// everything in the box

Every feature you'd build
if you had the quarter.

Idempotent sends, typed SDKs, streaming events, reputation monitoring, inbound parsing, dedicated IPs, SOC 2 infrastructure — the stuff that takes other vendors a roadmap year. It ships in every plan.

Uptime / 12mo

99.993%

tracked publicly

Median send

187ms

API → SMTP accepted

Regions

6

US · EU · APAC

Monthly volume

2.4B

sent in Q1 2026

Shipping email for teams at

KeelhaulPeddlebeeTerraflowCargodropFolder.soMeadowplayZendenoBluebell
// send

One endpoint.
Every send shape.

Transactional, marketing, receipts, one-offs, bulk batch, React components rendered at send time — the same POST /v1/email handles all of it.

  • Idempotency keys

    Every key cached for 24h. Retry a thousand times, deliver exactly once.

  • Batch sending

    Up to 100 recipients per request, individually tracked, single atomic call.

  • Scheduled delivery

    Pass scheduled_at; we queue and fire to the minute.

  • Attachments up to 40MB

    base64 or pre-signed URL, MIME types you pick.

  • Tags & metadata

    Up to 10 tags, 40 metadata fields. Filter logs, slice analytics.

POST /v1/email
// One call. Typed response. Retries built in.
const { id, status } = await volt.send({
  from:    'team@acme.dev',
  to:      ['dev@customer.io'],
  subject: 'Your receipt #4827',
  react:   <Receipt order={order} />,
  tags:    ['billing', 'receipt'],
  metadata: { order_id: order.id, plan: 'pro_plus' },
  idempotencyKey: `receipt:${order.id}`,
});
 
// → { id: "em_01HQ7X9KVZT…", status: "queued" }
// templates

Write emails in
React.

Ship .tsx files alongside your product code. Components render on our edge at send time into bulletproof HTML — tested in 90+ email clients. No separate template system. No WYSIWYG.

  • React Email primitives

    Button, Section, Preview. Tailwind classes compiled down to inline styles.

  • Dark-mode aware

    Media query + meta tags handled for Gmail and Apple Mail.

  • Live preview in the dashboard

    Render any commit against real data. Diff two versions.

  • Handlebars for non-React codebases

    Same template library, template-as-string, same API.

  • MJML support

    Bring existing templates. We compile at ingest, cache the result.

preview — order-receipt.tsx

Thanks for your order, Morgan

Order #4827 · May 12, 2026

Billed to •••• 4242

Pro+ plan (monthly)$29.00
Overage · 12,400 emails$0.00
Total$29.00
// events & webhooks

Every state change,
signed and streamed.

Delivered · Opened · Clicked · Bounced · Complained · Deferred · Unsubscribed · Queued · Rejected. Nine event types, HMAC-signed payloads, exponential retry, dashboard replay.

  • HMAC-SHA256 signing

    Verify X-VoltMail-Signature; rotate secrets without downtime.

  • Retry with backoff

    5 attempts over 3 hours, then dead-letter queue you can replay.

  • Replay from dashboard

    Pick a date range, pick events, replay to any endpoint.

  • Event filtering

    Subscribe per-endpoint to only the events you need. No noise.

  • TypeScript schemas

    Zod-validated payloads bundled with the SDK.

events — livestreaming
deliveredteam@acme.dev → ops@cargodrop.ioem_01HQ7XD88LG
unsublist-unsub · one-clickem_01HQ7XAB2MN
bouncedsmtp 550 5.1.1 · user unknownem_01HQ7XBPQ4S
complainedabuse@aol.com · feedback loopem_01HQ7XE4K1J
deferredsmtp 451 · greylistem_01HQ7XCFD2W
deliveredteam@acme.dev → ana@peddlebee.coem_01HQ7XAB2MN
clickedhttps://acme.dev/r/4827302
openedbeacon · em_01HQ7X9KVZT204
// custom domains

DNS that verifies
itself.

Paste your domain. We generate SPF, two rotating DKIM selectors (2048-bit), MX, DMARC, and optional BIMI records. Copy them once; we re-check every 5 minutes and alert the moment something drifts.

  • Auto-rotating DKIM

    Two selectors swap quarterly. Zero-downtime key rotation.

  • DMARC report ingestion

    We parse forensic + aggregate reports, surface failures.

  • BIMI & VMC support

    Serve your logo in inboxes that render it.

  • Click & tracking subdomains

    links.acme.dev so open/click URLs wear your brand.

  • Subdomain isolation

    Warm marketing. separately from receipts.

dashboard — domains/acme.dev
TYPEHOSTVALUESTATUS
TXT_voltmail.acme.devv=voltmail1;k=rsa…✓ verified
MXacme.dev10 mail.voltmail.dev✓ verified
TXTacme.devv=spf1 include:_spf…✓ verified
CNAMEvolt._domainkey.acme…volt.domainkey.voltmail.dev✓ verified
CNAMEvolt2._domainkey.acm…volt2.domainkey.voltmail.dev✓ verified
TXT_dmarc.acme.devv=DMARC1; p=quarantine; rua=…✓ verified
TXT_bimi.acme.devv=BIMI1; l=https://acme…⧗ pending
SPF alignedDKIM 2048-bitDMARC p=quarantine
// api keys

Scoped keys.
Zero-downtime rotation.

