DocsSending & testing

Send a test mail and schedule your campaign

The pre-flight checks that catch mistakes before your list sees them.

Last updated 27 July 2026 6 min read Sending & testing

Before you send

Every campaign in Sumezi goes through the same compose screen: subject and preheader, sender, recipients, and a pre-flight checklist that checks itself as you work. Nothing here is hidden behind a separate step — the checklist updates live while you type and as soon as you change your recipient list.

The checklist isn't a gate you have to clear before the send button lights up — it's a live status report. You can still click Send with red items showing; the real hard stops (missing SMTP, an over-quota send) happen at the server and are covered further down.

Step 1 — Write your subject and preheader

The subject field accepts up to 120 characters, but the counter turns to a warning color past 62 — that's roughly where most inbox lists start truncating. The preheader (the preview snippet next to the subject in an inbox) works the same way: 160 characters allowed, warning past 130.

Both live-preview instantly in the inbox mock-up and the full email preview on the right, so you see the truncation risk before it becomes real.

Step 2 — Confirm sender, recipients, and language

Your sender name and address come straight from Settings, Deliverability — Compose just reflects it. If nothing's configured yet, you'll see a note pointing you to Settings before you can send.

Recipients are either All subscribers or a specific list — each option shows its live subscriber count so you know exactly how many people you're about to reach. Suppressed and unsubscribed addresses are excluded automatically.

Language is currently single-version: the campaign sends in one language. A per-language split option is visible in the interface but marked as not yet built — don't rely on it.

Step 3 — Run the pre-flight checklist

Sumezi checks eight things every time you touch the subject, preheader, or recipient selection. Each item is either green or not — here's exactly what each one verifies.

CheckWhat it catches
Subject filledAn empty subject line — the send button won't stop you, but this is the one thing the confirm step itself refuses to skip.
Preheader filledA missing preview snippet, which leaves inboxes showing raw body text instead.
SMTP configuredNo sending server set up yet in Settings — this is a hard requirement for both test mails and real sends.
Sender configuredA missing from-name or from-email in your SMTP settings.
Recipients selectedAn empty audience — the chosen list or "All subscribers" has zero eligible people.
Unsubscribe link presentA template whose HTML has no {{unsubscribe_url}} merge tag or /unsubscribe link — checked against the actual template you're sending.
Quota availableYour plan's monthly send limit already used up by this campaign's recipient count.
Domain verifiedSPF, DKIM, or DMARC not fully verified for your sending domain — see the DNS setup guide.

The one real UI-level stop: the confirm step blocks you if the subject is empty, and (when scheduling) if the date/time you picked isn't strictly in the future. Everything else in the checklist is advisory — you can send with a missing unsubscribe link or an unverified domain if you choose to, though neither is a good idea.

Step 4 — Send a test mail first

The Send test mail button sits right above the checklist. It sends to your own account email address — there's no field to type in a different address here. It requires SMTP to be configured and a template already attached to the campaign; without one, you'll get a clear "campaign has no template yet" error instead of a silent failure.

Two things about test mails worth knowing: they deliberately skip the domain/routing check that blocks real sends (so a broken unsubscribe link shows up in your test inbox rather than being caught only after a real send), and they still count against your monthly send quota — a batch of test mails to a few colleagues is a real, countable send.

Personalization tokens like {{first_name}} render using your account's fallback text in a test mail, not your own name — the test uses a placeholder subscriber with only an email address, so don't be surprised by a blank greeting.

Step 5 — Send now or schedule

Switch to Schedule and you get a date and time field, plus a note that the time uses your workspace's timezone. Try to pick a moment that isn't strictly after right now, and the app stops you before it even opens the confirm modal.

Either way, clicking the main button opens a confirm modal with a summary — sender, recipient count, language, and the exact moment — plus a warning line listing any checklist items that aren't green yet.

Quota is checked twice for a scheduled campaign: once when you confirm, and again right before it actually fans out. If other sends used up your remaining quota in the meantime, the scheduled campaign doesn't just vanish — it's marked quota_blocked instead of failed, and you get a direct notification email explaining why it never went out.

What happens after you hit send

An immediate send shows a progress overlay with three steps — queued, sending, sent — and polls for real counts roughly every two seconds until every recipient has been processed. A scheduled campaign skips the progress bar entirely and just confirms the date, time, and recipient count you locked in.

Troubleshooting

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