Software payment processing

Software payment processing — SDKs and APIs for every stack.

topropay ships server SDKs for Node, Python, PHP, Java, Go and .NET, native mobile SDKs for iOS and Android, and an OpenAPI-described REST surface for everything else. One software footprint covers card, ACH, BNPL, regional APMs and (via partner gateways) crypto.

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install.sh
  1. Node $pnpm add @topropay/node
  2. Python $pip install topropay
  3. PHP $composer require topropay/php
  4. Java $implementation 'com.topropay:sdk:1.x'
  5. Go $go get github.com/topropay/go
  6. .NET $dotnet add package Topropay
Same authorisation engine across every SDK.
6+ SDKs
server-side language coverage
iOS+AND
native mobile SDKs
OpenAPI
spec for any other stack
1 API
across card, ACH, crypto

Key benefits

Why orchestrated payment software solutions win on every axis

Four outcomes that show up consistently once the payment software stack is orchestrated through one SDK family rather than glued together from per-provider libraries.

  1. 01

    Payment software your stack already speaks

    Server SDKs for Node, Python, PHP, Java, Go and .NET wrap the REST surface with idiomatic helpers, response types and webhook-signature verification. Mobile SDKs for iOS and Android share the same authorisation engine. Anything outside that list calls the OpenAPI-described REST directly.

  2. 02

    Split-payment routing built in

    Split-payment gateway behaviour — splitting an authorisation across multiple sellers, applying platform fees, holding funds in escrow — is exposed through the same API as a one-off authorisation. Marketplaces and platforms don't bolt on a second tool for split payments.

  3. 03

    Card, ACH and crypto behind one contract

    Credit card payment software, ACH payment software, electronic payment software and crypto payment processing (via partner gateways) all sit behind the same authorise endpoint. The merchant changes a method field; the engine handles the rail-specific work.

  4. 04

    Secure payment software with PCI scope minimised

    Card data captures into the PCI DSS Level 1 vault before it ever touches the merchant's origin. Refunds, retries and recurring run on vault tokens. The merchant inherits the service-provider posture rather than carrying it themselves.

How it works

From SDK install to live software payment gateway in five stages

Five concrete stages between package install and a daily reconciliation export finance can close the month against. Most teams reach the live stage in days on the hosted path, weeks on the embedded path.

  1. 01

    Install the SDK for your language

    Server SDKs install via the language's standard package manager — pnpm, pip, Composer, Maven, Go modules, NuGet. Mobile SDKs install via CocoaPods / SPM (iOS) and Maven / Gradle (Android).

  2. 02

    Drop in API keys and webhook URLs

    Per-environment API keys (sandbox + live) plus webhook URLs configured from the dashboard. The SDK handles HMAC signature generation outbound and signature verification on incoming webhooks.

  3. 03

    Authorise via one endpoint, every method

    Cards, ACH, BNPL, regional APMs, crypto — all POST to /v1/payments with a method field. The SDK exposes idiomatic helpers per language; the wire shape is identical.

  4. 04

    Capture, refund and dispute via the same SDK

    Captures, partial captures, refunds and dispute responses live in the same SDK surface as authorise. Method-specific quirks (NACHA R-codes for ACH, BCB end-to-end IDs for PIX, network tokens for card recurring) are abstracted out.

  5. 05

    Receive signed webhooks and reconcile

    Signed webhooks fire on every state change; the SDK's verify helper checks the signature and parses the payload into a typed event. Reconciliation lives in a daily export the merchant pulls into ERP or warehouse.

Main use cases

Where orchestrated payment software earns its keep

Six merchant shapes that share the same SDK family but stress it differently — from DTC retail to ACH-heavy B2B and split-payment marketplaces.

  • DTC

    DTC and online retail

    Credit card payment software inside the merchant's existing checkout — the language-native SDK calls the authorise endpoint, the hosted fields render the form, the webhook handler updates the order.

  • Plat

    Marketplaces and platforms (split payment gateway)

    A split payment gateway flow on the SDK — one authorise call with a split-array body, the platform routes the funds per seller and applies the platform's fee. Per-seller payouts settle into a single reconciliation feed.

