Services · Mobile app development · Online marketplace apps
Codeeo handles marketplace app development in the USA for founders, retailers and distributors who want many independent sellers trading under one brand. We build the buyer app, the seller app and the operator console, and we wire in the obligations that arrive the moment a third party lists a product: seller verification under the INFORM Consumers Act, marketplace facilitator sales tax in every state you ship to, split payouts and a dispute process your support team can actually run.
A marketplace is a different product from an online store. You hold no stock, yet buyers blame you when an order goes wrong, regulators expect you to know who your sellers are, and state tax agencies treat you as the retailer. The software has to carry that weight from the first release.
200+ companies across the US and the UAEFrom a first store to a listed developer
Platform components
Most marketplace failures we see are not design failures. They are operational gaps: a seller who cannot be paid because their tax details were never collected, a state that expected the platform to remit tax, a chargeback nobody could answer because the evidence lived in a seller's inbox. Our multi-vendor marketplace app development in the USA starts with those gaps and works outward toward the shopping experience.
The components below are the ones we scope most often. A consumer marketplace for handmade goods and a B2B parts exchange will weight them very differently, so we rank them with you in discovery rather than shipping every item by default. Anything left out of the first release is planned so it can be added later without rebuilding the data model, which matters most for tax records and seller history.
Sellers who cross the high-volume threshold in the INFORM Consumers Act must give the platform bank details, a tax identification number and contact information, which you then verify. We build automatic threshold tracking, collection prompts, the annual recertification reminder and the account suspension the statute requires when a seller stops responding.
You can show the FTC or a state attorney general what you collected and when.
Every state that levies sales tax now has a marketplace facilitator law, and most make the platform collect and remit on third party sales. We connect a tax calculation service so each order gets the correct state and local rate at checkout, and filing reports come out grouped by jurisdiction.
Tax is collected at the moment of sale instead of reconstructed at filing time.
One basket, several sellers, one card charge. We integrate a payments provider built for platforms so funds are split per seller, your commission is taken automatically and payouts follow a schedule you control. The provider holds the funds, which keeps you away from acting as a money transmitter yourself.
Sellers see what they earned, and your margin settles without manual transfers.
Whoever settles payments to sellers may owe the IRS a Form 1099-K for each one above the reporting threshold, a threshold that has moved several times recently. We store W-9 details, track gross payments per seller and keep the records your payments provider or accountant needs at year end.
Year-end reporting is a report, not a scramble through spreadsheets.
Structured listing forms per category, image rules, variant handling, prohibited item checks and search with filters buyers actually use. Operators can approve, hold or remove listings, and a report button lets buyers flag suspected stolen, counterfeit or unsafe goods, which INFORM also requires.
The catalog stays clean as the number of sellers grows.
Each order carries its own messages, tracking, return window and evidence. When a buyer opens a dispute or a card network sends a chargeback, the case collects seller replies, delivery proof and refund history in one view, with deadlines visible to your support staff.
Disputes get answered on time with the evidence attached.
Sellers manage stock, accept orders, print labels, reply to buyers and check payouts from their phone. Each one gets a storefront page with ratings, policies and the business details INFORM obliges you to show buyers for larger sellers.
Sellers can run their shop without calling your team.
Sellers in different states ship from different places, so each one sets handling times, carriers, free shipping rules and the states they will not ship to, for example where a product category is restricted. Buyers see delivery estimates per seller in the basket, and labels from USPS, UPS or FedEx accounts are printed from the seller app.
Buyers know what arrives when, before they pay.
For wholesale platforms we add company accounts with several buyers, approval limits, tax exemption certificates, quote requests and invoice payment terms alongside card checkout.
Trade buyers order the way their purchasing department already works.
Gross merchandise value by seller and category, fulfillment speed, dispute rates, refund rates and seller growth, so you can see which sellers lift the marketplace and which put it at risk.
Decisions about fees and seller standards rest on real numbers.
Who we build for
The obligations above apply to almost every platform, but the order in which they bite depends on your model. A consumer marketplace meets INFORM and sales tax first. A service marketplace meets worker classification questions. A wholesale exchange meets resale certificates and invoicing. Here is where each type usually starts with us. National rollout adds its own pressure: a platform that launches in Texas and later opens to buyers in California and New York crosses new tax registrations and stricter privacy rules on the way, so we plan those states into the data model from the start.
You already sell your own stock online and want to extend the range without buying more inventory. The difficult part is mixing first party and third party orders in one basket, with different tax treatment, fulfillment and returns rules. We extend your existing commerce stack where it is sound and add seller onboarding, payouts and facilitator tax handling around it, so your loyal customers notice more choice rather than a new platform.
Your current product data and customer accounts usually carry over.
Collectibles, vintage furniture, outdoor gear, local food producers: niche marketplaces live or die on trust between strangers. We design the first release around verified sellers, clear listings, protected payments and a fair dispute flow, and we keep the feature list short enough to launch and learn. Seller acquisition tools come next, once you know which sellers bring repeat buyers.
Liquidity matters more than features in the first months.
Online marketplace app developers in the USA often treat B2B as consumer checkout with bigger quantities. It is not. Buyers need net terms, purchase order numbers, tiered pricing, exemption certificates and several approvers. We build those flows and connect them to your ERP or accounting system so orders flow into fulfillment and invoicing without rekeying.
Resale certificates are stored per buyer and per state.
Booking cleaners, tutors, tradespeople or creatives adds scheduling, quotes, deposits and reviews to the usual marketplace stack. It also raises questions about how providers are classified under federal and state rules, which your lawyer should answer before launch. We build the product so that controls such as pricing and scheduling sit where your legal advice says they should.
We build to your counsel's classification decision, not around it.
Working with Codeeo
Codeeo has delivered 200+ projects across the UAE and the US, with a team of 80+ across Dubai, Riyadh and Karachi. We work remotely with American clients, running discovery, design reviews and sprint demos by video call. Most marketplace clients start with a fixed scope first release, move to a monthly retainer once sellers are trading, and a few take a dedicated team when the platform becomes the core of the business.
A defined build with a deadline
We agree what the product has to do, write it down with a price and a date, and build exactly that. Changes are priced before they are made, not discovered on the invoice.
A product that keeps evolving
Named engineers who work your hours, join your standups and stay on the codebase. You direct the backlog; we own the quality of what ships.
Something live that needs looking after
A monthly block of hours for improvements, fixes and the small requests that otherwise wait months. Unused hours carry for a quarter.
Technology
Native or cross platform mobile apps, a web storefront for search traffic, and a backend designed around a double entry ledger so every commission, refund and payout can be traced. Payments, tax and identity checks come from established US providers rather than custom code, and every seller record keeps a dated history of changes for audits.
01Mobile
02Data and cloud
03Marketing and tracking
It depends mostly on payments, tax and how many seller types you support.
A focused first release with one seller type, card payments through a platform payments provider and a tax calculation service is far quicker than a launch with B2B terms, several categories and custom payout rules. We agree the launch scope in discovery and then commit to dates in writing. The pieces that most often extend a schedule are third party approvals, such as payments provider onboarding and app store review, so we start those early.
Schedule a free consultation and get a written recommendation, with costs, before you commit to anything.
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