Sage 50 and Amazon Seller Central integration

What moves between them

The main flow runs from Amazon Seller Central into Sage 50. ml-connector reads settled orders and the financial events tied to them, then posts each sale as a Sage 50 sales invoice and the marketplace fees, refunds, and reimbursements as Sage 50 journal entries against the right accounts. The authoritative source for payouts is the Amazon settlement report, so disbursement reconciliation is driven from there rather than from unsettled events. In the other direction, Sage 50 inventory item quantities flow out to Amazon listings so the stock advertised on the marketplace reflects what Sage 50 holds. Cadence follows your Amazon settlement and fulfillment rhythm: orders and inventory poll more often, settlements process as each statement closes.

How ml-connector handles it

ml-connector stores both credential sets encrypted. On the Amazon side it exchanges the LWA refresh token for short-lived access tokens, caches them, refreshes them before the one-hour expiry, and passes the marketplace_id and region on every call since Amazon does not infer them. On the Sage 50 side a local Windows agent opens an exclusive SDK session with the Sage user name and password, so the customer must keep the machine on and logged in and must not have Sage 50 open interactively under the same user. Because Sage 50 has no inbound endpoint and Amazon delivers events only through EventBridge or SQS, the integration polls Amazon on a schedule and follows the NextToken cursor through every page rather than relying on a push. Each Amazon Seller SKU is mapped to a Sage item, and Amazon fee and refund types are mapped to Sage GL or nominal accounts so every posting lands on a valid account. Settlement is asynchronous, so payouts and fees post only after Amazon releases the settlement report, which the agent creates, polls until done, and downloads from the presigned S3 URL. Sage 50 has no idempotency key, so before creating an invoice the agent checks for an existing record by its Amazon order reference and dedupes on a stored jobId so a re-read order is not booked twice. Amazon returns HTTP 429 under its token-bucket limits, so the connector backs off with jitter, and every record carries a full audit trail and can be replayed if a Sage 50 write fails. The agent SDK version must match the installed Sage 50 year version.

A real-world example

A consumer-goods seller with around 25 staff sells through both a local trade counter and an Amazon storefront, and runs Sage 50 on a PC in the back office. Before the integration, a bookkeeper downloaded the Amazon settlement report every two weeks and hand-keyed the gross sales, referral and fulfillment fees, and refunds into Sage 50, while warehouse staff updated Amazon stock counts separately. Month-end stalled while finance reconciled the Amazon payout against what had been entered, and oversells happened when Sage 50 and Amazon inventory drifted apart. With Sage 50 and Amazon Seller Central connected through the local agent, settled orders post as sales invoices, fees and refunds post as journal entries against the right accounts, the payout reconciles against the settlement report, and Sage 50 inventory counts push out to Amazon listings so advertised stock stays accurate.

What you can do

• •Post settled Amazon Seller Central orders into Sage 50 as sales invoices without re-keying.
• •Record Amazon marketplace fees, refunds, and reimbursements as Sage 50 journal entries against the correct accounts.
• •Reconcile each Amazon payout using the settlement report as the authoritative disbursement source.
• •Push Sage 50 inventory item quantities out to Amazon listings so advertised stock stays current.
• •Bridge the Amazon LWA refresh token and the Sage 50 SDK user login through a local agent, polling on a schedule with retries and a full audit trail.

Questions

Which direction does data move between Sage 50 and Amazon Seller Central?

The main flow is from Amazon into Sage 50: settled orders post as sales invoices and marketplace fees, refunds, and reimbursements post as journal entries against the right accounts. In the other direction, Sage 50 inventory item quantities flow out to Amazon listings so advertised stock matches what Sage 50 holds. Sage 50 is the accounting system of record, so ml-connector does not write payout data back into Amazon beyond the inventory it pushes to listings.

How does the integration connect if Sage 50 has no cloud API?

Sage 50 is desktop software with no REST API, so ml-connector runs a small local Windows agent on the same machine as the Sage 50 install and talks to it through the .NET SDK on the US edition or Sage Data Objects on the UK edition. The agent signs in with a dedicated Sage 50 user name and password and holds an exclusive session on the company file, which means the machine must stay on and logged in and Sage 50 must not be open interactively under that same user. The agent then syncs data to and from Amazon over HTTPS.

How are Amazon settlements and fees handled so the books reconcile?

Amazon financial events appear at the event level right away, but the settlement report is the authoritative record of what Amazon actually pays out. ml-connector drives payout reconciliation from the asynchronous Reports API settlement data, which it creates, polls until done, and downloads, then posts the captured sales, fees, refunds, and reimbursements to mapped Sage 50 accounts. This keeps the Sage 50 ledger aligned with each Amazon disbursement rather than with unsettled activity.