Marketplace development: what to build first, and what to buy
Phil McParlane, founder of Sellframe
Published 31 October 2026
A marketplace is a website or app that brings two groups together: guests and hosts, homeowners and tradespeople, employers and job seekers. Marketplace development is harder than building a shop, because you build for two sets of users at once, and neither turns up without the other.
We design, build and run directories and marketplaces as part of our web app development work, and run a two-sided job board of our own. Nothing here is legal or tax advice; where a rule applies, we link to the regulator's own words.
The chicken-and-egg problem
A marketplace with ten listings looks empty to a buyer, and one with no buyers isn't worth a seller's time. Start with the side that is harder to get, usually supply, and make the marketplace useful to it before the other side arrives. These approaches work, alone or together:
- Bring in listings that already exist. 4dayweek.io, the job board for four-day weeks that we built and run, doesn't wait for employers to post. Alongside the jobs they post themselves, its collector reads more than 1,300 company job boards six times a day. If you gather listings from elsewhere, check each source's terms first.
- Give one side a tool worth having on its own. A booking calendar or a quoting tool that sellers would use with no buyers yet means the supply is already there when buyers arrive.
- Do it by hand first. Match the first buyers and sellers yourself, by email and phone, before you build any matching. Our guide to what an MVP is and what to put in yours covers this kind of manual first version.
- Go narrow. One category in one city fills up far faster than every category everywhere.
- Let search bring the other side. Pages made for specific searches, such as one service in one town, bring buyers from Google. 4dayweek.io publishes such a page only once it has 20 matching jobs, and archives it after 30 days empty. In the 90 days to 15 October 2026, the site had 152.7k clicks from Google search.
If you are a business adding a marketplace, you may already have one side: your customers, or the suppliers you buy from. That is a large head start, and the first thing to design around.
Build or buy
Hosted platforms such as Sharetribe give you the standard parts on day one. Its features page lists listings for rentals, services or products, location or keyword search, messaging between customers and suppliers, reviews collected after every paid transaction, payments through Stripe in 26 countries, automatic payouts to the supplier once a transaction is over, and a commission you set. As of October 2026, its pricing page lists, in US dollars before VAT, a Build plan at $39 a month, which runs in test mode only, and a Live plan at $199 a month billed yearly or $259 billed monthly. Sharetribe charges no transaction fees, though usage above a monthly allowance is billed separately, and Stripe charges its own fees on each payment. You can change the marketplace with code, but then you host the front end yourself.
Start on a platform when your marketplace follows a common pattern, such as booking a rental, hiring a service or buying a product, and the open question is whether anyone wants it: you find out sooner, for far less than a build. Before you commit, check how you would get your listings, users and transaction history out.
Build your own when what makes your marketplace different is the software itself: unusual matching, data no platform holds, or a transaction that doesn't fit book or buy. On 4dayweek.io, the hard part is reading thousands of job ads accurately: an AI service reads each ad for the role, the location and the salary, and a guard drops implausible salary figures. Build too when the marketplace has to work inside an existing business, with its stock, accounts and customer records. Our post on bespoke software examples and when to build one has a wider build-or-buy test.
The parts every marketplace needs
Whether you buy or build, you need these parts.
| Part | What to get right |
|---|---|
| Listings | Required fields that match how buyers decide, and a way to retire stale listings |
| Search and filters | Only the filters that matter in your niche, and no dead-end empty results |
| Trust and reviews | Seller checks before going live, and review moderation (see the rules below) |
| Messaging | Email notifications, so a question doesn't sit unanswered |
| Payments and payouts | Refunds, disputes, and who carries the loss when something goes wrong |
| Admin | Approving sellers, removing listings and reviews, and handling reports |
Stale listings lose trust fastest. On 4dayweek.io, any job not seen in a scrape for seven days is hidden from job seekers, and a job is expired once its own link is confirmed dead. We also chose to show no salary rather than an estimated one, because a wrong figure misrepresents a real employer.
The UK and EU rules that bite
Payments: let a provider split them
Stripe Connect is one payment service built for marketplaces. In its guide to building a marketplace, customers pay the marketplace, which pays the sellers and keeps an application fee, and Stripe handles seller onboarding. The marketplace pays Stripe's fees, manages disputes and refunds, and covers any seller's negative balance. Stripe's page on how charges work in Connect says destination charges suit marketplaces such as home rentals, and separate charges and transfers suit splitting one payment between several parties, such as one basket of goods from several sellers.
Taking buyers' money into your own account and paying sellers later can bring you under the Payment Services Regulations 2017. One of the payment services they list is money remittance, which covers funds received from a payer for the sole purpose of transferring a corresponding amount to a payee. The FCA says a business that provides payment services as a regular occupation or business activity in the UK must apply to be authorised or registered, unless it is already another type of payment service provider or is exempt. Whether your model is in scope is a question for a lawyer.
Reviews: the duty sits with you
The Digital Markets, Competition and Consumers Act 2024 bans fake reviews, reviews that hide an incentive, and publishing consumer reviews in a misleading way. The CMA's fake reviews guidance, published on 4 April 2025, names online marketplaces among the publishers that must take reasonable and proportionate steps to prevent and remove them. Every publisher needs a clear policy and an assessment of the risks and, where there is a risk, ways to detect, investigate and act on suspect reviews.
The guidance's own examples translate into features:
- Rules on who can leave a review, such as checking the reviewer used the product, without shutting out someone who received it as a gift.
- Records that show patterns, such as different reviewers sharing an email or IP address, or a sudden spike in very positive or negative reviews.
- A public way to report a suspect review.
- A way to keep a review under investigation out of the overall rating.
It also warns that removing a genuine negative review can mislead as much as publishing a fake positive one.
Tax: platforms report what sellers earn
New rules started in the UK on 1 January 2024. They apply to a digital platform resident, incorporated or managed in the UK that connects sellers to customers and holds, or can easily calculate, what sellers are paid. For an individual seller, the platform collects and checks their full name, home address, date of birth and tax identification number (the National Insurance number for someone living in the UK). Platforms report to HMRC each seller's details and income by 31 January for the previous year, and give each seller a copy. Sellers of goods who get 2,000 euros or less (about £1,700) for fewer than 30 sales in a year are left out, but that exception doesn't cover services or rentals.
So collect these details when a seller signs up, not in a scramble each January, and keep a running total for each seller.
If your marketplace reaches the EU
The EU's rules, DAC7, entered into force on 1 January 2023. Platforms report on sellers resident in the EU who sell goods, provide personal services, or rent out property or any mode of transport. Under the Digital Services Act, marketplaces must also verify and display sellers' contact details.
What to build first
Build the smallest version that completes one real transaction, from listing to review, in your narrow niche. For most marketplaces, that means:
- Seller sign-up that collects what the tax rules need, and an admin check before a seller goes live.
- Listings with the few fields buyers really choose on.
- Search with only the filters your niche needs.
- Enquiries or messaging, with email notifications.
- Payments through a marketplace payment provider, if the deal happens on your site. If it happens elsewhere, as an application does on a job board, leave payments out at first.
- Reviews with a published policy, a report button and an admin queue.
Leave native apps, recommendations, several currencies and loyalty schemes for later. From the first week, watch how many searches find a match, how many listings get an enquiry, how quickly sellers reply and how many buyers come back. Those tell you which side to work on next.
If you want a hand
If your marketplace needs software of its own, or has to work inside an existing business, that is work we do. Start a project and tell us which side you would start with.