Sage 50 and TaxJar integration

What moves between them

Sales transactions flow from Sage 50 into TaxJar. After each poll cycle, ml-connector extracts completed sales invoices from Sage 50 - including invoice number, date, customer address, line items, and amounts - transforms the detail into TaxJar's order schema, and submits each order to TaxJar's /transactions/orders endpoint so TaxJar can calculate the tax liability and track the transaction for state return filing. Refunds are posted separately to /transactions/refunds. No data flows back from TaxJar into Sage 50; TaxJar is read-only for calculation and compliance reporting.

How ml-connector handles it

ml-connector runs a Windows process with SDK access to Sage 50, authenticating with the local username and password you provide and the company path (filesystem location of the data files). It polls Sage 50 on a schedule you set - typically hourly or daily depending on transaction volume - and queries sales invoices by LastModifiedDate or TransactionDate to find only new and updated records since the last sync. For each invoice, ml-connector extracts the customer billing address, line items with product categories and amounts, and shipping address if present. Before posting to TaxJar, it validates the customer address using TaxJar's address validation endpoint to catch typos that would distort tax calculations. It then submits the order to TaxJar with the validated address, and if TaxJar returns a 422 conflict (duplicate transaction), ml-connector uses PUT to update the existing record instead. The API key is stored encrypted at rest and used on every request with automatic retry on transient failures. Every transaction record, validation result, and API response is logged to the audit trail.

A real-world example

A mid-sized e-commerce retailer runs Sage 50 for accounting and inventory across three warehouses, and uses TaxJar to calculate and file sales tax in the 45 states where they have nexus. Before the integration, the accounting team exported sales invoices from Sage 50 weekly and manually uploaded them to TaxJar, a process that took several hours and often contained address typos that inflated or deflated tax calculations. With the integration running, every sales invoice syncs from Sage 50 to TaxJar automatically within hours of being marked complete, addresses are validated before submission, and tax rates are calculated in real-time. The team now spends zero time on manual data entry, and their monthly tax liability is accurate and auditable back to the original invoice.

What you can do

• •Poll sales invoices from Sage 50 and submit them to TaxJar for tax calculation and state return reporting.
• •Validate customer addresses against TaxJar's address database before posting, reducing tax calculation errors from bad data.
• •Handle both new invoice submissions and updates to existing transactions using TaxJar's idempotency pattern.
• •Encrypt the API key at rest and manage the Sage 50 SDK session lifecycle across poll cycles.
• •Log every transaction, validation result, and API call so you can audit the sync and replay failed submissions.

Questions

Why does the integration need a Windows machine with Sage 50 installed?

Sage 50 is a desktop application with no cloud API. The local SDK is the only way to access company data files, and it only works on Windows with direct filesystem access. ml-connector runs a service on that machine to poll the data and send it to TaxJar's cloud API.

Does ml-connector send transaction data back to Sage 50 after TaxJar calculates tax?

No. TaxJar is read-only in this integration. ml-connector sends sales invoice detail from Sage 50 to TaxJar so TaxJar can calculate the tax liability and report it to state authorities. Tax amounts calculated by TaxJar do not flow back into Sage 50 - you manually record tax payable in Sage 50 based on TaxJar's reports.

What if an address in Sage 50 is incomplete or formatted incorrectly?

ml-connector validates every customer address against TaxJar's address database before submission. If validation fails, the transaction is logged as a validation error, and you can edit the address in Sage 50 and re-run the sync. This prevents malformed addresses from reaching TaxJar and distorting tax calculations.