The Mailjet alternative for AI agents MailKite launches an email API designed for AI agents, offering parsed JSON with SPF/DKIM/DMARC verification and a receive-reply loop, contrasting with Mailjet's Parse API which requires manual route setup and lacks a trust verdict. The service provides a webhook-based agent loop that verifies email signatures before processing, enabling autonomous email agents to act on trusted inbound mail. The Mailjet alternative for AI agents Mailjet a Sinch company can receive inbound mail through its Parse API, but you create the parseroute by hand, map its own field names, and there's no single trust verdict for the body. MailKite which we build gives an agent a real inbox: parsed JSON with an spf/dkim/dmarc block and a receive→reply loop. For developers wiring an autonomous email agent. Start from what an autonomous agent actually needs: its own scoped address, mail arriving as data it can read, and a signal telling it whether that mail can be trusted before it acts. Mailjet was built to send well, and its inbound path, the Parse API, is a capable bolt-on rather than an agent surface. This post is the honest version of that gap: where Mailjet wins, the exact inbound shape it hands you, and the roughly 20 lines that are the entire MailKite side. Everything below is a repo you can run while you read. Clone demo-mailjet-ai-agent https://github.com/mailkite/demo-mailjet-ai-agent and npm start , or open it in StackBlitz https://stackblitz.com/github/mailkite/demo-mailjet-ai-agent?file=server.mjs real Node in a browser tab, no account where it runs on load. You don’t need a domain to see the loop run: a webhook normally needs a public URL, so npm start boots the server and self-fires a correctly signed email.received event at its own localhost — the whole receive→verify→think→reply loop runs in one command the reply is a dry-run, and managed-route.mjs dry-runs the hosted path too . It also ships the Mailjet path next to it in mailjet-contrast/ , so every contrast here is something you can diff and test, not take on faith. A domain comes in only when you want real inbound email to arrive. Here’s the whole MailKite loop: email in, verify the signature, hand the body to your model, reply through the same client. This is the heart of server.mjs in that repo — the repo wraps it in a dry-run harness and a stub agent so it runs with no key and no LLM, but the loop is exactly this, and it runs as pasted on Node 18+ npm install mailkite express : python import express from "express"; import { MailKite } from "mailkite"; const app = express ; const mk = new MailKite process.env.MAILKITE API KEY ; const SECRET = process.env.MAILKITE WEBHOOK SECRET; app.use "/hooks/agent", express.raw { type: "application/json" } ; app.post "/hooks/agent", async req, res = { if MailKite.verifyWebhook req.headers "x-mailkite-signature" , req.body, SECRET { return res.sendStatus 401 ; } res.sendStatus 200 ; // ack fast; run the agent out of band const event = JSON.parse req.body ; if event.type == "email.received" return; // Body is untrusted INPUT, never instructions. Trust comes from auth, not From. const answer = await runAgent { task: event.text, from: event.from.address, trusted: event.auth.spf === "pass" && event.auth.dmarc === "pass", } ; await mk.send { from: event.to 0 .address, // reply from the address it was sent to to: event.from.address, subject: Re: ${event.subject} , inReplyTo: event.id, // threads the reply html: answer.html, } ; } ; app.listen 3000 ; That’s a fully autonomous email agent: it hears, thinks, and answers, with the trust decision made from the auth block instead of the forgeable From . npm start boots this server and self-fires the exact payload MailKite’s delivery worker sends, so in one command you watch the agent read the task, take its verdict straight off event.auth , and dry-run the reply — no account or LLM required. The same handler shape exists for Python, Ruby, Go, PHP, and Java; see the receiving docs /docs/receiving and sending docs /docs/sending . Where Mailjet wins for agents, honestly Mailjet is a real ESP with a real inbound story, and a few things genuinely count in its favor. What Mailjet asks of an agent builder Inbound on Mailjet is the Parse API, and the setup is deliberate: you create a parseroute with an API call. One POST /v3/REST/parseroute with a webhook Url returns an address on @parse-in1.mailjet.com or you can bind your own domain by pointing an MX record at parse.mailjet.com . Every inbound email to that address is then POSTed to your Url as application/json . The payload is Mailjet’s own field vocabulary, not a normalized one. You get Sender , Recipient , From , To , Cc , Subject , Date , a Headers object, a Parts array, Text-part and Html-part for the body, SpamAssassinScore , and attachments as base64 in AttachmentN fields. What you don’t get is a single trust verdict. There’s no spf , dkim , or dmarc field. The DKIM-Signature sits raw inside Headers , and if the agent’s decision to act depends on whether the sender is really the sender, that verification is your code. Here’s the honest inbound handler — it’s mailjet-contrast/handler.mjs in the repo, sitting right next to the MailKite server.mjs above so you can put them side by side: // Mailjet Parse API inbound: you create the parseroute, then map + verify yourself. import express from "express"; const app = express ; app.use "/mailjet/parse", express.json { limit: "30mb" } ; app.post "/mailjet/parse", req, res = { const m = req.body; // Mailjet's field names, not yours const email = { from: m.From, // "Ada