SMF·SELLFY
Can a prompt replace Sellfy?
Online stores & courses — digital products, courses and memberships
Exhibit tracking slip
Verdict
Sellfy's distinguishing feature against a plain download store is the subscription: buyers pay monthly for access to a library that keeps growing. Stripe Billing handles the money, but the part you have to build correctly is entitlement over time — what a member can reach today, what happens the month a card fails, and what happens to their downloads when they cancel. That logic is a weekend of careful work, and getting it wrong means either giving away the library or locking out a paying member.
Exhibit A — The prompt
Received on31.07.2026Build a membership storefront for one creator: monthly access to a growing library of files.
Catalogue: files with a title, description, tags, and a release date. A file belongs to one or more tiers. Storage is S3-compatible; nothing is ever served from a public URL.
Subscriptions: Stripe Billing in hosted-checkout mode, one price per tier. Create the subscription server-side and handle everything else in webhooks — never grant access on the success redirect. Handle these events explicitly and write a test for each: subscription created, invoice paid, invoice payment failed, subscription updated (tier change), subscription deleted, and charge disputed.
Entitlement, which is the part that must be right. Store an entitlement row per member per tier with a start date and an end date, never a boolean. Access to a file is granted if the member holds an entitlement covering today. On payment failure, do not revoke immediately: mark the entitlement as in-grace until Stripe's retry schedule is exhausted, and show the member a banner with a link to update their card. On cancellation, entitlement runs to the end of the paid period and then stops. On tier change, prorate through Stripe and update the entitlement's tier without a gap.
Member area: browse the library filtered to what the member's tier covers, with signed download URLs valid for one hour. A what's-new view since their last visit, since that is the reason a membership feels worth keeping. Email on each new release to the tiers that can reach it.
Operator views: member list with subscription state, revenue per month, churn count, an immutable event log of every webhook processed, and a manual grant-or-revoke action with a required reason.
Tax: do not calculate, collect or remit VAT. State in the README and in the admin interface that the operator is the seller of record and that digital subscriptions to EU buyers create a VAT obligation from the first sale.
Out of scope: physical products, print-on-demand, one-off purchases, affiliate tracking, and a public marketplace.Opening prefills the prompt — press enter to run it.
Exhibit B — What you lose
- B.1 VAT collected and remitted for you on EU and UK sales
- B.2 print-on-demand merchandise, printed and shipped without you
- B.3 the hosted storefront themes and their mobile checkout
- B.4 cart-abandonment and upsell flows
Prior art
Exhibit C — Why people still pay: payments, tax, distribution, and operations
Because a membership that breaks is a refund request, and the fiddly parts — dunning, proration, reactivating a lapsed member without them losing their place — are exactly what a platform has already debugged.
Questions
Can I move my Sellfy customers across?
Products and files move by hand. Active subscriptions are the hard part: Stripe can migrate subscriptions between accounts in some cases, but if Sellfy is the merchant of record then your members have to re-subscribe, and some will not. Plan the switch around a renewal date.
What happens when a member's card fails?
The prompt puts them in a grace period rather than cutting access at once, because Stripe retries a failed invoice over roughly two weeks. Revoking on the first failure is the single most common way a self-built membership loses paying customers.
What does it cost to run?
Stripe's percentage plus a small VPS with PostgreSQL, so five to ten dollars a month plus object storage measured in cents per gigabyte. Against Sellfy's Starter plan this pays for itself quickly, provided you never have to spend a weekend debugging entitlements.
What is the one thing that does not survive the rebuild?
Being the merchant of record. Sellfy handles EU and UK VAT on digital sales; self-hosting makes that yours from your first European member, which is a registration rather than a line of code.
Related tools
Receipt