The short answer
Buy now pay later software development is the build of a platform that lets a shopper split a purchase into instalments while the merchant is paid up front, less a fee. A working BNPL platform has six parts: a checkout integration merchants add by plugin or API, an instalment plan engine for pay in 4 and monthly plans, a credit and affordability check at the point of sale, merchant settlement and reconciliation, missed payment and late fee rules set to local law, and a customer app for repayments.
Growth Informer Software Services, based in Kampala, Uganda, builds these platforms for retailers and fintechs from the US and UK to Africa. In African markets the same schedule engine can run pay-as-you-go device and asset financing: a deposit, then small daily or weekly payments by Mobile Money. A first release is priced against a fixed quote agreed before work starts, paid on a 50/25/25 plan, and you own the source code and the data.
What a BNPL platform has to do
Splitting a basket into four payments is the easy part. The real work is keeping the merchant, the customer and the ledger in agreement after a partial return, a failed card and a late fee. These are the modules we scope for a first release.
Merchant checkout integration
Merchants add your instalment option in one of two ways. A plugin suits smaller shops, but check each platform's rules first: WooCommerce accepts third party payment plugins, while Shopify only opens its Payments Apps API to approved payments partners, who must meet technical requirements such as idempotent requests and mutual TLS. Plan for that approval before promising Shopify merchants a launch date. An API with sandbox keys, signed webhooks and clear documentation serves larger retailers and marketplaces that run their own checkout. Both routes use the same core calls: create a checkout session, return a decision, confirm the order when it ships, then refund or cancel. If you are also building the storefront, see our ecommerce platform development service.
Instalment plan engine
The engine turns a basket into a schedule. A typical pay in 4 plan splits the total into four equal payments, the first at checkout and the other three every two weeks, so the plan ends six weeks after purchase. Monthly plans run longer and may carry interest or a fixed fee. Every plan type is configuration rather than code: term, frequency, deposit, minimum and maximum basket, merchant fee and grace period. Rounding is settled when the plan is created so the instalments always add up to the basket, and a partial return reduces the remaining instalments by a rule you choose instead of breaking the schedule.
Credit and affordability checks
The decision has to come back while the shopper is still at checkout. We build a rules engine that combines your own data (repayment history, basket size, merchant category, identity checks) with the credit bureau or data provider you contract with. In the UK this step now carries regulatory weight: since 15 July 2026 the FCA has required lenders of deferred payment credit to check that a customer can afford to repay before the agreement is made. Rules, limits and scorecards stay editable by your risk team, and every decision is stored with its reasons, so you can explain it to a customer, an auditor or an ombudsman.
Merchant settlement and reconciliation
Merchants receive the order value less your merchant fee on a payout schedule you set, and a refund issued after payout is netted from that merchant's next settlement. Every movement posts to a double-entry ledger with separate accounts for merchant payables, customer receivables, fees, refunds and chargebacks. Finance gets a daily reconciliation against your bank or payment gateway statement, with breaks flagged rather than buried.
Missed payments, late fees and collections
Retries, reminders, a block on new purchases and late fees are all rules: how many retries, how many days of notice, a cap per missed instalment and a cap per plan. The caps differ by market, and some regulators are still setting them. New York's Department of Financial Services, for example, has proposed limits on late fees under the state's 2025 BNPL law. The software enforces the limits you configure, logs every notice and fee, and lets your team pause fees for a customer in financial difficulty. Setting the limits correctly is the lender's job, with your own legal advice.
Customer app and back office
Customers see every plan, balance and next due date, pay early, change a card or Mobile Money number and raise a dispute. Plan for app store review early. Apple asks that financial services apps be submitted by the legal entity that provides the service. Apple and Google Play both reject personal loan apps that require repayment in full in 60 days or less, and Google Play bars personal loan apps from reading contacts or photos, so we check how review is likely to classify your six week plans before submission and never request those permissions. Your team gets a back office for merchant onboarding, credit limits, disputes, refunds and reporting. If you also offer longer term loans, the schedule and ledger can share a core with loan management software.
