Payment Software Development Services
Most businesses that take payments run money through more than one provider, and no provider's dashboard shows the whole picture. Our payment software development services build the layer between your providers and your product. It covers gateway integrations, routing, instant and bank rails, the ledger, reconciliation (matching your records against the provider's or bank's), payouts, and fraud and dispute tooling. Your acquirers, processors and banks keep the licenses and the settlement. We scope your first release in two to three weeks with the engineers who will build it, and the ledger and reconciliation design come first.
Payment Gateway Integration Services and the Ledger Behind Them
The ledger records each authorization, capture, refund, fee and payout as an entry you can trace. Reconciliation checks it against provider settlement files (the provider’s record of what it paid out). The money stays with your provider or bank.
If an orchestration platform (a vendor service that routes payments across providers) or your provider’s own routing already covers your needs, we integrate it instead of building it. Routing does not give you the ledger: once you run more than one provider, each sees only its own settlement, so the ledger and reconciliation are yours to own. In a 2025 merchant study by S&P Global’s 451 Research, 90% of merchants worked with two or more payment providers. With two or more providers, routing rules, fee logic and payout timing affect your margin. Custom payment software development pays off when those rules go beyond what a platform offers. Identity checks and transaction monitoring sit beside the payment layer and feed it; our guide to client onboarding and compliance software covers them.
Scoping takes two to three weeks at a fixed fee, with the engineers who will build the system. The documents scoping produces are yours to keep. The build runs in increments of two to four weeks, each one tested and shipped on its own. After launch, the build team stays on the system under a support plan agreed in scoping.
Payment Gateway Software Development From Checkout to Payout
Six kinds of payment software we build, each connected to the providers you already run on.
01
Payment Gateway Integration
Payment gateway integration services for card acquirers, processors and wallets, behind one integration layer. Adding a provider means an adapter (one connector per provider) and a routing rule, and checkout stays the same for your customers.
01
Payment gateway integration services for card acquirers, processors and wallets, behind one integration layer. Adding a provider means an adapter (one connector per provider) and a routing rule, and checkout stays the same for your customers.
02
Payment Orchestration and Routing
Routing rules by card type, issuer country, cost and provider health. A soft decline (a refusal that may pass elsewhere) retries on the next provider; a timeout is checked before any retry, so a payment is not charged twice. Hard declines are not reattempted. Fees and authorization rate per provider in one report.
02
Routing rules by card type, issuer country, cost and provider health. A soft decline (a refusal that may pass elsewhere) retries on the next provider; a timeout is checked before any retry, so a payment is not charged twice. Hard declines are not reattempted. Fees and authorization rate per provider in one report.
03
Fraud and Dispute Tooling
Velocity checks (limits on how often a card transacts) and risk rules run before authorization. Where you have no rules engine (software that applies your risk rules), we build the rules and an admin screen. We integrate 3-D Secure, a cardholder check that can shift fraud liability, into the authorization flow. A dispute workflow files evidence on time.
03
Velocity checks (limits on how often a card transacts) and risk rules run before authorization. Where you have no rules engine (software that applies your risk rules), we build the rules and an admin screen. We integrate 3-D Secure, a cardholder check that can shift fraud liability, into the authorization flow. A dispute workflow files evidence on time.
04
Instant and Bank Payments
FedNow integration and RTP access through your bank's API, plus ACH and wire in the US, and SEPA Instant and open banking payments in Europe. One internal message model with per-rail limit and reachability checks, so a transfer is handled the same way on each rail. ISO 20022 migration where needed.
04
FedNow integration and RTP access through your bank's API, plus ACH and wire in the US, and SEPA Instant and open banking payments in Europe. One internal message model with per-rail limit and reachability checks, so a transfer is handled the same way on each rail. ISO 20022 migration where needed.
05
Ledger, Reconciliation and Payouts
A double-entry ledger (each amount is recorded as a matching debit and credit) gives balances you can trace and reconcile to what each provider paid. Payouts to sellers and partners are scheduled and approved, instructed from the ledger and paid by the provider or bank holding the funds.
05
A double-entry ledger (each amount is recorded as a matching debit and credit) gives balances you can trace and reconcile to what each provider paid. Payouts to sellers and partners are scheduled and approved, instructed from the ledger and paid by the provider or bank holding the funds.
06
Gateway for Payment Companies
For payment companies and platforms acting as merchant of record. We build merchant onboarding (identity checks come from your vendor), a state machine (the allowed payment states) for authorize, capture, void and refund, and batch settlement to the acquirer.
06
For payment companies and platforms acting as merchant of record. We build merchant onboarding (identity checks come from your vendor), a state machine (the allowed payment states) for authorize, capture, void and refund, and batch settlement to the acquirer.
