReach has a fixed set of boxes for a lead: email, first name, last name, company, job title, phone, LinkedIn URL and website. Everything else in your spreadsheet is a custom field. The column header becomes the field’s name and the cell becomes its value, one per lead. So a sheet with aSignal column gives every lead a custom field called Signal. Alex has “Hiring SDR Manager” in it, Priya has “Raised Series A”, and a lead with an empty cell has nothing there.
How custom fields get in
From a CSV import
Upload the file on the Leads page as usual. The upload step already says so in its format tips: custom columns are kept.
The upload step of Import Leads, with the CSV format tips: the last one says custom columns are preserved as custom fields

Close-up of the CSV format tips card on the upload step

The Map Fields step after uploading a CSV with a Signal column: the standard lead fields each get a column, and Signal, which matches none of them, is kept as a custom field
By hand, on a lead
Open any lead and look for the Custom Fields card. It lists what came in with the import, with a count in the corner.
A lead page with the Custom Fields card showing two fields, techStack and signal, that arrived with the import

Close-up of the Custom Fields card on a lead page
signal to a lead who came in without one. The new field is usable in emails straight away.

The Custom Fields card in edit mode, with the existing fields editable and the Add field button below them
From another tool
If leads reach FoxReach from a CRM, a form or a script, custom fields travel with them. The API keys and webhooks page shows where to start; the fields work the same way once they are on the lead.Where custom fields show up
- On the lead page, in the Custom Fields card.
- In the Variables menu when you write an email, under their own heading, with a real lead’s value next to each one so you can see what it looks like filled in.
- In exports. Download your leads as a CSV and every custom field is a column again.
Using them in an email
Open a sequence step, a template or a one-off email and click Variables above the subject line or the body. The menu lists FoxReach’s standard fields first, then a Custom Fields section with every field your leads have. Click one to insert it where your cursor is.
The step editor with the Variables menu open and scrolled to its Custom Fields section, listing signal and techStack with a sample value for each

Close-up of the Custom Fields section of the Variables menu
{{signal}}. The name has to match the header exactly, capital letters included, so if the column was Signal, write {{Signal}}.
When FoxReach sends the email, each variable is replaced with that lead’s value. This works in the subject line as well as the body, and in templates you save for later.
Say what to write when a lead has no value
Not every lead will have every field. Before you insert a variable, type a fallback into the box at the top of the Variables menu, the one labelled If the lead has no value, use. FoxReach inserts the variable with that fallback built in, like{{signal|growing the team}}. Leave the box empty and the variable simply disappears for leads without a value, so a sentence like saw you are {{signal}} would end mid-air. Give it a fallback.

The Variables menu with a fallback typed into the If the lead has no value box, so the inserted variable carries it

Close-up of the fallback box at the top of the Variables menu
Check it before you send
Under every step editor there is a Preview with and without lead data section. Open it and you see the email twice: once for a lead who has every field, and once for a lead who has none. The second one is the honest test. If it reads “Hi ,” or “Quick question about ,”, a variable is missing its fallback.
The preview under a step editor open to both versions: Lead with data on the left and Lead missing data on the right, where the company variable without a fallback leaves a gap

Close-up of the two previews side by side
Three ways people use them
A reason column. Add asignal column with the thing that put each person on the list: “hiring an SDR manager”, “just raised a Series A”, “opened a second office”. Then open with it: Saw you are {{signal|building out sales}}, so this might be timely.
A tool column. If you replace or plug into other software, a techStack column lets you name it: Teams on {{techStack|a CRM}} usually bolt three tools onto it for outreach.
A line written by hand. For a short, high-value list, add an opener column and write one sentence per person. The email body is then just {{opener}} followed by your pitch. This is the most personal cold email you can send at scale, and FoxReach does not care that the column is a whole sentence.
Good to know
- Blank cells are fine. The lead gets no value for that field and the fallback shows instead.
- Importing again does not update existing leads. A lead whose email is already in the workspace is skipped by the import, so changed cells in a re-upload are not applied. Edit the lead on its page instead.
- Names are case-sensitive.
{{signal}}and{{Signal}}are two different fields. - Limits. Up to 50 custom fields per lead, names up to 100 characters, values up to 5,000 characters. A value is text; a number or a date is kept as the text you typed.
- Custom fields are per workspace. Leads in another workspace have their own.
Related guides
- Import leads from a CSV
- Create a campaign and write the sequence
- Email templates
- API keys and webhooks
Frequently asked questions
Do I have to set custom fields up before importing?
Do I have to set custom fields up before importing?
Why is my variable coming out blank?
Why is my variable coming out blank?
Can I use a custom field in the subject line?
Can I use a custom field in the subject line?
What happens to custom fields when I export?
What happens to custom fields when I export?
How do I change a custom field on many leads at once?
How do I change a custom field on many leads at once?