Issue invoices from Synthelio and pull transactions back to complete the P&L picture.
The QuickBooks Online connection does two jobs that run in opposite directions. Synthelio creates invoices in QuickBooks from your engagement data, and QuickBooks sends cost and income transactions back into Synthelio, where they can be matched to engagements.
Together those two flows close a loop most firms in this category never close. Engagement margin tells you whether a piece of client work is performing. Accounting tells you whether the business made money. Without a connection between them, the two numbers live in separate systems, disagree with each other, and nobody can explain why.
The accounting connection belongs to a legal entity rather than to your workspace as a whole. Each entity gets its own QuickBooks connection, its own invoice numbering, its own payment terms, and its own payment instructions. One entity is marked as the default.
This matters for any firm running more than one company, which is common once you have a Polish operating entity and a US one, or a holding structure with separate books. Invoices issued by each entity need to carry that entity's bank details and follow that entity's numbering sequence, because they are separate sets of books that get audited separately.
If you only have one entity, this is invisible. You configure the default and never think about it again.
Authorize the connection through Intuit from the entity's settings panel, then turn on the QuickBooks Online toggle. The panel shows the connection status and when the last sync ran, and Reconnect QuickBooks re-authorizes when the connection expires.
It will expire eventually. Intuit tokens have a finite life and a reconnect is routine maintenance rather than a sign that something broke. If transactions stop appearing, check the connection status before assuming there were no transactions.
There is also a sandbox mode toggle, which points the connection at a QuickBooks sandbox company instead of your real books. Use it while you are testing invoice numbering and payment terms. Turn it off before you issue anything real, and confirm it is off, because an invoice generated against a sandbox is not an invoice.
Synthelio generates invoices through the QuickBooks API rather than making you rekey them. Three settings control what comes out.
Invoice numbering. Choose a format built from tokens: YYYY, YY, MM, DD, and # for the sequence, where ## produces 01, 02, and so on. A format of YYYYMM-## yields numbers like 202608-01. The next number is read from the invoices already in QuickBooks, not from a counter Synthelio keeps, so the sequence continues from your real books rather than starting a parallel one.
That last detail is worth understanding before you change anything. Numbering is often a legal requirement rather than a preference, particularly for VAT-registered entities in the EU, where sequences are expected to be unbroken and chronological. If you switch formats mid-year, you are changing something an auditor will look at.
Default payment method and terms. Payment methods and terms are pulled from QuickBooks rather than defined in Synthelio, and Refresh from QuickBooks re-reads them after you add a new one there. The default is pre-selected whenever an invoice is generated for that entity.
Payment instructions. Free text printed on every invoice from that entity, typically bank details, and editable per invoice when a specific client needs something different.
In the other direction, QuickBooks sends cost and income transactions into Synthelio. Sync now pulls recent activity and reports how many transactions came through on the last run. Backfill pulls history, which is what you want when you first connect or after a gap.
A run reporting zero transactions is normal on a quiet day and worth investigating if it repeats. Check the connection first.
This is the part that produces the end-to-end view, and it is the part that takes actual effort.
A synced transaction starts unattached. Matching it to an engagement is what turns a general ledger entry into engagement-level cost or revenue. Once matched, a subcontractor invoice, a travel expense, or a piece of licensed software stops being a firm-wide overhead line and becomes a cost attributable to the specific piece of client work that caused it.
The engagements where this changes the picture most are the ones with real pass-through cost. An engagement staffed entirely by your own employees is well described by hours multiplied by cost rates. An engagement with two subcontractors, a travel budget, and a third-party license is not, and its margin will read several points too high until those transactions are attached to it.
Unmatched transactions are not lost. They sit at the firm level, which is correct for genuine overhead like rent and tooling. The discipline is reviewing the unmatched list regularly rather than letting engagement-specific costs quietly accumulate as company overhead, because that is precisely the error that makes every engagement look profitable while the business does not.
Even with the connection running, engagement margin in Synthelio and profit in QuickBooks will not agree, and they are not supposed to.
Synthelio reflects hours as they are logged. QuickBooks reflects revenue as invoiced and cost as paid. Engagement margin covers one piece of client work and excludes firm overhead. Accounting covers the whole business including everything that never touches an engagement.
The connection is not there to make the two match. It is there so you can move between them and account for the gap, instead of having two numbers with no relationship to each other.
Does Synthelio change my existing QuickBooks data? It creates invoices. It reads transactions, payment methods, and terms. It does not rewrite your books.
Can I keep issuing some invoices manually in QuickBooks? Yes, and the numbering will stay consistent, because the next number is read from QuickBooks rather than from a separate Synthelio counter.
What happens if the connection expires mid-month? Invoice generation for that entity stops until you reconnect, and transactions accumulate on the QuickBooks side. Reconnect and run a backfill to catch up.
Do I have to match every transaction? No. Match the ones attributable to a specific engagement. Genuine overhead belongs at the firm level and should stay there.
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