Sage 300 and Plaid integration

What moves between them

The main flow is Sage 300 into Plaid. ml-connector polls Sage 300 on a schedule tied to your payment cycle, reading APPaymentAndAdjustmentBatches and matching vendors from APVendors. Those batches are validated against Plaid-connected bank accounts, and approved batches are sent to Plaid as ACH transfer or wire transfer requests, allocated to the correct bank account. Plaid webhooks notify ml-connector when transfers complete or fail, and failed transfers are logged and marked for replay. Vendor master data flows bidirectionally so payment destinations remain in sync.

How ml-connector handles it

ml-connector stores Sage 300 HTTP Basic Auth credentials encrypted and includes them in the Authorization header on every request, polling the customer's IIS instance URL per tenant. It stores Plaid client credentials encrypted and presents them on every request, refreshing the Plaid bearer token when a call returns a 401. When a Sage 300 payment batch is ready, ml-connector maps each vendor and amount to a Plaid-connected bank account by matching vendor master records, then submits a transfer request with an idempotency key to prevent duplicate transfers if the request succeeds but the response is lost. Plaid's 24-month transaction history limit is respected by filtering on batch date. Transfer descriptions are truncated to Plaid's 15-character RTP and 10-character ACH limits. Every transfer carries a full audit trail and can be replayed if the downstream Plaid call fails or times out.

A real-world example

A mid-sized construction distributor runs Sage 300 on-premise for accounting and procurement and uses Plaid to connect to checking accounts at three regional banks. Before the integration, the accounts payable team reviewed payment approval batches in Sage 300, printed the list, opened their online banking portal for each bank, and manually entered recipient bank details and amounts from the printout. With Sage 300 and Plaid connected, approved payment batches flow from Sage 300 directly to Plaid, and ACH transfers are initiated automatically to the correct bank account without re-keying. The AP team now spends their time on vendor management instead of data entry.

What you can do

• •Read Sage 300 vendors and payment batches on a schedule and validate them against Plaid-connected bank accounts.
• •Initiate ACH and wire transfers from Plaid using Sage 300 payment batch data, allocated to the correct bank account.
• •Encrypt both HTTP Basic Auth and Plaid credentials, refresh tokens on demand, and prevent duplicate transfers with idempotency keys.
• •Receive Plaid transfer completion and failure webhooks with JWT signature verification and update transfer state in Sage 300.
• •Track every payment record from Sage 300 through Plaid transfer initiation with full audit trail and replay capability on failure.

Questions

Which direction does data move between Sage 300 and Plaid?

The main flow is Sage 300 into Plaid. Payment batches and vendor records move from Sage 300 into Plaid for ACH or wire transfer initiation. Plaid webhooks notify ml-connector of transfer completion or failure, and that status is reflected back in Sage 300's audit log. Vendor master data is aligned bidirectionally so payment destinations stay in sync.

How does the integration handle Sage 300's HTTP Basic Auth and Plaid's client credentials?

ml-connector stores both credential sets encrypted. Sage 300 credentials are included in the HTTP Authorization header on every request using base64 encoding. Plaid credentials are submitted as custom headers (PLAID-CLIENT-ID and PLAID-SECRET) or request body fields. When Plaid returns a 401 response, ml-connector refreshes the bearer token and retries the request automatically.

Does Plaid's idempotency key requirement need special handling?

Yes. ml-connector generates a unique idempotency key for each transfer request using the Sage 300 batch ID and vendor ID. Plaid uses this key to deduplicate requests for 48 hours, so if a transfer request succeeds but the response is lost, retrying with the same key will not create a duplicate transfer. Keys are stored in the audit trail and expire after 48 hours.