TL;DR: A custom Shopify app costs $500 to $45,000 in 2026, and the architecture sets the price, not the feature list. An extension-only app runs about 10 to 40 hours, a server-backed app 60 to 150, and a two-way ERP or 3PL sync 120 to 300. Plus is required for custom apps with Functions. Check Flow and existing connectors before you build anything.
I asked ChatGPT what a $3M Shopify store should budget for a custom app that syncs orders to a 3PL and adds checkout discount logic. It said $16,000 to $35,000 with a senior freelancer and $30,000 to $65,000 with an agency.
That can be right. It can also be four times too high. The three custom Shopify apps I shipped for one regulated Plus client ran no backend server at all.
The difference is one question nobody on page one of Google asks first: does this app need a server?
Why this matters for your store
- An app that needs no server has $0 hosting and no database to secure, so its lifetime cost is mostly the build.
- A custom app with Shopify Functions works only on Shopify Plus, so a non-Plus store can pay for a build it cannot install.
- Shopify ships a new API version every 3 months, so a custom app is a small recurring cost, not a one-time purchase.
How much does a custom Shopify app cost in 2026?
The top-ranking guides quote ranges by hiring model. One 2026 guide puts a simple freelance custom app at $2,000 to $5,000 and a complex agency build at $30,000 to $75,000+. Those ranges are wide because they mix four different kinds of app. Split by architecture, they tighten up:
| App type | What it does | Hours (my estimate) | At $50/h | At $150/h |
|---|---|---|---|---|
| Extension-only | Checkout UI, a Function, or an admin block. No server | 10 to 40 | $500 to $2,000 | $1,500 to $6,000 |
| Server-backed | Webhooks, an admin page, its own data | 60 to 150 | $3,000 to $7,500 | $9,000 to $22,500 |
| Two-way integration | Orders out, tracking and stock back, retries | 120 to 300 | $6,000 to $15,000 | $18,000 to $45,000 |
| Public App Store app | Multi-merchant billing, review, support | 300+ | $15,000+ | $45,000+ |
The hours are my scoping estimates for a store in the $1M to $10M band, not a quote. I bill $50 an hour; senior North American freelancers sit around $48 to $74, and Plus agencies around $100 to $250, which I break down in what a Shopify expert costs.
The last row is there for contrast. If you are a merchant, you almost never need a public app. A custom app installs on one store, or on several stores in the same Plus organization, per Shopify’s app distribution docs.
Does my custom Shopify app need a server?
This is the 30% question, and it moves the price more than anything else.
An extension-only app lives inside Shopify. A Checkout UI extension renders a field or a panel in checkout. A Shopify Function runs your discount, shipping or validation logic on Shopify’s own infrastructure. An admin UI extension adds a block to the order or customer page. None of them needs hosting, OAuth screens or a database.
You need a server when the app must remember something Shopify cannot store, call a system outside Shopify on a schedule, or receive webhooks. An order sync to a 3PL is the classic case.
Here is what that looked like on a real build. For an anonymized UK aesthetics and pharmacy group on Plus, I shipped three custom apps across five extensions: checkout consent panels, an age-and-eligibility gate, a server-side gating Function and an admin extension. The consent app’s config reads scopes = "" and network_access = false. No hosting bill, no API scopes, nothing to patch on a server.
The one job that needed real backend logic, practitioner registration with document uploads, went on a single stateless Cloudflare Worker that stores nothing and keeps Shopify metafields as the record. Cloudflare’s Workers pricing gives 100,000 requests a day free and the paid plan starts at $5 a month.
So before you price anything, ask the developer to sort every feature into “runs inside Shopify” or “needs a server.” Most quotes get cheaper on that pass alone.
Do custom Shopify apps need Shopify Plus?
Some do, and this catches non-Plus stores out. Shopify’s Functions documentation is explicit: “Only stores on a Shopify Plus plan can use custom apps that contain Shopify Function APIs.” Public App Store apps with functions work on any plan.
Checkout has a similar line. Shopify states that Checkout UI extensions for the information, shipping and payment steps are Plus-only. The Thank you and Order status pages are open to every plan.
What that means in money: a Basic or Grow store that wants custom tiered discounts should not commission a custom Function. It should buy a public discount app, or move the logic into an automatic discount it can configure. I wrote up the Plus route in my tiered bundle discount Function walkthrough.
What are the line-item hours on an ERP or 3PL sync app?