What Our Payment Processing Software Development Includes
Scoping and Payment Flow Design
We sit with your finance, support and engineering leads and trace each provider connection and the data it sends. We ask how money moves through your setup today and what you want the first release to cover. Scoping produces six documents. The payment flow map shows which system holds each record and which messages move a balance. The others are an integration list with an owner for each connection, a data model, a risk list, a build estimate and a support plan.
Integration Reliability
Where the provider supports it, each request carries an idempotency key (a unique ID that makes a repeated request count once), to avoid a second charge on a retry. A timed-out authorization is checked by a status query or a void before any failover. Each webhook (a message a provider sends when something changes) is verified, stored and replayed, and a missed one is recovered by a status query. A provider's API change is handled inside its adapter.
Routing Rules and Change Control
Routing rules and risk rules are stored as configuration with version history. Your payments team changes a rule in an admin screen (ours, where you have no rules engine). A second person reviews it, and the previous version can be restored at once. New rules are replayed against recorded, tokenized traffic before go-live, and a replay report shows which transactions would have moved and the fee difference. Each rule decision is logged with its inputs and reason.
Ledger and Reconciliation
The ledger is double-entry with an append-only log (entries are added and not edited). Scheduled matching against provider settlement and payout files posts fees and currency conversion differences. It opens a ticket for each break (a mismatch found in reconciliation) with both records attached. A month-end close then exports matched entries to your accounting system. The ledger itself feeds support tools and your product's balance screens in real time.
Security and Card Data Scope
Scoping picks from tokenization (card numbers replaced by stand-in values), a vault (a secured store for card data) and a provider's hosted fields (card fields the provider serves). Scoping picks the mix. Tokenization and hosted fields keep card data out of your systems. A vault stores card numbers in one isolated place, stays in PCI scope and is used only when you must keep them. We build the tokenization or vault the choice calls for, plus script inventory (a list of the scripts on the payment page) and tamper detection. Access control, secrets management, encryption and audit logs on each action that touches money or card data are documented for your assessor.
Testing, Monitoring and Operations
Automated tests cover each money flow, including refunds, partial captures, chargebacks and payout reversals. They run against provider sandboxes and the replayed traffic described under routing rules, with card data tokenized. Monitoring alerts per provider on a drop in authorization rate, a rise in latency or failed webhooks. Releases go out in stages by merchant or customer group, with a rollback plan for each stage. The build team keeps a runbook for each incident type.
We sit with your finance, support and engineering leads and trace each provider connection and the data it sends. We ask how money moves through your setup today and what you want the first release to cover. Scoping produces six documents. The payment flow map shows which system holds each record and which messages move a balance. The others are an integration list with an owner for each connection, a data model, a risk list, a build estimate and a support plan.
Our Case Studies
Hola Salud
Hola Salud
Digital healthcare platform for Mexico.
We built a complete healthcare ecosystem, including a patient app, a doctor’s portal, and an admin backend, with self-registration, appointment booking, medical records, and integrated Stripe and Oxxo payments.
Environmental AI
Environmental AI
Environmental compliance automation.
We built a RAG-based system that automates environmental assessment documents and regulatory templates, cutting preparation time by up to 90%.
Revvel
Revvel
AI-powered women’s health platform.
We developed an AI platform that turns elite health experts into digital twins and reviews years of patient data in under 60 seconds, delivering risk assessments up to 10x faster and cutting time-to-care from days to minutes.
InnerPeak.AI
InnerPeak.AI
Student mental wellness platform.
We developed a comprehensive web and mobile application that provides students and teachers with 24/7 personalized support and engaging resilience training to build essential life skills.
Hello, We Hire
Hello, We Hire
AI-driven recruitment automation platform.
We built an AI-powered recruitment system with automated pre-screening, real-time skills evaluation, and multi-stage verification that speeds up hiring by 94%.
Hola Salud
Hola Salud
Digital healthcare platform for Mexico.
We built a complete healthcare ecosystem, including a patient app, a doctor’s portal, and an admin backend, with self-registration, appointment booking, medical records, and integrated Stripe and Oxxo payments.
Environmental AI
Environmental AI
Environmental compliance automation.
We built a RAG-based system that automates environmental assessment documents and regulatory templates, cutting preparation time by up to 90%.
Revvel
Revvel
AI-powered women’s health platform.
We developed an AI platform that turns elite health experts into digital twins and reviews years of patient data in under 60 seconds, delivering risk assessments up to 10x faster and cutting time-to-care from days to minutes.
InnerPeak.AI
InnerPeak.AI
Student mental wellness platform.
We developed a comprehensive web and mobile application that provides students and teachers with 24/7 personalized support and engaging resilience training to build essential life skills.
Hello, We Hire
Hello, We Hire
AI-driven recruitment automation platform.
We built an AI-powered recruitment system with automated pre-screening, real-time skills evaluation, and multi-stage verification that speeds up hiring by 94%.
Flexible Developer Hiring Model
Your priorities define the way we work together — from how much control you want to the level of flexibility your project demands.
