Sage 50 and ADP integration

What moves between them

The main flow runs from ADP into Sage 50. After each payroll run, ml-connector reads ADP's general ledger documents and posts the labor cost journals into Sage 50 as GL journal entries, mapped to the matching Sage 50 accounts. Worker records flow the same direction so the Sage 50 employee list reflects ADP hires, terminations, and rehires. ADP cost centers, departments, and job codes are mapped to Sage 50 GL accounts and project or department codes so every journal line lands on a valid account. ADP general ledger documents are read-only, so ml-connector never writes financial entries back into payroll. The cadence follows your payroll calendar, since neither side pushes finance events.

How ml-connector handles it

Because Sage 50 has no cloud API, ml-connector runs a local agent on the Windows machine where Sage 50 is installed. The agent uses the .NET SDK or SDO with a dedicated Sage user name and password, and must run in an interactive desktop session, so the machine stays on and logged in for syncs to run. The agent holds the company file in a single exclusive SDK session, so the integration user should not be logged into Sage 50 interactively at the same time. On the ADP side, ml-connector stores the OAuth2 client credentials and the client certificate encrypted, presents the certificate at the TLS layer on every request, and refreshes the ADP bearer token when a call returns 401. Sage 50 has no webhooks, so ADP general ledger documents and worker data are polled on a schedule tied to your payroll calendar; ADP event notifications can supplement this where they are enabled. Cost centers and departments are mapped first, so every payroll journal line references a Sage 50 account that already exists. Before creating a Sage record, the agent checks for an existing match by reference number to avoid duplicates, since the SDK has no idempotency key. ADP rate limits return HTTP 429 per gateway node, so ml-connector backs off and retries, and it tracks the ADP certificate expiry so a renewal does not turn into an outage. The Sage SDK version must match the installed Sage 50 year version, so a Sage upgrade is paired with an agent update. Every record carries a full audit trail and can be replayed if a write fails.

A real-world example

A small contract manufacturer with about 60 employees runs Sage 50 on an office server for its books and uses ADP Workforce Now for payroll. Before the integration, the bookkeeper exported the payroll register from ADP every pay period and typed the wage, tax, and benefit totals into Sage 50 as a manual journal, then reconciled headcount against the employee list by hand. With Sage 50 and ADP connected, a local agent posts each payroll run's general ledger document into Sage 50 automatically, split to the right accounts, and worker changes keep the two lists aligned. Payroll posting takes no manual entry, and month-end starts with the wage accounts already reconciled.

What you can do

• •Post ADP payroll general ledger documents into Sage 50 as GL journal entries after every pay run.
• •Keep the Sage 50 employee list aligned with ADP hires, terminations, and rehires.
• •Map ADP cost centers, departments, and job codes to Sage 50 GL accounts so payroll lands on valid accounts.
• •Bridge ADP OAuth2 with its required mutual TLS certificate to the local Sage 50 SDK login.
• •Run a local agent on the Sage 50 machine and poll on your payroll schedule, with retries and a full audit trail on every record.

Questions

Which direction does data move between Sage 50 and ADP?

The main flow is ADP into Sage 50. Payroll general ledger documents and worker records move from ADP into Sage 50, while cost centers and departments are mapped so journal lines land on valid accounts. ADP general ledger documents are read-only, so ml-connector does not write financial entries back into payroll.

Why does the Sage 50 side need a local agent?

Sage 50 is desktop software with no cloud REST API, so it can only be reached through a local SDK on the same Windows machine. ml-connector runs a small agent there that uses the SDK with a dedicated Sage user name and password and syncs to the cloud over an encrypted connection. The machine must stay on and logged in, and the integration user should not have Sage 50 open interactively at the same time, because the SDK holds the company file in a single exclusive session.

How does the integration handle ADP's mutual TLS requirement and Sage 50's lack of webhooks?

ADP requires a client certificate at the TLS layer on every call in addition to OAuth2 credentials, so ml-connector stores the certificate encrypted, presents it on each request, and tracks its expiry so a renewal is handled before it can cause an outage. Sage 50 has no webhooks or event stream, so ml-connector polls ADP general ledger documents and worker data on a schedule tied to your payroll calendar rather than waiting for a push.