This is the expensive one, so here is how a fair quote should break down for the $3M store in the ChatGPT question: orders out to a 3PL, tracking and stock back, plus custom discount logic.
| Line item | Low | High |
|---|---|---|
| Discovery and field mapping (SKUs, addresses, discounts, taxes) | 10 h | 20 h |
| App scaffold, auth, deploy pipeline | 4 h | 8 h |
| Order webhooks with duplicate and ordering protection | 15 h | 30 h |
| Reconciliation job that re-fetches what webhooks missed | 10 h | 20 h |
| Tracking, stock and cancellation sync back to Shopify | 15 h | 35 h |
| Admin page with sync log and a retry button | 10 h | 25 h |
| Discount logic as a Function (Plus only) | 10 h | 25 h |
| Testing against the 3PL sandbox, edge cases, docs | 20 h | 40 h |
| Total | 94 h | 203 h |
| At $50 an hour | $4,700 | $10,150 |
| At $150 an hour | $14,100 | $30,450 |
Two rows decide whether this app survives its first holiday season.
The webhook row is first. Shopify’s webhook documentation says it “doesn’t guarantee ordering” and tells you to ignore duplicates by X-Shopify-Webhook-Id. An app built without that protection ships an order twice.
The reconciliation row is second. The same page says “your app shouldn’t rely on receiving data from Shopify webhooks” and recommends periodic reconciliation jobs. A quote with no reconciliation line is a quote for an app that will quietly drop orders.
Should I build the integration at all?
Often, no. I check three cheaper paths before scoping a sync app.
- Shopify Flow. Shopify says Flow is a free app on the Basic, Grow, Advanced and Plus plans. Tagging, routing and alert workflows cost nothing to run.
- The vendor’s connector. Most 3PLs and ERPs sell a Shopify connector already. Even a $200 a month connector beats a 150-hour build on cash for years.
- A middleware layer. On Factory Direct Blinds, orders already flowed to the supplier through LogicBroker EDI. I did not build an integration. I made the new product builder write cart data in the shape the EDI feed expected, which cost hours, not weeks.
Build custom only when the workflow is the business: a pricing rule, a gate, or a fulfillment step no off-the-shelf tool models. My comparison of Shopify apps vs custom development covers the storefront side of the same decision.
What does a custom Shopify app cost to maintain?
More than zero, which is the line most quotes leave out. Shopify’s API versioning page says a new version ships every three months and each one is supported for “a minimum of 12 months.” When yours expires, Shopify falls forward to the oldest supported version, which can change the data your app receives.
My working budget:
- Extension-only app: 1 to 2 hours a quarter for version bumps and a test deploy. Hosting $0.
- Server-backed app: 2 to 6 hours a quarter, plus $5 to $50 a month in hosting and monitoring.
- ERP or 3PL sync: the same hours, plus an on-call plan. Someone has to answer when orders stop flowing on a Saturday.
That last line is the real freelancer-or-agency question. A solo developer builds the integration well. An agency, or a freelancer with a named backup, covers the outage when the solo developer is asleep. I go deeper on that trade in CRO agency vs freelancer, and the same logic holds for app work.
Get the custom Shopify app scoping sheet
The one-page PDF has the architecture test, the cost tiers at $50 and $150 an hour, the sync-app line items, the Plus gates, and the questions to ask before you sign. Hand it to any developer you are interviewing.
Download the custom Shopify app scoping sheet (PDF)
How do I check a custom app quote in 5 minutes?
- Ask which features run inside Shopify and which need a server. If the developer cannot answer, they have not scoped it.
- Search the proposal for “reconciliation,” “duplicate” and “API version.” A sync app quote missing all three is underpriced now and expensive later.
- Confirm your plan. If the scope includes a Function or a checkout-step extension and you are not on Plus, stop and rescope.
For the wider vetting list, use my 12 questions to ask before hiring a Shopify developer. I bill $50 an hour and publish my engagement terms. If you have a custom app quote on the table, book a free 30-minute call and I will tell you which parts need a server and which do not.
The takeaway
- Sort every feature into “runs inside Shopify” or “needs a server” before you price it.
- Check Flow, the vendor’s connector and middleware before commissioning a sync app.
- Confirm Plus before you pay for a custom Function or a checkout-step extension.
- Require webhook duplicate protection and a reconciliation job in any sync quote.
- Budget quarterly API upkeep and an on-call plan, not just the build.
Kaspian Fuad is a Shopify developer and CRO specialist with 12 years and 100+ stores behind him. He publishes his rates and engagement terms on kaspianfuad.com.