Brevo bundles marketing, transactional sending, and an inbound parser. MCPmailer is the mailbox, thread, and MCP surface an agent needs.
Transactional email APIs · Brevo claims checked July 2026
Brevo, formerly Sendinblue, is a broad marketing and transactional platform with a usable free tier of about three hundred emails a day, a clean REST API with SDKs in most languages, and a ready-made inbound parser so replies can come back into your application.
If you want campaigns, automations, a CRM, and transactional sending under one bill, Brevo covers a lot of ground cheaply. Its free daily allowance is also generous for a product that is mostly sending notifications.
The inbound parser is where the comparison gets specific. Brevo hands you a parsed message; we hand the agent a mailbox that already owns the thread, the history, and the search index, reached over MCP with no webhook to host.
Parsed inbound solves decoding. It does not answer which conversation this belongs to, what was already promised, or whether this person asked to be left alone. Those are the questions an agent has to answer before it replies, and they need stored state.
Three hundred a day is one number applied to everything. Ours splits by intent: replies into an inbound thread are near-unrestricted while first contact with a stranger is gated, which is the control you want when a model is picking recipients.
A platform built for campaigns makes it easy for an agent to do something you would rather it could not. We cap recipients at five per message and refuse bulk outright, which is a smaller product and a much smaller blast radius.
Every row is a claim we could defend with their documentation open beside it. Where they are ahead, the row says so.
Split by what the mail is for, which also keeps the reputations apart.
Campaigns and notifications stay
Lists, templates, and automations are not things we do.
Agents get their own subdomain
So agent sending cannot affect your marketing delivery.
Retire the parser webhook
For agent addresses only: threading, storage, and search come with the mailbox.
Yes, and it is one of the easier parsers to start with. You then own thread matching, storage, search, per-agent identity, and the wake-up mechanism, which is the part we ship.
Its daily allowance is higher, at roughly 300 a day against our 100. Ours includes receiving, threading, search, and three agent inboxes, so compare what you get rather than the number.
Yes. We have no campaign features at all, and a five-recipient cap per message makes bulk impossible on purpose.
No. Email, contacts, notes, and a vault only.
Keep your transactional sender for the mail your product sends. This is for the addresses your agents converse from, which is a different job with different failure modes.
The free tier is 3,000 emails a month across three agent inboxes, no card, with receiving, threading, and search included. Enough to watch a real conversation happen before you decide.
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