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Open email infrastructure · API · CLI · MCP

Email for agents and humans.

Infrastructure you can read, run, and audit — with the provider's own response behind every message, so a person or a machine can see where it went and why.

Start sendingRead the docs

Free for 3,000 emails a month · no card

Sending in production for

  • Behnke Logistics
  • Hello Storage
  • Biofuse
  • Kalamazoo Excavation
  • Mule Box Portable Storage
  • The Foundry Kalamazoo
  • Treystar

and more

  • Named production customers7
  • Event types, all queryable8
  • Signed webhook events6
01 · Newsletters

Newsletters for a business with actual customers.

Most companies sending with Outsend are not software companies. They are an excavating contractor, a storage operator, a venue — people with a list, something to say once a month, and no interest in becoming a deliverability expert. The campaign side is built for them, and it is cheaper than what they were paying.

Write it, send it, see who actually got it.

Import the list you already have, build the email, send to all of it or part of it. You are billed for emails sent, not for contacts stored — so a list you mail once a month does not cost what a list you mail daily costs.

  • Bring your list · CSV import that carries your unsubscribes across, so nobody who opted out hears from you again.
  • Segments and templates · Mail part of the list without exporting it first, from a template you set up once.
  • Warm-up ramps · A new sending domain steps up over days instead of mailing everyone at once, which is the usual reason a first campaign lands in spam.
  • One-click unsubscribe · Hosted, handled, and suppressed across every future send — including your transactional mail.
Newsletters for small business

Campaigns

Marketing email sent from mail.acme.com

New campaign
AllScheduledSendingSent
NameStatus
  • Autumn collection launchWarm-up · day 2 of 4Sending
  • October product updateChecks passedScheduled
  • Weekly digest #37Paused by PriyaPaused
  • VIP early accessList cleaned before sendSent
02 · Agents

Agents are first-class citizens.

Software that has to prove its own work needs more than a one-word verdict. An agent cannot act on “delivered” — it needs the evidence, the uncertainty, and a gate before it changes anything that matters.

API, CLI, and MCP with verifiable outcomes.

So all three surfaces are built to the same rule: return what happened, what it was derived from, and what you could not determine. Reading and diagnosing run freely. Changing things is gated on a human.

  • API · World-class primitives. Stable, composable endpoints for sending, events, domains, and reputation controls — with idempotency keys, readable errors, and the provider's response on every event.
  • CLI · Operational leverage. Scriptable setup, inspection, replay, migration, and diagnostics. Everything you can do by clicking, available to a shell script, a runbook, or a CI job.
  • MCP · Native agent access. An MCP server agents connect to directly: send, inspect traces, explain failures, and propose remediation with structured, explainable outcomes.
How the agent surfaces work
03 · Start sending

One request, or the SMTP settings you already have.

A REST API with idempotency keys and honest rate limits, plus an SMTP relay that accepts whatever mailer you are already using. Verify a domain, send, then go read the trace.

Replay-safe, and limits you can read.

Retries do not duplicate mail, and a limit is never a silent drop.

  • Idempotency · Replay-safe for 24 hours. Retries do not duplicate mail.
  • Rate limits · 60/min and 1,000/hour per key — returned as a 429 you can read, never a silent drop.
Read the docs
# Send a transactional email
curl -X POST https://app.getoutsend.com/api/v1/emails \
  -H "Authorization: Bearer $OUTSEND_API_KEY" \
  -H "Idempotency-Key: order-8421" \
  -d '{
    "from": "Acme <hello@mail.acme.com>",
    "to": ["maya@example.com"],
    "reply_to": "support@acme.com",
    "subject": "Your order is on its way",
    "html": "<p>Hi Maya, it shipped!</p>"
  }'

Martin Business Consultants built Outsend for its own production sending, then productised it. It is funded by customers paying for cloud and support — which is a slower way to build a company and a much better way to build infrastructure.

Show your work.Martin Business Consultants
04 · Observable sending

“Delivered” is a summary. We keep the sentence it came from.

Acceptance is not delivery, and an aggregate percentage cannot tell you which. Every event Outsend records keeps the provider's own response — the SMTP code, the reason, the reporting host — so a person or an agent can explain what happened rather than guess.

Six events, one schema

Each endpoint gets its own HMAC secret and its own delivery log — attempts, response codes, response bodies. When a webhook fails, you can see that too.

  • email.delivered
  • email.bounced
  • email.opened
  • email.clicked
  • email.complained
  • email.unsubscribed
05 · Reputation sovereignty

Your reputation is yours. No neighbour can burn it.

On a shared pool, the worst sender sets everyone's ceiling. Outsend scores reputation per domain and per workspace, and when a sender crosses the line we stop them — automatically, before their behaviour becomes your bounce rate.

  • Sending runs on AWS-backed infrastructure with your own verified identity: DKIM, SPF, and DMARC against your domain, in the region you choose.
How domain verification works
06 · The standard

Four things a sending platform should be able to prove.

Not four features. Four claims we are willing to be held to, each with something you can go and check.

07 · Where trust is expensive

We started where getting it wrong is worst.

Outsend carries production sending for workloads where an unexplained failure is not an inconvenience. Same trust stack, three versions of the same enemy.

Highest trust barHealthcare and medicalEnemyBlack-box handling of sensitive communications, thin auditability, and unclear operational responsibility.MessageAuditable, observable sending on isolated infrastructure. Every event explainable, infrastructure inspectable, incidents disclosed, BAA available on Dedicated.Read moreMission-sensitiveNonprofitsEnemyPer-email pricing and growth economics that tax mission-driven communication.MessageA sustainably priced platform that does not turn mission-driven communication into a margin target.Read moreTime-sensitiveLogistics & shippingEnemyDowntime and opaque delivery that can interrupt the real-world movement of goods.MessageObservable infrastructure with per-provider evidence, incident clarity, and agent-ready remediation. A written SLA is available on Dedicated; there is no public one yet.Read more

We name the companies happy to be named, and say nothing at all about the regulated workloads. Trust-sensitive mail does not become case-study material.

08 · The long game

Never venture-backed. No acquisition clock.

There is no exit clock here, and no quarter where reliability loses to growth. That is not a grievance about venture capital; it is a statement about what our incentives reward.

  • Agents are first-class citizens. API, CLI, and MCP with verifiable outcomes.
  • Show your work. See where every email went — and why.
  • Your reputation is yours. No neighbour can burn it. No vendor owns it.
  • We're playing the long game. Never VC. Paid alignment.
Read the manifesto
Our transparency methodologyThe method, before the numbers.Get startedFree for 3,000 emails a month · no card

Ready to see where your email goes?

Free for 3,000 emails a month. No card to start, and everything we claim is checkable.

Start sendingRead the docs

Never venture-backed · operated by Martin Business Consultants