From the US and UK to Africa: one engine, local rules
The instalment logic is the same everywhere. What changes by market is how money moves, how credit is checked and which regulator the lender answers to. We build each country as configuration, so adding a market means new payment rails, disclosures and fee limits rather than a rewrite. These are the rules shaping BNPL builds in 2026.
- United Kingdom: the FCA began regulating deferred payment credit on 15 July 2026. That covers interest-free credit repaid in 12 or fewer instalments over 12 months or less, provided by a third-party lender through a merchant. Those lenders need FCA authorisation or temporary permission, affordability checks and a complaints process that can end at the Financial Ombudsman Service. Card repayments run through your payment gateway, with Direct Debit where your provider supports it.
- United States: in May 2025 the CFPB withdrew its 2024 interpretive rule that treated BNPL lenders like credit card providers, which puts more weight on state law. New York enacted a BNPL licensing law in 2025, and its Department of Financial Services proposed implementing rules in February 2026, including limits on late fees. Plan rules should switch by state, with card and ACH repayments.
- Kenya and Nigeria: Kenya's Business Laws (Amendment) Act 2024 brought non-deposit-taking credit, including BNPL and asset financing, under Central Bank of Kenya licensing. Nigeria's FCCPC digital consumer lending regulations of 2025 require approval before lending to consumers online. Google Play also asks personal loan apps in both countries for licence documentation. Repayments run on Mobile Money where customers use it, with SMS reminders for customers who never open an app.
- Pay-as-you-go device and asset financing: across much of Africa the thing bought on instalments is a phone, a solar kit or a motorbike. The model is proven at scale by M-KOPA, which finances smartphones in Kenya, Uganda, Nigeria, Ghana and South Africa with a small deposit, daily or weekly Mobile Money payments and remote locking. Our engine handles the deposit, a daily schedule and lock status tied to payments, through whichever lock tool your handset supplier supports, such as Google's Device Lock Controller, which is enabled through device maker partnerships.
Whatever the market, licensing, cost disclosures and the treatment of customers in arrears are your obligations as the lender. We build the controls, disclosures and audit trails your compliance adviser specifies, on the same kind of double-entry ledger with Mobile Money and USSD that runs under our own wallet, Moyo Pay.
What BNPL platform development costs
Every project gets a fixed quote before work starts, paid on a 50/25/25 plan. The ranges below are shown for your region and are typical for each scope. Your written quote replaces them once we have mapped your build.
| Scope | Typical price | What is included |
|---|---|---|
| BNPL core platform | Instalment plan engine, credit and affordability rules, double-entry ledger, merchant checkout API, settlement, reconciliation and back office | |
| Payment gateway or Mobile Money integration | Card, bank debit or Mobile Money repayments, signed webhooks and automatic retries | |
| Customer app, iOS and Android | Plans, balances, early repayment, payment method changes, disputes and reminders | |
| Ecommerce storefront with instalments at checkout | The shop itself, for a retailer financing its own sales. The instalment engine is priced in the core platform row | |
| Monthly support retainer | Updates, security patches, rule and fee limit changes, and new merchant integrations |
What moves the quote
- Merchant model: one retailer financing its own checkout is far simpler than an open network with merchant onboarding, fees and payouts.
- Plan types: pay in 4 alone ships sooner than pay in 4 plus interest-bearing monthly plans and pay-as-you-go asset financing with device locking.
- Checkout channels: a direct API, a WooCommerce plugin and a Shopify payments app are separate deliverables, and the Shopify route adds partner approval work.
- Credit data sources: each bureau, open banking or Mobile Money data feed is its own integration.
- Markets: each country adds payment rails, disclosures and fee limits. A UK launch needs affordability checks and complaint records ready from the first live order.
