Use cases

One primitive. Every agent shape.

Whatever your agent is, give it an address, a reply primitive, and a reputation. The use case lives on the other side of agent.onReply().

Use cases

Four agents. One primitive.

Every agent gets a working address, parsing, identity, and reputation in ~6 lines. The use case is whatever you put on the other side of agent.onReply().

inboundHi! Is Xavailable nextTuesday?— lead@acmereply.eventintent: schedule_demodate: 2026-05-14urgency: 0.8

Sarah

Support agent

auto-reply with intent

With classification enabled, inbounds arrive with intent + entities pre-parsed. Sarah's code reads `event.intent === "schedule_demo"` and replies with her calendar link in 30 ms — no regex, no LLM call on the hot path.

leadAmelia ParkVP Eng, Acme Cloudlast_post: agentscomposed at send timeSubject: agents at scaleBody: ref. your latest poston agent runtimes…▶ disclosed · unsub honored

Marcus

B2B sales agent

personalized + compliant outreach

Pulls lead context, composes subject + body per recipient at send time. Includes the required disclosure header and honors unsubscribes within 7 days (mails.ai AUP, modeled on Resend's). Reply intents (interested, unsubscribe, refer) close back into your CRM webhook with structured entities.

INVOICE.pdfattachment.parsedvendor: "Acme Cloud Inc"amount: 2_499.00 USDdue: 2026-06-15▶ webhook: erp.acme.com

Atlas

Document parser

invoice extraction from attachments

Inbound with a PDF runs your attachment handler. Atlas extracts vendor, amount, due_date, line items — a structured event lands on your ERP webhook. No OCR plumbing, no MIME wrestling, no PDF parsing libraries to maintain.

acme.com/signupEnter the 6-digit codewe just emailed you.9 4 7 2 0 6otp.extractedcode: "947206"from: noreply@acmeexpires_in: 540s▶ agent submits

Cipher

Browser agent

2FA codes across signups

When your browser agent signs your stack up for tools, mails.ai watches for the verification email, extracts the OTP into a structured event, and surfaces it through the SDK. Agent submits the code and continues the flow.

Plug intothe agent runtimes you already use
MCP server · REST · Webhooks
Claude Code· MCP serverCursor· MCP serverCline· MCP serverContinue· MCP serverWindsurf· MCP serverOpenAI Agents SDK· REST + SDKAnthropic SDK· REST + SDKLangGraph· TS / Py SDKMastra· TS SDKVercel AI SDK· TS SDKPydantic AI· Py SDKYour runtime· REST + Webhooks
Closed beta

Built for agents.
Self-serve at every volume.

Public API opens Q3 2026. Drop ~6 lines into your agent and ship.

npmpnpmbunpip
$ npm install @mailsai/sdk
Packages publish with cohort 1 · Q3 2026