Compare build and buy for finance data integration on one recurring output, and count the work each option leaves with your team after launch. Connector lists, platform diagrams and licence costs leave the Controller’s question open: who maintains the explanation behind a supplier balance once the project ends?
Specify the records, interpretation, evidence and review that output requires. Then ask an internal team, an implementation partner and a software provider to show the same piece of work. You get a comparison of complete responsibilities, and you see when the existing stack needs only a modest extension.
Define the output you are comparing
“Integrate AP data” leaves too many questions open. A tighter scope reads: prepare a supplier-credit review packet for one entity, showing the original credit, prior applications, unresolved amount and supporting records through a defined cutoff.
Specify the supplier population and exclusions. Name the intended reviewer and the sources they need to inspect. State whether the service includes investigating ambiguous allocations or only importing the records.
Use a known difficult case. In this series’ illustrative example, CN-410 is a $20,000 credit with $14,000 applied earlier, and the possible $6,000 remainder still needs checks. An option that imports only the original credit supplies a different output from one that keeps the reviewed application history.
Map what your existing systems already do
Locate the maintained supplier mapping, source history, measure definition and review evidence. Ask who owns each one and which workflows use it.
The ERP might already hold the approved account structure, a warehouse the transaction relationships and a document store the supporting agreement. The missing piece is often the connection between them, an investigation step or reliable reviewer access. The finance data warehouse, canonical model and semantic layer comparison helps you place each one.
Record that gap before you assign it to a new product. An internal build makes sense when your team has the capability and the maintenance capacity. Outside support makes sense when it supplies a defined responsibility your team cannot sustain today. Both conclusions need evidence from the same scope.
Build vs buy: compare the work after launch
Initial connection and ongoing operation are different jobs. Ask each option to explain what happens when an export changes, a new supplier reference appears or a reviewer cannot open a supporting document.
| Responsibility | Question for every option |
|---|---|
| Source coverage | Who identifies a missing period and repairs the import? |
| Mapping | Who resolves an ambiguous supplier or entity relationship? |
| Interpretation | Who reviews the calculation and accounting meaning? |
| Evidence access | Who makes the support usable by the intended reviewer? |
| Change handling | Which outputs are revisited when a source or definition changes? |
| Continuity | Who maintains the workflow when the original implementer is unavailable? |
Keep the customer-owned work in each comparison. If an option quotes a lower fee because your finance team still investigates allocations or maintains the mappings, write that effort and ownership into the comparison. The arrangement can still be the right one.
Separate cash expenditure from internal effort
Use one comparison period and the same deliverable. Record external setup charges, recurring charges, expected support and any exceptional work the proposal excludes.
Record internal setup, review, correction and maintenance hours on their own lines. If finance assigns a rate to those hours, label the result an internal resource valuation and keep it apart from cash expenditure and savings.
For a simple comparison, external cost equals setup charges plus recurring charges over the period, with other scoped costs on their own lines. Internal resource value equals estimated hours multiplied by the chosen rate. Show the assumptions beside each figure and skip the single return number.
An hour released from integration work leaves the payroll unchanged, because your team spends it on other work. A cash-saving claim needs its own basis, such as an actual change in spend.
Ask a second workflow to use the result
After the AP packet is complete, hand its explanation to a close reviewer. Ask them to reproduce the prior application through their own authorised access.
This tests whether the investment leaves reusable work behind. If someone has to remap the supplier, find the same document or rebuild the application calculation, record that dependency in the comparison. If the source history itself has gaps, reconciling the ERP data backfill comes first.
Ask for a usable export of the mapping, definition and supporting references in scope, and confirm the actual interface or file. A diagram does not prove portability or compatibility with another reporting tool.
Make a bounded decision
Record the chosen output, demonstrated results, unresolved dependencies, continuing customer responsibilities and the next review date.
You might extend the existing system, build a maintained workflow, engage outside support or narrow the scope. Pick the arrangement whose work and ownership your finance team can explain.
If you want a reading on your own records before you decide, the Explore Rever page on the zero-day scan describes Rever’s first pass over your connected records once read-only access is in place, with initial findings and the evidence behind them. Missing sources stay visible in the results, and the free Proof of Value runs the scan on a limited period of your data.
Start with the One Balance, Two Workflows worksheet. Run the handoff test before you compare proposals, then hold every option to the same case and evidence requirements.
To run that handoff test on screen, Can the Explanation Travel? checks the identity, meaning, time and evidence that travel between two workflows and prints a handoff summary with the gaps and their owners.
