Shopify Sage Intacct Integration: REST API, OAuth, and Financial Posting

Sage Intacct is a cloud financial management system popular with US mid-market companies, including many direct-to-consumer brands that outgrew QuickBooks. Unlike ERPs that run the warehouse, Intacct usually sits at the end of the chain: Shopify (or an order management system and a 3PL) handles orders and fulfillment, and Intacct needs accurate revenue, receivables, cash, fees, and tax. The integration design is therefore mostly a posting design. As on every page, documented marks statements from Sage or Shopify documentation, and recommendation marks our guidance. Nothing here is accounting or tax advice.

REST, XML, and authentication

Documented: Sage Intacct recommends the REST API for client applications. The XML API continues to be supported and existing integrations keep working, but all new objects and features are released using the REST API.

Documented: the REST API uses OAuth 2.0. Sage documents the authorization code grant, the client credentials grant, and PKCE for public clients. A web services sender ID must be authorized by the company — added on the Company Security settings or approved by an admin during OAuth authorization.

Recommendation: build new integrations on REST. Use a dedicated integration user with only the permissions the postings need, store refresh tokens securely, and alert when authorization is revoked. If you inherit an XML-based connector, it will keep working, but new Intacct capabilities will arrive on REST.

Decide the posting design first

Approach	What Intacct receives	Fits
Daily or per-payout summary	Summarized sales, discounts, shipping, tax, refunds, and fees per day or payout, with dimensions	High-volume D2C; Shopify keeps order detail
Per-order AR	An invoice (or sales document) per order, with payments applied	B2B orders on terms; low volume
Hybrid	Summaries for card-paid D2C, per-order invoices for wholesale	Blended D2C and B2B stores

Recommendation: agree the design with your controller and Intacct partner before choosing a connector or writing code. Decide:

• Dimensions every posting carries (channel, store, location, department, class).
• Accounts for sales, discounts, shipping income, tax liability by jurisdiction, merchant fees, refunds, and the Shopify clearing account.
• Timing: post by order date, ship date, or payout date — this decides which period revenue lands in.

Payout reconciliation

Documented (Shopify): Shopify Payments balance transactions record each charge, refund, adjustment, and payout with gross amount, fee, and net, and are associated with the payout that settled them.

Recommendation: post payments into a clearing (undeposited funds) account, then post each payout as a deposit that clears them and books fees, refunds, and chargebacks to their own accounts. The clearing account should return to near zero after each payout. See reconciling Shopify payouts.

Sales tax

Recommendation: post the sales tax Shopify or your tax engine calculated at checkout, by jurisdiction, rather than recalculating it in Intacct. Keep marketplace-collected tax out of your own liability. See sales tax in ERP integrations.

Refunds and adjustments

Recommendation: refunds reverse sales, tax, and shipping in the same dimensions and accounts as the original posting. In a summary design, refunds get their own lines in the day’s (or payout’s) summary rather than being netted against sales. Chargebacks and dispute fees are booked when they appear in the payout data.

Idempotency and audit

Recommendation: every posting carries a deterministic reference — the payout ID for payout postings, the date and store for daily summaries, the Shopify order ID for per-order documents — and the integration checks for an existing posting with that reference before creating one. Keep the source data behind each summary so auditors can trace any line back to orders and payout transactions.

Common pitfalls

• Posting every order when finance only needed summaries, creating noise and API load.
• Missing dimensions that make channel or location reporting impossible later.
• Fees never booked, so revenue and cash are overstated.
• Tax recalculated in Intacct, creating differences from what customers paid.
• Reposted summaries after a retry because postings had no deterministic reference.