Shopify App Development Cost 2026: Public, Custom, and Private Apps

A Shopify app quote of "$15,000" and a quote of "$120,000" can describe the same app — and one of them is hiding two-thirds of the eventual spend. Most merchants don't discover the difference until month four, when the App Store reviewer rejects v1.2 for the third time.

This post breaks down what Shopify app development actually costs in 2026 across the three engagement types — public app, custom app, private / development-store app — with realistic phase-by-phase budgets and the hidden costs that don't make it into agency proposals.

TL;DR

• Public app (App Store-listed): $45k–$220k for v1, plus $1.5k–$8k/month ongoing. The number depends almost entirely on whether your app touches checkout, payments or B2B.
• Custom app for a single merchant: $18k–$95k, no ongoing review costs but full responsibility for hosting, security and Shopify API-version churn.
• Private app via dev-store / Theme App Extension: $5k–$25k, fastest path, lowest ceiling.
• Hidden costs that wreck budgets: App-Store review iterations (3–7 cycles is typical), GDPR webhook compliance, the bulk-operation rewrite when the merchant scales past 50k orders, and Shopify's annual breaking-change cycle.

What Shopify means by "app" in 2026

Shopify's official documentation splits app types as follows. The terminology matters because it changes what you can build, how you distribute it, and how it gets reviewed.

Shopify's Help Center defines a custom app explicitly as one "built exclusively for your Shopify store," distinct from a public app "built for many stores to use."

What you're actually paying for

Every quote is some combination of the eight phases below. Where agencies vary is which phases they pad and which they hide.

Phase 1 — Discovery & spec ($3k–$12k)

Two weeks of clarifying scope, reviewing existing data, mapping merchant flows, drafting the spec. Skippable for trivial apps; non-negotiable for anything touching checkout or B2B.

Phase 2 — Architecture & API mapping ($4k–$18k)

Decisions that lock in cost for the rest of the project: GraphQL Admin vs REST? Online vs offline access mode? Theme App Extension vs storefront API? Bulk operations or paginated queries? Get this wrong and you'll rewrite Phase 4 from scratch.

Phase 3 — UI build with Polaris ($8k–$45k)

Embedded admin UI in Shopify Polaris. Polaris is mandatory for App Store apps and strongly recommended for custom — Shopify's review team rejects non-Polaris UIs in Public-app submissions roughly 60% of the time on first pass.

Phase 4 — Backend & API integration ($12k–$60k)

The actual logic. App Bridge, OAuth flow, session-token authentication, GraphQL Admin queries, webhooks, Shopify Functions (where applicable), background jobs. Pricing here scales with how many Shopify surfaces you touch.

Phase 5 — Storefront / theme integration ($4k–$25k)

If your app needs to render anything on the merchant's storefront, you need a Theme App Extension or a Storefront API integration. Theme App Extensions are the modern path — Shopify's 2025 Online Store deprecation roadmap continues to push merchants away from script-tag injection.

Phase 6 — App Store submission & review iterations ($3k–$22k for Public apps only)

The line item most agencies leave off the quote. Real-world Public app submissions average 3 to 7 review cycles before listing. Each cycle is a review by Shopify (5–14 days), agency rework (2–10 days), resubmission. Common rejection reasons:

1. UI doesn't follow Polaris guidelines.
2. Missing or non-compliant GDPR webhooks (customers/data_request, customers/redact, shop/redact).
3. Insufficient install/uninstall handling (orphan webhooks, residual data).
4. Performance regressions (storefront LCP impact > 0.5s).
5. Pricing/billing flow that doesn't use the Billing API correctly.
6. Theme App Extensions that touch DOM elements outside their declared scope.
7. Insufficient onboarding or unclear value-prop in the listing.
8. Login/session-token implementation errors.
9. Missing OAuth scope justifications.
10. Inadequate handling of the trial / free / paid plan transition.
11. App-Bridge integration warnings.

Budget the equivalent of 8–15% of total build cost for review-iteration work. Agencies that don't budget this either eat it (and burn out) or surprise-bill you for it.

Phase 7 — QA, security review, bulk-data testing ($4k–$20k)

Apps that handle order data, customer PII, or financial calculations need explicit testing of the bulk operation paths and GDPR webhooks. The merchant who installs your app on a 200k-order store on day one will surface bugs the 50-order dev store didn't.

Phase 8 — Launch, listing copy, marketing assets ($2k–$15k for Public apps)

Listing copy, screenshots, demo video, pricing-tier setup in Partners. App Store listing optimization is its own SEO discipline — listings with strong copy and 4+ screenshots convert installs at 2–3× rate of bare-minimum listings.

