Amazon Buyer-Seller Messaging has no API. Here is how to run it from one inbox anyway
Seller Central will copy every buyer message to an e-mail address you choose, and accept replies sent to the buyer's relay address. Read that mailbox, reply through the relay, keep the 24-hour clock, break no rules.
There is no messaging API
Every other marketplace in a multi-channel seller’s life has an inbox endpoint. Amazon does not. The Selling Partner API’s Messaging section lets you send a handful of templated, order-related messages (“your order is confirmed”, “we need a photo”), and that is all. It cannot list a buyer’s messages, read their text, or send a free-form reply. Sellers who want Amazon in the same inbox as their Mirakl marketplaces have been told, more or less, to keep a Seller Central tab open.
There is a supported way around it, and it has been there all along: e-mail.
How the mailbox route works
Seller Central can copy every buyer message to an e-mail address of your choosing. The copy carries the buyer’s relay address, an anonymised address at marketplace.amazon.co.uk, and if you reply to that address from an e-mail address Amazon knows, Amazon forwards the reply to the buyer and files it in the Buyer-Seller Messaging thread, exactly as if you had typed it in Seller Central.
- 1Buyer writesFrom the order page. Amazon anonymises both sides behind relay addresses.
- 2Seller Central copiesThe message lands in the mailbox set under Notification Preferences → Messaging, with the order number and item in the body.
- 3Inbox reads itOver IMAP: parse the order number, the item, the buyer's text; merge the Confirmation copy Amazon sends of your own replies.
- 4Inbox repliesOver SMTP to the relay address, from an address in Authorized Emails. Amazon forwards it and keeps the thread.
That is the entire integration. It is not glamorous, and it is not the SP-API, but it is Amazon’s own documented channel, it keeps every message inside Amazon’s system, and it means an Amazon buyer’s question sits in the same list as a B&Q customer’s, with the same clock running.
Setting it up in Seller Central
- A dedicated mailbox. A plain Gmail or Microsoft 365 account for this purpose only, with two-factor authentication and an app password for IMAP and SMTP. Do not reuse a person’s mailbox.
- Notification Preferences → Messaging. Set Buyer Messages, Confirmation, Delivery Failures and Opt-out notifications to the new address. Confirmation copies are what let the inbox show your own replies.
- Authorized Emails. Add the mailbox address, or Amazon will drop your replies to the relay.
- Keep a human on the list. If you remove your own address from the notification list while you set this up, nobody sees messages until the inbox is live. Add the tool’s address first, remove yours last.
The rules that still apply
| Criterion | Mirakl marketplaces | Amazon via mailbox |
|---|---|---|
| Response-time clock | Operator's business hours (usually) | 24 h wall clock, 7 days |
| Out-of-hours auto-acknowledgement | Allowed on most operators, policy-safe text | Not sent: automated buyer messages are restricted |
| Links, phone numbers, external e-mail | Rejected by most operators | Restricted by Amazon's communication guidelines |
| Attachments | Through the API | As e-mail attachments; Amazon forwards them |
| Your own reply visible in the inbox | Read back from the API | From the Confirmation copy, matched to the sent text |
| Orders and returns | Same API as messages | SP-API Orders (and returns reports), separate from messaging |
Two of those rows are the ones people get wrong. Amazon’s clock counts Saturdays, so a Friday-evening message is due Saturday evening: the three-clocks problem. And an automated courtesy reply, harmless on B&Q, is exactly the kind of message Amazon’s guidelines restrict; the right answer on Amazon is a person, on a rota, within the day. What SLA software has to do to make that rota visible.
Orders and returns: the API exists for those
What the SP-API does provide is orders: every order, its items, its state and its carrier, through the Orders API with a refresh token issued to your seller account. That is what turns a buyer message into a conversation with context: the item, the delivery date, whether it shipped. Returns and refunds come from the same place as reports rather than live endpoints. Together with the mailbox they give an Amazon channel the same three things a Mirakl channel has: the message, the clock, and the order beside it.
- The SP-API cannot read or reply to buyer messages; Seller Central's e-mail copies can.
- Read the notification mailbox over IMAP, reply to the relay address over SMTP from an Authorized Email; Amazon forwards and files it.
- Amazon's clock is 24 hours flat, weekends included, and automated buyer replies are restricted.
- Orders and returns do have an API; that is what gives the message its context.
Questions people ask
Can I read Amazon buyer messages through the SP-API?
No. The Selling Partner API has a Messaging API, but it only lets you send a small set of templated messages to a buyer about an order (for example a delivery confirmation or a request for information). It cannot read the buyer's messages or reply to them free-form. Reading and replying happens in Seller Central or through the e-mail copies Seller Central sends.
How do I get Amazon buyer messages into a help desk or shared inbox?
In Seller Central, under Notification Preferences → Messaging, set the e-mail address that receives Buyer Messages. Every buyer message is then copied to that mailbox with the buyer's relay address (something@marketplace.amazon.co.uk) as the reply-to. A tool that reads the mailbox over IMAP and sends replies over SMTP from an address listed in Authorized Emails can run the whole conversation; Amazon forwards the reply and keeps it in the thread.
Does an automatic reply count towards Amazon's 24-hour response time?
Automated replies to buyers are restricted under Amazon's communication guidelines, and a courtesy auto-reply does not satisfy the response-time metric. Growstall never sends an out-of-hours acknowledgement on Amazon channels for this reason.