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Monitor sender health & bounce rates

Read the per-mailbox health cards in campaign analytics (warmup score and bounce rate) and know when a sender is at risk.

Tutorials
Deliverability
min read
6 min
steps
7 · Intermediate

  1. What sender health tells you

    The Sender Health row shows per-mailbox warmup score and bounce rate for a campaign, so you can spot the one inbox dragging down the whole send before it costs you the domain.

  2. Open a campaign's Analytics

    Open a campaign and go to Analytics. Scroll to the Sender Health row. It only appears when the campaign is sending from 2 or more mailboxes: single-sender campaigns don't show it.

    Open a campaign's Analytics

  3. Read a healthy card

    Each mini-card shows the sender's email, a warmup gauge, Bounce %, and Sent count. A neutral border means nothing has tripped the health checks.

  4. Spot an at-risk card

    A card gets a red outline and a red Health issues info icon when either threshold trips: bounce rate above 5%, or warmup score below 50/100.

  5. Open the health-issues popover

    Click the red info icon to see the exact issue text: for example “High bounce rate (7.2% > 5%)” or “Low warmup score (41/100 < 50)”.

  6. Drill into a sender's emails

    Click a card to open that mailbox's sent-email list for the analytics date range you have loaded, so you can see exactly what went out.

  7. Act on it

    High bounce → clean the contact list and check Delivery Protection. Low warmup → give the mailbox more time to ramp, or pause it in this campaign until it's healthier. See the warm-up and bounce-recovery tutorials for the fixes.

Pro tips

  • Add a second sender to see it

    The row is hidden for single-mailbox campaigns by design. If you never see it, you're running one inbox: add a second sender and it appears.

  • A red card is a warning, not a failure

    Warmup below 50 usually means "still ramping," not "broken." Give a new mailbox time before scaling its volume onto this campaign.

  • 5% bounce is the same line Delivery Protection uses

    That threshold matches the platform's own auto-pause line: treat a red bounce card as "clean the list now," not "wait and see."

  • Check whether bounces cluster

    Click into the sender's email list to see whether bounces come from one bad import batch or spread across the whole list: that changes the fix.

Frequently asked questions

Why don't I see a Sender Health row?

It only renders for campaigns with 2 or more mailboxes. Single-sender campaigns hide it.

What makes a card turn red?

Either the mailbox's bounce rate is above 5%, or its warmup score is below 50 out of 100.

Can I change the health thresholds?

No: they're fixed at 5% bounce and 50 warmup, matching the platform's own risk lines.

What's the &ldquo;warmup score&rdquo;?

A 0–100 measure of your mailbox's warm-up progress. Under 50 means it hasn't warmed enough to safely send campaign volume.

What do I do about a high-bounce sender?

Clean the contact list, verify emails, and check Delivery Protection. High bounce is what burns domains and can auto-pause a campaign.

Can I click a card for more detail?

Yes: each card opens that mailbox's sent-email list for the analytics date range you've loaded.

Deliverability

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.

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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 ↗