Skip to content
NewSee how

A/B test subject lines & bodies (Template mode)

Create multiple email variants in a Template-mode campaign and compare their performance in analytics.

Tutorials
Campaigns
min read
7 min
steps
7 · Intermediate

  1. Understand A/B testing in Template mode

    A Template-mode campaign can hold multiple email variants for the same sequence position, so you can compare different copy against each other.

  2. Open your campaign's Email Template

    Open the Email Template config for a Template-mode campaign.

  3. Start a new variant

    Click A/B Testing (top-right of the templates list) or Add A/B variant below it to open the New A/B Variant form.

  4. Fill in the variant

    Enter a Template Name, Subject Line, and Email Body. Insert merge tags where they help personalize the copy.

    Fill in the variant

  5. Preview and save

    Optionally click Send Test to preview the variant in your own inbox, then click Create Template to save it.

  6. Add more variants

    Repeat to add additional variants. Each one gets a numbered #N badge marking its position in the sequence; the gap between variants is controlled separately by Wait/Delay nodes on the canvas.

  7. Compare results in analytics

    Launch the campaign and let it run, then compare your variants' performance in campaign analytics. Winner selection is manual (there's no automatic winner) so review the metrics yourself and edit or delete the underperforming variant.

Pro tips

  • Change one thing at a time

    Vary the subject or the opener (not both) so analytics can tell you what actually moved the needle.

  • Winner selection is manual

    Check reply and open rates in campaign analytics yourself, then delete or rewrite the weaker variant: there's no automatic winner.

  • Name variants descriptively

    Give each one a name like “short-subject” or “case-study-open” so analytics rows stay readable later.

  • Send Test on every variant

    A broken merge tag looks worse when it's your best test variant: preview each one before launch.

Frequently asked questions

How do I add an A/B variant?

Click A/B Testing or Add A/B variant, fill in the form, then click Create Template.

Does FirstSales pick the winner automatically?

No: comparison is manual. You review each variant's performance in campaign analytics and choose.

How do I know which variant won?

Compare their metrics side by side in campaign analytics.

What can I vary?

Template Name, Subject Line, and Email Body, including merge tags.

What does the #N badge mean?

It marks the variant's position in the sequence.

How do I set the delay between variants?

With Wait/Delay nodes on the canvas: not from within the variant form.

Can I test a variant before launch?

Yes: Send Test opens the test-email drawer so you can preview it in your own inbox first.

Campaigns

Outreach that keeps going after you log off.Leads, emails, follow-ups and replies, handled.

Connect unlimited mailboxes and let AI agents find leads, write each email and follow up. Or send your own templates in manual mode. From $29/mo.

Start your $1 trial See pricing

$1 for 3 days · Cancel anytime · No contract

Install with AI

Your coding agent sets up the FirstSales CLI and skills for you.

Prompt for Claude Code

I'm setting up FirstSales (https://firstsales.io), an AI outbound sales platform: campaigns, contacts, a reply inbox, deliverability and lead signals. Help me get my workspace sending real, good emails end to end, from Claude Code.

Read these first so you know how FirstSales works:
- Developer docs and API: https://developer.firstsales.io
- CLI: https://www.npmjs.com/package/@firstsales.io/cli
- Skills for coding agents: https://github.com/firstsalesio/firstsales-skills (read README.md and GUIDE.md)

Setup
1. Install the CLI: npm install -g @firstsales.io/cli
2. Install the FirstSales skills:
   claude plugin marketplace add firstsalesio/firstsales-skills
   claude plugin install firstsales@firstsales
3. Ask me if I already have a FirstSales account. If not, send me to https://app.firstsales.io to sign up.
4. Ask me to create an API key under Settings → API → API Keys, with only the scopes we need.
   Never ask me to paste the key into this chat. Tell me to run this in my own terminal, so the key stays hidden:
   read -rs FS_KEY && firstsales auth login --api-key "$FS_KEY"; unset FS_KEY
5. Run `firstsales whoami` and tell me which workspace and organisation we are connected to.

Then ask me about my business: what I sell, who I sell to (roles, company size, countries), my best customers, and what I use today for outbound (tools, lists, mailboxes). Walk me through:
1. Teaching FirstSales my business: website, offer, proof points and case studies in the knowledge base, so the AI writes like someone who knows the product.
2. Connecting my sending mailboxes and checking my sending domain: SPF, DKIM, DMARC and warm-up. If anything is unhealthy, tell me the exact DNS record to add.
3. Bringing in contacts: import my CSV or CRM export into a clean list, remove duplicates and bad emails, and block domains I must never email (customers, competitors, my own).
4. Building my first campaign: the right list, senders, steps and timing. Write the sequence with me, show me the drafts, and do not launch until I say yes.
5. Setting up Signals if it fits: find people engaging with LinkedIn posts about topics my buyers care about, and turn them into leads.
6. Inviting my team and giving each person the right access.

Once campaigns run, show me how to work the reply inbox from here: which replies need an answer, draft responses in my voice, and move good conversations into deals. If I use Cal.com, connect it so follow-ups can offer my booking link (not the first email).

Throughout, as you learn about my business, proactively suggest and help create:
- Reply templates for the questions and objections my prospects are likely to raise, based on my product, site and codebase if you can see them.
- Campaign ideas and segments worth testing, with the reason for each.

Safety rules:
- Show every change as a dry run (--dry-run) first and wait for my yes. Never send emails, launch campaigns or delete anything without my yes.
- Tell me before anything that spends credits, and how many.

Be opinionated. If the docs give a sensible default, just use it. Don't make me choose between five options.
Developer docs ↗npm: @firstsales.io/cli ↗GitHub: firstsales-skills ↗