Deliverability suite

Sent isn't the metric. The inbox is.

Most providers report "delivered" and stop there. We instrument where mail actually lands — inbox, spam, or missing — per mailbox provider, and engineer every layer underneath it. Authentication, reputation, hygiene, and abuse control, on sending infrastructure we own.

Authenticate a domain Read the deliverability docs

North star: inbox-placement rate — measured, surfaced, alerted on.

<0.1%Complaint-rate guardrail, enforced per tenant
100%SPF + DKIM aligned for DMARC, by default
0Shared third-party pools — our IPs, our reputation
2 streamsTransactional and marketing never mix reputation
The pillars

Five layers between your API call and the inbox

Each one is a place mail goes to die at a lazy provider. We own all five.

Authentication & alignment

Auto-generated DKIM keys, derived SPF and DMARC, optional custom MAIL FROM, and a tracking-domain CNAME. One-click DNS publishing on our own fleet, copy-paste records for any registrar, and live re-verification. Alignment is a gate — we warn before you send on an unverified or misaligned domain.

Reputation & dedicated IPs

Dedicated IP pools for scale, pool-per-tenant or pool-per-stream, with transactional and marketing kept strictly apart. Automated warmup ramps volume per IP per day, auto-adjusting to engagement and bounce signals. A live reputation score per domain and per IP, with alerts before it slips.

List hygiene & suppression

Hard bounces and complaints auto-suppress, and the per-project suppression list is enforced pre-send — not after. Optional address validation checks syntax, MX, and disposable or role accounts before a message ever leaves. Search, export, and audit every suppression with a reason attached.

Inbox placement & monitoring

Seed-list tests send to accounts across major mailbox providers and report folder placement — inbox, spam, or missing — per provider. Continuous blocklist monitoring watches your IPs and domains against major RBLs, and DMARC aggregate reports are ingested and parsed so you can see exactly who's sending as you.

Abuse prevention

Signup screening with disposable-domain and risk scoring, send-pattern anomaly detection, and per-tenant caps that expand only as reputation is proven. Complaint-rate guards and a fast kill-switch keep one bad actor from poisoning the pool. On shared infrastructure this is existential — so we treat it as day-one, not later.

Compliance & standards

One-click unsubscribe per RFC 8058 with proper List-Unsubscribe headers, BIMI support once DMARC is at enforcement, and DMARC policy guidance that walks you from none to quarantine to reject. GDPR and CCPA ready, with data export and delete.

Bulk-sender rules

Google and Yahoo requirements, handled automatically

The 2024 bulk-sender rules disqualify a lot of senders. usermails meets every one before you hit send.

Requirement What it means How usermails handles it
SPF + DKIM aligned Both must pass and align for DMARC to authenticate the sending domain. Keys and records generated and verified at domain setup; alignment is checked on every send.
DMARC published A valid DMARC record is required for bulk senders. DMARC derived automatically with a guided path from p=none to enforcement.
One-click unsubscribe RFC 8058 — recipients must unsubscribe in a single click, honored within two days. List-Unsubscribe and one-click headers injected for marketing streams, processed instantly.
Complaint rate < 0.3% Stay under 0.3%, and never near 0.3% — aim below 0.1%. Real-time complaint-rate guards alert and throttle before you cross the line.
Valid forward & reverse DNS Sending IPs need matching PTR records and a real hostname. Managed on our own IP space — PTR, hostname, and TLS configured for every pool.

Targets: complaint rate under 0.1% (and always under the 0.3% hard ceiling). We surface the live number so you never find out from a deferral.

Our infrastructure

Built on sending infrastructure we own

Not a reseller, not a shared third-party pool. Dedicated IPs we control end to end — which means IP reputation is something we can actually manage on your behalf.

Full control of IP reputation

Because we run our own IP space, we set the warmup curves, isolate tenants, and rotate pools deliberately. Your sending reputation isn't shared with thousands of unknown senders on someone else's network.

Separated send streams

Transactional and marketing run on separate pools so a campaign can never drag down your password resets. Each stream warms and reports independently, with its own reputation score.

A cross-tenant moat

Observing placement and reputation signals across many tenants lets us route smarter, warm faster, and alert earlier than any single sender working alone can. Every send makes the next one more deliverable.

What you see

The metrics we surface to you

No black boxes. Every signal that determines placement is on the dashboard.

Inbox placement

Folder placement percentage by mailbox provider, from live seed-list tests.

Reputation score

Composite per-domain and per-IP score with trend lines and alerts.

Bounce & complaint

Live hard-bounce and complaint rates against the thresholds that matter.

Blocklist status

Continuous RBL monitoring for your IPs and domains, with listing alerts.

Auth health

DKIM, SPF, DMARC, and BIMI status, re-verified on a schedule.

Warmup progress

Ramp schedule and current per-IP capacity as a new pool warms.

DMARC reports

Parsed aggregate reports — who sends as you, and where alignment fails.

Delivery rate

Accepted-by-receiver rate, broken out by domain and by stream.

Stop guessing whether it landed.

Authenticate a domain in minutes, send through dedicated IPs we manage, and watch inbox placement on the same dashboard. Resend-compatible API — change the base URL and you're sending.

Start free Migrate from Resend

Postmark-grade deliverability. Resend-grade DX. On infrastructure you control.