Team Augmentation
Quickly scale your workforce with skilled developers who integrate seamlessly into your in-house team, filling talent gaps and boosting productivity.
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Dedicated Development Team
A whole, cross-functional team working exclusively on your project, providing end-to-end development, management, and long-term support.
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Software Development Outsourcing
Delegate your entire project to our specialists and focus on business growth, while we handle development, delivery, and quality.
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Why Plus8Soft?
01
Experience
Multiplied by AI
Multiplied by AI
We blend deep engineering expertise with cutting-edge AI acceleration. By integrating intelligent tools into our workflow, we don't just write code—we engineer solutions faster and with higher precision.
02
Business-First
Transparency
Transparency
We look beyond the ticket. Our team operates with hyper-transparency, treating your budget and goals as our own. We align technical decisions with your business strategy to create real, measurable value.
03
Committed to
Overdelivery
Overdelivery
Meeting requirements is our baseline; exceeding them is our culture. Whether it's optimizing performance, refining UX, or anticipating future scalability, we consistently go the extra mile.
Payment Software Development FAQ
What does a payment software development company build that a payment provider does not?
Your provider owns acquiring or processing, the checkout, its dashboard and settlement to your bank account. You own what works across providers: routing, the ledger your balances come from, reconciliation against settlement files, payouts and disputes. A payment software development company builds that part. We are not a provider and do not hold funds; the money sits with your providers or your bank, and your ledger records and instructs it.
Should we integrate payment gateways or build our own?
Integrate when your product sells goods or services and needs to accept payments reliably through one or several providers. Payment gateway development makes sense when you are the payment company: a merchant of record, a platform that onboards its own merchants, or a processor with acquirer relationships. Most products need the integration layer first and a gateway later, if at all; scoping sets that order.
Can you integrate FedNow and RTP for instant payments?
Yes, through your bank's or a payments provider's API, since only participating institutions connect to the rails themselves. The two US instant rails do not interoperate, so a product needs both for full reach, with reachability lookup and per-rail limits. As of 2026, FedNow reports more than 1,800 participating institutions and RTP about 1,380. Both carry a $10 million network limit, and each bank sets its own cap at or below it. We scope and build dual-rail routing, request-for-payment flows (the payee-initiated flow on both rails) and returns. The reconciliation records an instant credit, an ACH credit and a wire as the same kind of ledger entry, tagged by rail.
Do you offer ISO 20022 migration services?
Yes. Fedwire moved to ISO 20022 in July 2025, CHIPS in April 2024, and SWIFT ended the MT coexistence period for cross-border payments in November 2025. The main high-value rails now share a message family. We design the message layer as native ISO 20022, with structured party and address data from the start. Legacy formats are mapped at the edge, so structured data is stored in full and truncated only where an older format forces it.
How do you keep card data compliance scope small?
By keeping card data out of your systems wherever the product allows. That means a provider's hosted fields or redirect, network tokens for stored cards, and a vault only when you need one. Only the systems that still touch card data stay in your cardholder data environment, plus the page that hosts the provider's form. We build and document controls against PCI DSS v4.0.1, including the script inventory and tamper detection requirements on payment pages that took effect in March 2025. Your assessor confirms the scope; we build and document the controls.
What changes for payments in the EU?
Since 2025, euro-area providers have had to receive and send instant credit transfers and check the payee name before each transfer (Verification of Payee). The remaining dates for payment institutions and non-euro countries fall in 2027. PSD3 and the Payment Services Regulation are in the final stage of adoption, and the dates they bring are tracked in the scope. We build the payee verification, consent and strong authentication flows your compliance team specifies. Your counsel decides what applies in each market.
Do you handle multi-currency and cross-border payouts?
Yes. Currency conversion happens at capture or at payout, by rule, and the ledger keeps the original and the settlement currency on each entry. Reconciliation posts FX differences and provider fees per currency, and payouts run through the provider or bank that holds the funds in the destination currency. Cross-border rails and the data each one requires, such as structured addresses and purpose codes, are mapped in the integration layer.
How long until our first release with Plus8Soft?
Scoping takes two to three weeks. The first release covers one flow, such as payouts or a second provider behind routing, and its timeline is a planning estimate, confirmed in the scope. After that, we release in increments of two to four weeks, each one tested on its own.
How do you price a payment software project?
Scoping is quoted as a fixed fee before it starts. The build estimate depends on the number of providers and rails, the flows in the first release, and how much of the ledger and reconciliation you already have. The estimate is confirmed before development starts.
Which technologies do you use?
Back end: Node.js with NestJS, Go and PHP. Data and events: PostgreSQL, and Kafka or the queue already in your stack. Front end: React, TypeScript and Next.js for web, React Native and Swift for mobile. Infrastructure runs on Docker and Kubernetes on AWS, and we work in your stack when you already have one.
Who owns the code?
The code we write for you is yours. We work under an NDA, with access limited to the repositories and environments the project needs, and hand over documentation and credentials when the engagement ends.
