Sage 50 and ServiceTitan integration

What moves between them

The main flow is from ServiceTitan into Sage 50. ServiceTitan vendor bills, purchase orders, and vendor records flow into Sage 50 as accounts payable transactions, with amounts mapped to the correct GL accounts. ServiceTitan job and invoice data can also map to Sage 50 customer records and sales transactions. Customer and vendor reference data is kept aligned in both systems so that service work billed in ServiceTitan maps to the correct customer in Sage 50, and procurement through ServiceTitan vendors updates Sage 50 accounts payable without re-keying.

How ml-connector handles it

ml-connector runs on a Windows machine with the Sage 50 SDK installed and direct access to the company data file. It authenticates to ServiceTitan using OAuth2 client credentials and stores them encrypted. When ServiceTitan webhooks arrive for invoice.created or purchase.created events, ml-connector decrypts the credentials, connects to the local Sage 50 SDK with the Windows-local username and password, and writes the transaction into the corresponding Sage 50 module (accounts payable for vendor bills, accounts receivable for customer invoices). Because Sage 50 requires exclusive access to the data file and has no interactive session active during integration, ml-connector manages the connection lifecycle carefully and closes the SDK session after each write. ServiceTitan rate limits apply, so ml-connector respects the 60 calls per second per tenant quota and backs off on 429 responses. Every record carries the ServiceTitan transaction ID so replays are idempotent, and a full audit trail records the mapping from ServiceTitan invoice to Sage 50 general journal entry.

A real-world example

A plumbing and HVAC contractor with three field technicians uses ServiceTitan to schedule jobs, dispatch crews, and invoice customers in real time. They run Sage 50 US edition on a desktop at the office to manage vendor accounts, AP, and accounting. Before the integration, the office manager entered each day's invoices from ServiceTitan into Sage 50 by hand, then matched vendor bills as they arrived, a process that took two hours per week and caused month-end reconciliation delays. With ServiceTitan and Sage 50 connected, each customer invoice posts to Sage 50 automatically at job completion, and vendor bills from material suppliers sync in without re-keying, so the accounting records are ready for close the moment the month ends.

What you can do

• •Sync ServiceTitan vendor bills and purchase orders into Sage 50 accounts payable with GL account mapping.
• •Keep customer and vendor reference data aligned across ServiceTitan and Sage 50 so invoices and bills post to the correct accounts.
• •Receive ServiceTitan webhook events for invoices, payments, and vendors, with automatic retries and a full audit trail.
• •Authenticate Sage 50 via the Windows SDK and ServiceTitan via OAuth2 client credentials, with encrypted credential storage.
• •Map ServiceTitan amounts and line items to Sage 50 GL accounts and run on a schedule or in real time when webhooks arrive.

Questions

How does ml-connector access Sage 50 if it has no REST API?

ml-connector runs on a Windows machine with the Sage 50 SDK installed and direct access to the company data file. It authenticates to Sage 50 using the Windows-local username and password configured in the Sage 50 user database, plus the ApplicationID and company data file path (for US edition) or accdata directory path (for UK edition). The integration maintains exclusive access to the data file, so no interactive Sage 50 session can be active at the same time.

Which direction does data move between Sage 50 and ServiceTitan?

The main flow is from ServiceTitan into Sage 50. ServiceTitan vendor bills, purchase orders, invoices, and payments flow into Sage 50 as AP and AR transactions, mapped to the correct GL accounts and customers. Customer and vendor reference data is aligned in both directions so that field service work billed in ServiceTitan maps to the correct customer account in Sage 50.

How does ml-connector handle ServiceTitan's 60-calls-per-second rate limit and OAuth2 token refresh?

ml-connector respects the 60 calls per second per tenant quota and backs off with exponential retry when ServiceTitan returns a 429 rate-limit response. It caches the OAuth2 token for its full 900-second lifetime and only requests a new one when a call returns 401 or the token approaches expiry, avoiding redundant authentication requests.