Prototype a two-sided marketplace on one device before building the backend
A marketplace has two products in one: what buyers see and what sellers see, plus the trust and money that flow between them. Anticode can build a working prototype of both sides, with sample listings, on a single device, which is enough to test the flows and pitch the idea. The real marketplace needs accounts, shared listings, payments and messaging, none of which a sandboxed app can provide.
The marketplace problem a prototype can't solve
Marketplaces are hard because buyers come only when there are sellers, and sellers only when there are buyers. No software answers that, and it's worth being honest with yourself about it before building anything. Many successful marketplaces started with one side handled by hand: the founders found the first sellers personally, or listed supply themselves, and matched buyers by email. A prototype's role is narrower: to check that each side understands and wants the experience, and to show investors or early partners what it will be.
Map both sides' flows
| Buyer (renter) | Seller (owner) |
|---|---|
| Search and filter listings by area, date and price | Create a listing with photos, price per day and availability |
| View a listing with details, owner profile and reviews | See incoming requests and accept or decline |
| Request to book chosen dates | Agree hand-over details |
| Pay, with a deposit held | Get paid after the hire, minus the platform fee |
| Message the owner | Message the renter |
| Leave a review | Leave a review of the renter |
For a prototype, pick the two or three flows that carry the most risk. Usually that's the buyer's search-to-request path and the seller's listing creation, because those decide whether either side bothers to start.
Building a two-sided prototype
Ask for both sides in one app with a visible switch between them: "A marketplace prototype for hiring garden and DIY tools from neighbours. A toggle at the top switches between Renter and Owner views. Renter: search with area and date filters, listing page, request to book. Owner: create a listing, a requests inbox with accept and decline. Twenty sample listings with prices and owners, all marked demo data. Requests made in the renter view appear in the owner view."
Because both views run in the same browser, they can share the same local data: a request made as a renter really appears in the owner's inbox, and accepting it really changes the renter's booking status. That makes the prototype convincing in a demo and useful in testing, as long as everyone understands it's one device playing both parts. Listings and requests are saved in that browser, so a demo set-up survives a reload.
Listing photos are a practical snag. The sandbox can't load images from other sites, so listings use drawn illustrations or coloured placeholders made in code. For investor demos that's usually fine; say it's a prototype.
What needs a real backend
Every piece that makes a marketplace work between people requires a server, so none of it can exist in an Anticode app:
- Accounts for buyers and sellers, with verification and password recovery.
- Shared listings that every visitor sees, created by many sellers, with search over a real database.
- Payments: taking money from buyers, holding deposits and paying sellers minus a fee. That's a regulated area; providers such as Stripe Connect exist for it, and you'll need one.
- Messaging between buyer and seller, with notifications.
- Reviews and trust: reporting, moderation, dispute handling.
- Email: confirmations, reminders, receipts.
Where to go after the prototype
The Next.js export gives you a code base to build from: app builds included, in TypeScript, with Postgres through Prisma, email sign-in, customer and staff roles, row-level security, an audit log, an admin area with two-factor sign-in, and email through Resend. For a marketplace, a developer would add seller and buyer roles, listings and search, a payment provider's marketplace product, and messaging. That's a substantial project; the export saves the scaffolding, not the core work.
Other routes are worth weighing. Dedicated marketplace platforms handle accounts, listings and payouts out of the box, at the cost of flexibility. And for very early validation, a landing page for each side with an interest form, plus manual matching, can test demand before any marketplace software exists. Contact and newsletter forms in Anticode reach you for real, so a "list your tools" interest form is a genuine way to gather your first sellers.
Questions people ask
Can a marketplace app builder like Anticode run a live marketplace?
No. Anticode apps have no accounts, shared data or payments, so they can't run a marketplace between real people. They can prototype it convincingly.
Can investors try the prototype themselves?
Yes. Send the published link; each person gets the sample data on their own device and can switch between buyer and seller views.
Can I collect seller sign-ups while I prototype?
Yes. An enquiry or newsletter form in the app sends interested sellers' details to you by email and in your dashboard.