Web applications, mobile apps, backend platforms, payment software, embedded systems and integrations. Paying.co designs, builds, tests and ships software for new products, existing applications and teams that need more engineering capacity.
Payments are where our engineering is deepest, and the same discipline applies across the rest of the stack.
Customer portals, admin tools and internal systems built to run in production.
Android and cross-platform apps, including payment-enabled apps on terminals and phones.
Mobile app development →APIs, services and data layers that sit behind your apps and devices.
Terminal apps, processor connections and payment flows, built with certification requirements in mind.
Software for connected and unattended devices, where hardware, firmware and payments meet.
Connections between your software, payment gateways, processors and third-party platforms.
Integration services →Most engagements fall into one of four situations. If yours is a mix, we scope it that way.
You have a problem and a market. We design the architecture and build the first production version.
New features, reliability work and testing for software that is already in the field.
Explore the payment application testing checklist →Move aging applications forward in stages, keeping what works.
See how to modernize a legacy payment application without rebuilding everything →Bring in a team that already knows payments, so your own engineers can stay on the product.
See how payment engineering teams work alongside yours →Every engagement is scoped in a Statement of Work before development begins, so the plan, the milestones and the deliverables are agreed up front.
Define the problem, the users, the constraints and what success looks like.
Choose the stack, design the system and identify integration and certification dependencies.
Build in milestones, with working software you can review along the way.
Verify behavior against the requirements, including failure and edge cases.
Release to production with support for rollout and handover.
Deliverables are defined in the Statement of Work for each engagement.
The code for what we build, delivered to you.
Written so your team can operate and extend the software.
Records of what was tested and how.
Help getting the software into production.
Clear terms on who owns the code and the IP.
Real engineering work, described without client names.
A kiosk application for a venue that sells tickets, takes card payment through a payment gateway and prints physical ticket stubs on site.
Built with: Electron, Datacap gateway integration, ticket printer integration.
A cross-platform mobile app for a dental practice, built around offering patients financing for their care.
Built with: React Native.
Practical articles from the engineers who build this software.
Compare a dedicated payment engineering team with hiring in-house.
ModernizationSee how to modernize a legacy payment application without rebuilding everything.
Testing and reliabilityExplore the payment application testing checklist.
IntegrationsUnderstand payment gateway integration scope, timelines, and dependencies.
When your workflow doesn't fit a stock terminal app. Multi-step transactions, a specific hardware combination, a legacy protocol like MDB or Pulse, or a processor integration nobody else has built, that's when custom development is the right call instead of trying to bend an off-the-shelf product around your business. If a stock app genuinely covers your case, we'll tell you that instead of selling you a build you don't need.
Native Android development across Ingenico, PAX, Verifone, Clover, and ID TECH hardware, plus SoftPOS and unattended form factors. We've shipped 300+ terminal apps across this hardware range, so the question is rarely whether we can build on your device, it's what the app needs to do on it.
They're related but distinct workstreams, and we run both. Custom development builds the application; EMV Level 3 certification is the processor and card-brand approval process the finished application goes through. When a project needs both, we scope them together in the same engagement so the app is built with certification requirements in mind from day one, instead of discovering compliance gaps after the fact.
It depends entirely on scope, a focused single-processor integration is a different timeline than a multi-processor, multi-region build. We scope every engagement with a fixed timeline and milestone-based billing before work starts, so you know the schedule going in rather than getting an open-ended estimate.
You do. Custom development work is delivered as your IP, not licensed back to you. That's a deliberate difference from vendors who build you into a dependency on their platform.
Every engagement runs on a fixed-scope Statement of Work, so pricing is quoted against your specific requirements rather than an hourly rate that can run long. We've delivered 900+ projects across a wide range of scopes, from a single processor integration to full multi-processor unattended platforms, ask for a scoping call and we'll return a fixed quote, not a range.
If you are integrating our own products, these are the places to start.
Share what you need built, the stack you are working in and where you are stuck. We will route the conversation to an engineer who understands the problem, not just the pitch.
Tell us about your project — we route you to the right specialist.
