The Nylas alternative for AI agents MailKite launches as an alternative to Nylas for AI agents, offering a scoped email address on a custom domain with parsed JSON delivery, eliminating the need for OAuth and mailbox sign-ins. The service targets developers building autonomous email agents that require their own address rather than operating a human's existing mailbox. The Nylas alternative for AI agents Nylas connects an agent to a human's existing Gmail or Outlook over OAuth, which is the right tool when the agent must act inside a real person's mailbox. Production means your own verified OAuth app, a CASA security review, token refresh, and a webhook that notifies with IDs so you go fetch the body. MailKite which we build gives the agent its own scoped address on a domain you control and pushes the parsed message as JSON. For developers wiring an autonomous email agent. The unit Nylas hands you is a grant : one authenticated connection to one human’s existing mailbox, reached over OAuth. That is exactly what you want when the agent’s job is to live inside a real person’s Gmail or Microsoft 365 account and act on their behalf. It’s a different shape from what an autonomous agent usually needs, which is its own address that nobody signs into. This post is the honest version of that split: where Nylas is the correct pick, what its agent path costs to stand up, and the 25 lines that are the whole MailKite side. Here’s the whole bring-your-own-agent loop on MailKite. Email in, verify the signature, hand the body to your model, reply through the same client. 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 = { // HMAC signature, replay window, constant-time compare — one call 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; // The body is untrusted INPUT, never instructions see the security section . 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 ; The agent gets a full, decoded message in one push. There’s no OAuth app to register, no mailbox to sign into, and no second API call to fetch the body. The identical handler shape exists for Python, Ruby, Go, PHP, and Java; see the receiving docs /docs/receiving and sending docs /docs/sending . A companion repo, demo-nylas-ai-agent https://github.com/mailkite/demo-nylas-ai-agent , has this running with a signed sample event you can fire; open it in StackBlitz https://stackblitz.com/github/mailkite/demo-nylas-ai-agent?file=server.mjs . Where Nylas wins for agents, honestly Nylas is not a send-first ESP wearing an inbound hat. It’s a bidirectional email, calendar, and contacts API, and it does one thing MailKite deliberately does not: it operates a human’s existing account . If the agent’s job is to read the actual mail sitting in someone’s Gmail or Outlook, reconcile it against their calendar, and reply from their real address, Nylas is built precisely for that. So this isn’t a “Nylas can’t do email” post. It does a great deal, and for the operate-a-real-person’s-mailbox job it’s the right call. The friction shows up when what you actually want is an autonomous agent with its own address that no human ever logs into. What Nylas asks of an agent builder The classic Email API path is: connect a mailbox, get told when something happens, then go read it. Concretely, that’s a hosted-OAuth code exchange to mint a grant, and a webhook that hands you IDs so you call the Messages API for the body. Here’s that path in Nylas’ own idiom from demo-nylas-ai-agent https://github.com/mailkite/demo-nylas-ai-agent , the nylas-contrast/ folder : python import Nylas from "nylas"; const nylas = new Nylas { apiKey: process.env.NYLAS API KEY } ; // 1 One-time per user: exchange the hosted-auth code for a grant you store. const { grantId } = await nylas.auth.exchangeCodeForToken { clientId: process.env.NYLAS CLIENT ID, code, // from your /callback after the OAuth redirect redirectUri: process.env.REDIRECT URI, } ; // Nylas refreshes the provider token for you from here on // 2 The webhook is a NOTIFICATION with IDs, not the message body. app.post "/nylas/webhook", async req, res = { res.sendStatus 200 ; // ack within ~10s, then work async const { type, data } = req.body; if type == "message.created" return; // you also have to handle message.updated const msg = await nylas.messages.find { // GET /v3/grants/{grant}/messages/{id} identifier: data.grant id, messageId: data.object.id, } ; const answer = await runAgent { task: msg.data.body } ; // untrusted input await nylas.messages.send { // sends AS the connected human's mailbox identifier: data.grant id, requestBody: { to: msg.data.from, subject: Re: ${msg.data.subject} , replyToMessageId: data.object.id, body: answer.html, }, } ; } ; The code is clean. What that snippet doesn’t show is the part that takes weeks, not minutes: Here’s the setup chain an agent’s own Nylas mailbox walks before it reads a single email, top to bottom: None of this is a knock if the agent is meant to run inside a person’s account . It’s exactly the wrong amount of ceremony if you just want agent@yourco.dev answering its own mail. The comparison, no adjective inflation | Nylas | MailKite | | |---|---|---| | The address | Federates a human’s existing Gmail/M365/IMAP Agent Accounts beta for an agent-owned one | Agent’s own scoped address on a domain you control | | Getting to production | Your own OAuth app + Google verification + annual CASA for restricted scopes | DNS-verify SPF+DKIM to send, MX to receive , no review | | Inbound delivery | Webhook notifies with IDs, you GET the message; body stripped over 1 MB | Full parsed message pushed as one signed JSON webhook | | Sender trust signal | Call the Messages API and read headers yourself | auth block SPF/DKIM/DMARC/spam in the payload | | Credential upkeep | OAuth grants Nylas refreshes; provider send caps Gmail ~2k/day | An API key; no per-mailbox OAuth or token refresh | | Free tier | 5 connected accounts, sandbox/testing only | 3,000 messages/mo, inbound + outbound | | Per-mailbox cost | ~$2.00 per connected account/mo over the included 5 Full Platform | No per-domain or per-address fee | | Who runs the loop | You | You, or a route with action: 'agent' | The through-line: Nylas wins when the agent must operate a real human’s existing mailbox, calendar, and contacts. MailKite wins when the agent should just have its own address , with the message pushed already-parsed and no OAuth app between you and the first email. What actually hits your agent’s webhook MailKite decodes the message at the edge, so your handler gets fields, not IDs to go fetch and not MIME to parse: { "id": "msg 2Hk9…", "type": "email.received", "from": { "address": "ada@example.com" }, "to": { "address": "agent@myapp.ai" } , "subject": "Re: invoice 1042", "text": "Looks good — approved ", "html": "