Integrate iPaaS.com with QuickBooks Online to post sales receipts, invoices and payments to QuickBooks, and to keep customers, items, inventory quantities, invoice status and payment methods in sync. This article is the reference for connecting a subscription and for every setting; the QuickBooks Online Installation Instructions walk through first-time setup.

You do not create an Intuit developer app or copy any keys. The integration signs in through iPaaS.com's own Intuit app, whose keys iPaaS.com keeps on the integration.

The settings below need more than a line.

Leave it at quickbooks.api.intuit.com. The sandbox host (sandbox-quickbooks.api.intuit.com) is for iPaaS.com's own testing. https:// or http:// in front, a trailing slash, and anything after the host are removed, so https://quickbooks.api.intuit.com/ works. A host the integration cannot reach fails with QBOL-EXTN-1002.

Leave it at 75. A blank value uses 75, and QuickBooks answers a minor version below 75 as 75 (Intuit: Minor versions of our API, checked October 2026), so a lower value has no effect.

After the first poll, each poll starts from the newest change the previous poll saw, and this setting no longer applies. A blank, zero, negative or non-numeric value uses 7. To bring in older history on a new subscription, raise it before the polls first run.

A value above 1000, QuickBooks' maximum per page (Intuit: Query operations and syntax, checked October 2026), is treated as 1000. A blank, zero or non-numeric value uses 100. Leave them at the default unless your MiSP or iPaaS.com Support suggests otherwise.

It applies to items created by the Product collection and to items created for transaction lines; a missing shipping item is always created as a Service item. Any value other than Service is treated as NonInventory. An Inventory item is created only when the mapping sets Type to Inventory.

Lines are matched to items by the Item Id the line maps, else by SKU, else by name.

Only the value false turns this off.

A name or id. A blank value leaves the account to QuickBooks. An account QuickBooks doesn't have fails with QBOL-NFND-1009.

When the company's shipping field is on for sales forms, the shipping amount goes in that field and this setting is not used. When it is off, the shipping amount becomes a line for the item with this name; if QuickBooks has no item by that name, it is created as described under Create Missing Items. A blank value uses Shipping.

QuickBooks keeps one quantity per item and has no locations, so every quantity TO iPaaS.com carries this value as its Location Id. Use the id of one of your iPaaS.com locations, and map it to the inventory's location in the Product Inventory collection. Left blank, quantities TO iPaaS.com fail with NFND-1003 - Location Id: 0 does not exist or can not be found. A subscription copied from another iPaaS.com company keeps that company's location id: change it to one of your own locations.

The integration signs in with OAuth 2.0 through iPaaS.com's own Intuit app. To authorize a subscription:

After that, the integration keeps itself signed in. The access token lasts an hour and is renewed automatically with the saved refresh token. A refresh token stays valid for 100 days (Intuit: Authorization FAQ, checked October 2026); every renewal saves a new one, so a subscription that keeps transferring stays signed in. Authorize again only after the app is disconnected in QuickBooks, or after 100 days without a transfer.

Errors when you click Authenticate:

When transfers fail with "Unable to connect to subscription": a sign-in or company problem stops the transfer before any data moves, and the transfer error reads only "Unable to process transfer. Reason: Unable to connect to subscription with id ...". The coded reason is in Activity Tracker, in the entries at the same time as the error, with the same reference id. QBOL-AUTH-1002 and QBOL-AUTH-1003 can also appear in the transfer error itself, when QuickBooks refuses the sign-in partway through a transfer.

Disconnecting the app in QuickBooks does not stop transfers at once: they keep working until the current access token lapses, up to an hour. Do not edit the Access Token or Refresh Token values the integration saves in the subscription's Persistent Data; if they are removed, transfers fail with QBOL-AUTH-1002 until you authorize again. Every code is in QuickBooks Online Error Messages.

Currently, initialization is not supported for QuickBooks Online in iPaaS.com. The first poll of each kind of record brings in the changes of the last Initial Poll Days, and records FROM iPaaS.com are sent as they are created or updated. To restart a poll, delete its Last Date of ... Poll value in the subscription's Persistent Data: the next poll starts again from Initial Poll Days. For a large set of existing records, see bulk sync using Postman.

Throttling keeps the integration within QuickBooks' API limits during heavy transfers. The throttle fields on the subscription (API Throttle Limit, API Throttle Seconds and their TO iPaaS counterparts, Concurrent Connections and Concurrent Batch Executions) are required, but their values are pre-populated and do not normally need to be changed: 500 requests per 60 seconds both ways, 10 concurrent connections and 10 concurrent batch executions. For details, see Subscription Configuration – Edit.

QuickBooks allows 500 requests a minute for each QuickBooks company and 10 requests a second for each company and app (Intuit: API call limits and throttles, checked October 2026). A refused request fails the transfer with QBOL-EXTN-1014, and iPaaS.com retries it after a minute. QuickBooks also applies an overall monthly allowance for data reads that iPaaS.com manages for its Intuit app; each poll uses part of it, even when it finds nothing, so set the polls to run every 15 minutes, not more often (see QuickBooks Online Known Limitations). If rate-limit errors continue for hours, contact your MiSP or iPaaS.com Support at support@ipaas.com.