Start with the ERP, not the agency
The ERP decides the architecture more than Magento does. Write down the product, the edition, and the release: Epicor Prophet 21, not Epicor; Dynamics 365 Business Central, not Dynamics; SAP S/4HANA, not SAP. Then write down the interface that edition exposes and what governs it. Oracle's NetSuite documentation, for example, governs concurrency at the account level and sets the limit by service tier plus 10 per SuiteCloud Plus license; Bemeir's Business Central article notes a cap of 200 webhook subscriptions per environment. Those two numbers alone rule out some sync designs before any agency is called.
Write the ownership split before the RFP
Every object needs one writer and one cadence. The split Bemeir publishes in its Adobe Commerce B2B article is a workable default: the ERP is the system of record for pricing, on-hand inventory, credit limits and holds, and order and invoice status once an order is placed; Commerce owns the storefront, the cart, requisition lists, quotes in progress, and purchase-order approvals. scandiweb's BK-Group case shows the same split running, with per-customer prices pushed to Pimcore every few minutes and stock read from the ERP by direct API call. Put your version of that table in the RFP. An agency that proposes to change it should say why; an agency that ignores it has not read it.
Match the agency to the object set
Agencies on this site publish different object sets. Creatuity's P21 page names products and customer-specific pricing, inventory, orders, customer data, and shipment tracking. Wagento's ERP page goes wider, to credit terms, purchase orders, warehouse allocations, and financial postings. iWeb's Prophet 21 page lists pricing and discounts, stock, account ordering, orders and invoices, fulfilment and returns, and customers. List your objects, diff them against the agency's published list, and ask about every gap. The gap is the custom build, and the custom build is where the estimate moves.
Read the case, then ask what it did not measure
- Does the case name the client, the ERP product, and a number after go-live? scandiweb's Macron, Wagento's LAPP Tannehill, and iWeb's Donaldson Group do; most pages on this site do not
- Does the number belong to the integration or to the whole program? Donaldson's figures cover a replatform, a PIM, and the connector; ask which moved which
- Who else is credited? Wagento's case credits a third-party integration platform plus custom API calls; that is two vendors on call
- Is the ERP the same edition as yours? A Prelude case is not a Prophet 21 case
- Is the case on the same platform? Human Element's Karmak case is on BigCommerce
Five questions for the sales call
- Which ERP edition and release is in scope, and which interface will you use, with what authentication
- What is the concurrency or rate limit on our account, and who will measure it before the design is fixed
- Where do failed messages go, who watches that queue, and what happens during our month-end close
- Will integration code run in app/code or out of process, and what changes if we move to Adobe Commerce as a Cloud Service
- Which of our B2B features (company accounts, shared catalog, negotiable quotes, PO approval) map to which ERP object, and which need the Adobe Commerce B2B package
Adobe's feature comparison states that the SaaS edition runs out-of-process extensions only, and its lifecycle page has 2.4.6 out of regular support since 11 August 2026, so questions four and five are not hypothetical for a store on an older release. Vague answers to questions two and three predict most post-launch order loss.
Check the support desk before go-live, not after
Integration bugs surface in the first month-end close after launch. Read the agency's support page as carefully as its case studies. IronPlane's support page names ongoing updates and security monitoring and states no response time; scandiweb's support page states a first-response commitment and a pay-as-you-go model, both as its own statements. Ask every agency the same question: who answers at 07:00 on the first working day of the month when the ERP posts a full price file and the storefront indexer has not finished.
Where scandiweb fits, and where it does not
scandiweb publishes this site and ranks first on it, so read this paragraph with that in mind. Its published fit is the program with several systems in scope: the Macron case with SAP, Pimcore, and over 150 countries, or the IONTO case with an upgrade and an Infor connector overhaul under one contract. It publishes no Prophet 21 connector, no NetSuite case, and no App Builder integration, and its Clutch minimum is $25,000. For a P21 distributor, Creatuity or Human Element; for a UK team, iWeb; for the design document first, Bemeir; for a B2B ordering layer on a working connector, IronPlane. The scenario table on the ranking page pairs fifteen situations with a pick and an alternative.