Total budgets by app type (v1 build only)

These are agency price points — a senior solo Shopify Partner will typically come in 30–45% lower for the same scope, with proportionally less project-management overhead.

Ongoing costs (the part most quotes ignore)

Apps don't sit still. Shopify ships breaking API changes on a quarterly cadence with a 12-month deprecation window. Every app needs a maintenance retainer or it will break.

Public vs custom — when each makes sense

Choose a Public app if:

• You're building a SaaS product, not a one-off feature for one merchant.
• You can tolerate a 3–6 month Shopify review process before earning revenue.
• You have a marketing engine that can drive App Store discovery (ASO + content + paid).
• Your unit economics survive Shopify's 15–20% revenue share.

Choose a Custom app if:

• One specific merchant (typically a Plus merchant) needs functionality no Public app provides.
• You need it live in 6–10 weeks, not 6 months.
• You don't want to pay for App Store review iteration.
• The functionality is differentiated enough to the merchant that it's worth bespoke spend, but generic enough that productising as a Public app would dilute its value.

Choose a Theme App Extension or Private app if:

• You need storefront-only behaviour (UI block, performance widget, design pattern).
• You want minimum viable install/uninstall friction.
• You're prototyping before deciding on a Public-app path.

What "Shopify Plus migration" actually costs (the related question)

If you're not building an app but are migrating to Shopify Plus, expect:

• Theme rebuild on Online Store 2.0 with Theme App Extensions: $25k–$95k
• Custom checkout extensions (Shopify Functions, post-purchase, payment customisations): $20k–$80k per surface
• B2B configuration: $15k–$60k
• Headless / Hydrogen rebuild: $80k–$350k+

For Plus migrations and Hydrogen builds we'll be writing a dedicated post — see the Hydrogen developer hiring guide (coming soon).

How to read a Shopify-app proposal in 10 minutes

Use this checklist on any quote you receive:

1. Does it line-item App Store review iterations? Should be ≥ 8% of build budget for Public apps. If absent, you'll get surprise-billed.
2. Are GDPR webhooks specified? Three named handlers (customers/data_request, customers/redact, shop/redact) with explicit data flows.
3. Does it specify Polaris React? Not "we'll use Shopify's design language" — name the package.
4. Is there a bulk-operations test plan? Required for any app that touches > 1,000 orders.
5. What's the API-version maintenance commitment post-launch? Quarterly, named, priced.
6. Who owns the Partners account? You should — never let the agency hold the dev-app credentials.
7. What's the IP / source-code agreement? Must specify code escrow or transfer on completion.
8. Are billing-API edge cases scoped? Trial-to-paid, plan changes, refunds, webhooks for installs/uninstalls.

FAQ

Can a junior developer build my Shopify app cheaper? For trivial Theme App Extensions, yes. For anything touching billing, checkout, B2B, or bulk operations, no — every senior Shopify dev I know has fixed at least one app where a junior used REST where Shopify expected GraphQL Admin, didn't implement bulk operations, and got the merchant to a 100k-order limit before the app fell over.

How long does App Store review take in 2026? First-pass review: 5–14 business days. Each subsequent submission: 5–10 business days. Plan for 6–10 weeks total from feature-complete to listed for non-trivial apps.

Do Shopify Plus merchants pay differently? Plus merchants typically engage on custom apps rather than Public apps for proprietary functionality. They also tend to pay 20–40% above SMB pricing for the same scope because the engagement carries Plus-grade SLA, security review and account-management overhead.

What about AI / agent apps for Shopify? 2026 has seen a surge of AI-driven Shopify apps (recommendation, support, content generation). Budget the same as Heavy-Public-app numbers above plus model inference costs — typically $0.5k–$5k/mo at 1k merchants installed, scaling roughly linearly.

Are there cheaper offshore Shopify dev shops? Yes — credible offshore Shopify partners in India, Pakistan and the Philippines can deliver Light/Medium Public apps at 35–55% below the US/UK ranges above. The trade-off is App Store review responsiveness — most offshore shops batch review-cycle work, lengthening end-to-end time-to-listing by 3–5 weeks.

Need a Shopify app built or audited? First Bridge Consulting designs and ships Public, Custom and Theme App Extensions for Shopify Plus and SMB merchants. Get a build quote in 48 hours →

Sources

• Shopify About Apps — Help Center
• Shopify Custom Apps Guide — shopify.dev
• Shopify Custom App Development — Charle Agency
• Shopify App Development Service — Amasty
• Shopify App Development Company — Dinarys