Separate live from test. Separate read from send. Rotate without a deploy. Audit who used what, last.

  • Permission scopes

    send:write, logs:read, domains:admin, etc.

  • IP allowlists

    Bind a key to specific CIDR ranges.

  • Rate limits per key

    Protect production from runaway scripts.

  • Last-used tracking

    Find stale keys. Revoke with a click.

  • Audit log

    Every key action (create, rotate, revoke) recorded, exportable as CSV.

dashboard — api keys
  • prod-apiLIVEsend:writevm_live_•••••• 7a2f
  • prod-logsLIVElogs:readvm_live_•••••• 3c91
  • ci-testsTESTsend:writevm_test_•••••• b4e2
  • webhooks-adminLIVEwebhooks:adminvm_live_•••••• 9d05
  • legacy-migrationREVOKEDvm_live_•••••• e118
5 active · 1 revoked · rotated 12d ago
// deliverability

Reputation as a
live metric.

Most vendors treat inbox placement like a state secret. We plot your reputation at Gmail, Microsoft, Yahoo, and 14 other major ISPs, live. See a dip, see the cause, fix before the bounce rate does.

  • Per-ISP reputation scoring

    Live, not lagged 24h like Postmaster Tools.

  • Dedicated IPs on Pro Max

    With automated warmup (starting at 50 then doubling).

  • Suppression lists

    Global + per-account, auto-maintained. Bounce → suppressed in ≤60s.

  • List-Unsubscribe + one-click

    Gmail/Yahoo 2024 requirements handled out-of-box.

  • Google Postmaster integration

    Connect once. We ingest and plot daily.

reputation — last 30d
100908070
Gmail · 98.4 Microsoft · 95.2 Yahoo · 93.1
// logs & search

Every email,
searchable for 90 days.

Full-text search across subject, headers, recipients, tags, metadata. Filter by event, by date, by status. Click a row to see the full message timeline.

  • Per-recipient timelines

    Every touch point for user@example.com, chronologically.

  • SMTP-level traces

    The actual 220/250/550 conversation with the receiving MTA.

  • CSV export, unlimited

    For accounting, audit, analytics. No row caps.

  • Saved queries

    Your common "show me last week's bounces on the receipts domain" — one click.

  • Raw message retrieval

    Pull the exact MIME we sent. For debugging, for compliance.

logs — search
q:to:dev@customer.ioANDstatus:bounced
last 7d ▾
  • bounceddev@customer.io · Your receipt #48272m ago
  • bounceddev@customer.io · Password reset6h ago
  • bounceddev@customer.io · Invoice available1d ago
  • bounceddev@customer.io · Welcome to Acme2d ago
  • bounceddev@customer.io · Trial ending4d ago
  • bounceddev@customer.io · Sprint recap6d ago

6 results · 112ms · export CSV →

// the rest

The details that
close the ticket.

A short list of the not-so-small things that tend to matter on day 90, not day 1.

Inbound email parsing

Receive, parse, and stream replies as structured JSON — headers, stripped signatures, attachments, threaded history. Build support desks in an afternoon.

MIMEattachmentsthreading

Teams + RBAC

Owner, admin, member, viewer. Per-workspace roles, per-project scopes. SCIM + SSO on Enterprise. Invite flows with email + Slack.

SSOSCIMSAML

Multi-workspace

One account, N workspaces. Separate sending, separate billing, separate people. Great for agencies, portfolios, client work.

isolationbillingswitcher

Multi-region send

Pin sends to us-east, us-west, eu-west, eu-central, ap-southeast, ap-northeast. Data residency on Pro+ and above.

GDPRdata residency

A/B testing

Split sends by subject, template, from-name, send time. Auto-selects winner by open / click / convert. Multi-arm bandit optional.

multivariatebandit

Email validation

MX + SMTP probe + catch-all detection before you send. Included, not a $0.004 add-on.

syntaxmxsmtp

Suppression management

Global + list-level suppressions. Import CSV from your old provider. Export yours — no lock-in.

importexport

Scheduled & recurring

Send at 2026-05-12T09:00Z. Or set a cron: 0 9 * * 1. Cancel in flight from the dashboard.

croncancellable

Bulk sending API

Up to 100 personalized emails per call, 500 calls/sec on Pro Max. Each tracked individually. Queue-backed, retryable.

batchqueue
// security & compliance

Legal's checklist,
already signed.

We hand procurement a folder, not a conversation. SOC 2, ISO, GDPR, HIPAA, sub-processors list, pen test reports — linked, dated, current.

SOC 2

Type II

ISO 27001

Certified

GDPR

DPA included

HIPAA

BAA available

CCPA

Compliant

PCI-DSS

SAQ-A

AES-256

At rest

TLS 1.3

In transit

Pen tests

Quarterly

Bug bounty

Public scope

99.99% SLA

Pro Max

Audit logs

Export API

Your stack doesn't need
another meeting.

Everything on this page ships in the Free plan. Start now. Pay when you scale. Or never.

Create account →Compare plans