ERP integration is the work most likely to blow a project budget, and almost always for the same reason: the scope was written against what the systems should do rather than what they currently contain.
The ranges
| Middleware connectorCeligo, Patchworks or similar, configured properly | $4,000 - $15,000 |
| Custom integrationDirect, built to your processes and data model | $20,000 - $60,000 |
| Complex, multi-entitySeveral warehouses, entities or currencies, real-time requirements | $60,000 - $150,000+ |
Middleware also carries its own monthly licence, typically several hundred to a few thousand.
What drives the number
Which ERP. A modern cloud ERP with a decent REST API is a different project from an on-premise system whose integration surface is a nightly file drop.
How many objects sync, and which direction. Products, inventory, prices, orders, customers, returns, fulfilments. Each is a workstream, and bidirectional is more than twice one-way because now you have conflicts to resolve.
Real-time or batch. Hourly batch is straightforward. Real-time inventory across several locations is a different class of problem.
Your data. This is the one that surprises people. If SKUs do not match between systems, if the ERP holds products Shopify does not, if units of measure differ — that reconciliation is the project, and it happens before any code runs.
Ask any integrator to review a real export from both systems before quoting. A quote produced without seeing your data is a guess, and the variance on that guess is larger than the quote.
Middleware or custom
Start with middleware. Celigo, Patchworks and their peers solve the common patterns well, they are maintained for you when APIs change, and they are considerably cheaper to start.
Build custom when your process genuinely does not fit the patterns, or when the middleware licence at your volume exceeds what a maintained custom integration would cost.
Talk it through
Tell us which ERP and what has to sync.
We will tell you whether middleware covers it, what a custom build would take, and where the data problems are likely to be hiding.
Get it scopedA real read within one business day — not a sales call.
The ongoing cost
Integrations are not build-and-forget. APIs version, ERPs get upgraded, and business rules change. Budget for maintenance from the start — an unmaintained integration fails silently, and the first symptom is usually an overselling incident.
About the author
Manpreet Singh
Manpreet Singh is the founder of Proscube, an ecommerce growth studio. He leads the studio's Shopify and Shopify Plus engineering, headless builds, CRO, and its work on AI engine optimization, and writes its guidance on how to grow a DTC brand without wasting money. He works directly with founders — no account-manager layers between you and the people doing the work — and would rather tell a client not to build something than sell them work they don't need.
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