When you should not build custom BNPL software
Custom is not always the right call, and we will tell you so before you spend anything.
- You are a retailer that only wants to offer instalments. Adding an established BNPL provider at checkout is faster and leaves the credit risk with the provider. That is a payment integration job, not a platform build.
- You have not tested demand. Pilot pay in 4 on your own store or with a handful of merchants before funding a network with onboarding and payouts.
- You have no funding line for the receivables. The software is the smaller cost. Every order you finance ties up capital until the last instalment clears: six weeks on a pay in 4 plan, months on a monthly plan.
- You have not settled your licensing route. In the UK the new FCA regime covers third-party lenders, not merchants that offer deferred payment credit directly, and in Kenya BNPL falls under Central Bank of Kenya licensing. Take legal advice first, because the route decides which checks and disclosures the software must carry.
Custom makes sense when BNPL is your product rather than a feature: you want to own the credit decision, set your own merchant fees, keep the data and reach customers existing providers do not serve well, such as Mobile Money users and pay-as-you-go asset buyers. If instalments are one product among several, a wider digital lending platform may serve you better. If you run a loan book with savings and shares rather than checkout instalments, look at the Growth Informer Loan and SACCO Management System, which we configure and build for each lender.
How we build it, and what we can show you
BNPL builds go wrong when the screens are built before the money is right. We work the other way round, and we are plain about what we have and have not built before.
How a BNPL build runs
- Scope: we map your plan types, merchant model, launch countries, credit data sources and checkout channels, then send a written scope with a fixed quote.
- Ledger first: the ledger, schedule engine and settlement rules are built and tested against worked cases (a full refund, a partial return, a failed payment, a late fee, a refund after merchant payout) before any screens, because every later feature depends on those numbers.
- Sandbox, then pilot: merchants test the plugin or API against sandbox keys, then a small live pilot runs before wider rollout.
- Handover: you receive the source code, the data and the documentation, and you own all of it.
What we have actually built
Our fintech proof is our own products, not a lender's case study, and we have not yet shipped a production BNPL or loan system for a client. Moyo Pay is our dual-currency wallet on a double-entry ledger with Mobile Money and USSD. Growth Informer Business is our live cloud POS, inventory and business platform, the kind of sales and stock system a retailer's instalment offer sits on top of. Karibu is a travel SaaS. You can see 37 live website and app builds on our portfolio. The team works on East Africa Time (UTC+3), which overlaps the UK and European working day.
Frequently asked questions
How much does BNPL software development cost?
A core BNPL platform with the instalment engine, credit and affordability rules, ledger, merchant settlement and back office is typically priced . The customer app and payment gateway or Mobile Money integration are priced separately. You get a fixed quote before work starts and pay on a 50/25/25 plan.
Can BNPL repayments be collected by Mobile Money?
Yes. The engine treats Mobile Money as a repayment method alongside cards and bank debits, with retries and SMS reminders, and supports the daily or weekly schedules used in pay-as-you-go device financing. Our own wallet, Moyo Pay, is built on a double-entry ledger with Mobile Money and USSD.
Will the software make us compliant with BNPL regulation?
Software alone cannot. Licensing, affordability standards, disclosures and fee limits are the lender's obligations, such as the FCA rules for deferred payment credit in the UK since 15 July 2026 or Central Bank of Kenya licensing for BNPL. We build the checks, fee caps, notices and audit trail your legal adviser specifies, and keep them configurable as the rules change.
Have you built BNPL platforms for clients before?
Not for a client in production yet, and we will not pretend otherwise. Our fintech proof is our own products: Moyo Pay, a dual-currency wallet on a double-entry ledger with Mobile Money and USSD, and Growth Informer Business, our live cloud POS, inventory and business platform. You can review 37 live website and app builds on our portfolio.
Do we own the source code?
Yes. You own the source code and the data, so you can host the platform where your lender licence or bank partner requires, bring in another team or keep working with ours.