Terms for a Shopify app or plugin

An app on a commerce platform's app store has three relationships to manage: with the platform, whose partner terms it has signed and whose rules on data and billing it must follow; with the merchants who install it and pay through the platform; and with the merchants' own customers, whose data flows through the app whether or not anyone thought about it. The merchant terms have to fit inside the platform's requirements, say what the app does and what it accesses, run billing and refunds the way the platform does, and deal with data in the way the platform's mandatory obligations demand. I draft those terms for a fixed fee of £995, delivered in five working days.

Who this is for

Developers and businesses in England and Wales offering apps, plugins, themes or integrations to merchants through the Shopify App Store or similar commerce platform marketplaces, on free, subscription or usage-based pricing billed through the platform.

What matters in terms for a commerce platform app

The merchant's contract and the platform's role

The terms should say that the merchant's contract for the app is with the developer, that the platform is not a party and does not support the app, that installation through the app store forms the contract on these terms, and that the platform's own terms govern the merchant's use of the platform; the developer's partner agreement with the platform requires much of this and dictates some of the wording, and the terms should be consistent with it. Merchants are businesses, so the terms are judged, where they are standard terms, under section 3 of the Unfair Contract Terms Act 1977.

Billing through the platform, trials and refunds

Charges are made through the platform's billing system, and the terms should state the pricing plans, any free trial and when it converts, that charges appear on the merchant's platform invoice, that the platform's billing cycle governs when payment is taken, and the developer's refund policy for the period after uninstall, which the platform's rules may constrain. Usage-based charges should be defined by unit and capped where the platform requires a cap, and the terms should say that the platform's records of installs and charges are the record.

Merchant data, customer data and the mandatory obligations

The app accesses the merchant's store data and the personal data of the merchant's customers, so the developer is a processor for the merchant under Article 28 of the UK GDPR and the terms must contain the processor terms, the platform requires apps to handle customer data requests and deletion requests sent through its mandatory data webhooks, and the terms should commit to doing so within the required time, describe the data the app accesses and why, list subprocessors, and address transfers under Article 46 where the app's infrastructure is outside the UK. The privacy notice for the app should match.

The licence, the app's access to the store and acceptable use

The merchant receives a licence to use the app with its store for the term of the subscription, and the terms should state the scopes the app requests and what it does with them, prohibit use of the app to breach the platform's terms or the law, prohibit reverse engineering and resale, keep the app and its code the developer's under the Copyright, Designs and Patents Act 1988, and say that the app may modify the merchant's storefront, theme or data only as its function requires and as the merchant has configured.

Support, updates and platform changes

The terms should state the support the developer provides and its hours, that the app may be updated and that some updates may be required for continued function, that the app depends on the platform's APIs and may change or cease to work if the platform changes them, and that the developer may withdraw the app from the store on notice with a refund of prepaid fees for the unexpired period. Availability commitments should exclude the platform's own outages, with the developer's obligation limited to reasonable care and skill under section 13 of the Supply of Goods and Services Act 1982.

Uninstall, data deletion and liability

The terms should say what happens on uninstall: the licence ends, the app's data about the store is deleted within a stated period unless retention is required by law, changes the app made to the storefront may persist and are the merchant's to remove, and charges stop at the next billing cycle. Liability should be capped at the fees paid in the preceding twelve months, with consequential loss and lost sales during outages excluded within the reasonableness test in section 11 of the Unfair Contract Terms Act 1977, and third-party rights excluded under the Contracts (Rights of Third Parties) Act 1999 except as the platform's partner agreement requires.

What it costs

SaaS terms of service, £995. Your standard customer-facing terms. Five working days.

Buying online forms the engagement on payment. The scope is what the saas and technology contracts page describes, you accept the Terms of Service at checkout, and I email you within four working hours to get started. If you would rather ask something first, email me.

What you get

• A bespoke contract drafted for how your product is sold, delivered and supported
• Service levels you can meet, with remedies that are proportionate rather than aspirational
• A liability position that is defensible and will survive enterprise procurement
• IP and data provisions that fit together rather than contradicting each other
• A commercial note on where you will get pushback and what is worth conceding
• One round of amendments

What is not included

• Negotiating individual enterprise deals, which I quote separately
• Advice on the law of jurisdictions outside England and Wales
• Technical security certification or audit
• Regulatory advice for regulated sectors such as financial services or health

Questions I am often asked

A merchant uninstalled our app and disputes the last charge. Who decides?

The platform's billing rules decide when a charge stops, and the terms state the refund policy for the remainder of the period. The platform's records of the install and the charge are the evidence the terms rely on.

Do we need a data processing agreement with every merchant?

The processor terms must be in the contract with each merchant, and the terms contain them, alongside the commitment to act on the platform's mandatory data webhooks. A separate signed agreement is needed only where a merchant insists on its own.

Our app changed a merchant's theme and they want it restored after uninstall. Must we?

The terms say that changes the app made may persist after uninstall and are the merchant's to remove, with guidance provided. Restoring themes is a support service the developer can offer, not an obligation the terms impose.

Related guidance and services

• SaaS and technology contracts, £995, the service this page describes
• Contract review, £495
• Data protection agreements and privacy terms, £795
• Reviewing an app store developer agreement
• Terms for a no-code product built on another platform

This page is general guidance for businesses in England and Wales, not advice on your own circumstances. Last reviewed: September 2026. Email geoffrey@caesar.co.uk.