  • SaaS

    Subscriptions and SaaS

    Recurring billing on vault tokens through the same SDK that handles the initial authorisation. Cycle scheduling, smart retries and account-updater events live behind one helper.

  • B2B

    B2B and ACH-heavy flows

    Ach payment software flows live in the same SDK as card — NACHA mandate evidence captured at sign-up, R-code retries handled by the platform, debit / credit through the same authorise endpoint.

  • PSP

    PSPs and ISVs reselling capacity

    Resellers integrate once and surface the SDK to their downstream merchants — branded if needed. The PSP keeps the relationship and pricing; the platform handles the per-provider plumbing.

  • Mobile

    Mobile payment software solutions

    Mobile payment software solutions on iOS and Android use the native SDKs that share the same authorisation engine as the server-side software. Apple Pay, Google Pay and regional wallets surface inside the SDK pay-sheet.

Platform features

Capabilities behind the payment software company surface

What the platform actually ships across the SDK family — the API contract, the back-end primitives, the operator surface and the security posture.

  • Unified payments API

    JSON-over-HTTPS REST surface with idempotency, predictable error model and OpenAPI specs.

  • Server SDKs

    Node, Python, PHP, Java, Go, .NET — each wrapping the REST surface with idiomatic helpers and types.

  • Mobile SDKs

    Native iOS (Swift) and Android (Kotlin) SDKs that share the same authorisation engine as server-side.

  • Webhook verification

    HMAC-signed events with per-language verification helpers; replay-safe with idempotency keys; SIEM-friendly.

  • Smart routing engine

    Per-transaction scoring on BIN, scheme, currency, country pair and risk — across the connected acquirer panel.

  • Cascade & retry

    Soft declines cascade to the next ranked acquirer inside the same authorisation; nothing leaks back to the buyer.

  • Split-payment gateway

    Splits applied at authorisation time per seller; per-seller settlement and reporting through the same reconciliation feed.

  • PCI DSS Level 1 vault

    Card data captures into vault; refunds, retries and recurring run on vault tokens.

  • ACH & SEPA primitives

    NACHA mandate evidence, R-code-aware retries, SEPA mandate management — same SDK surface as card.

  • Crypto via partner gateways

    Crypto rails inside the same SDK as fiat — stablecoins, majors, L2s via licensed partner gateways.

  • Operator portal

    Dashboard for authorisations, refunds, disputes and chargebacks across every connected provider and rail.

  • Sandbox parity

    Per-environment sandbox that mirrors production — routing, cascade, 3DS, refund and chargeback scenarios.

Trust & compliance

Compliance posture for secure payment software

Every authorisation runs through a single audited environment regardless of which SDK calls it. Merchants inherit posture rather than carrying separate certifications per provider or per surface.

PCI DSS Level 1
Annual on-site assessment plus quarterly ASV scans; sub-merchants inherit the posture across every SDK and rail.
Signed events
Webhook events HMAC-signed with rotation; replay-safe with idempotency keys.
Mobile-side security
iOS and Android SDKs use platform-native secure-storage primitives; no PAN in the app process.
SDK release process
SDK versions follow semver; security-relevant releases ship as patch versions with backport coverage for current major lines.
Data residency
Regional data-residency options for merchants under regulators that require it.
Licensed verticals only
Licensed gaming, regulated financial services and other compliance-bound verticals supported only where current operating licences exist. Grey and black-market verticals are out of scope regardless of integration shape.

Ready to integrate

One SDK family. Card, ACH, crypto and every method between.

A 30-minute SDK walkthrough covers the language SDK that fits your stack, the authorisation primitives relevant to your traffic, and a sandbox to test against before any commercial commitment.

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Frequently asked

Buyer questions about software payment processing on topropay

Questions buyers ask before committing — SDK ergonomics, language coverage, split payments, ACH, mobile, pricing.

  1. 01

    What does software payment processing mean on topropay?

    Software payment processing on topropay is the SDK-and-API surface a merchant integrates against — server-side libraries for every common language, mobile SDKs for iOS and Android, and a JSON-over-HTTPS REST API for anything else. The same software powers card, ACH, BNPL, regional APMs and crypto behind one contract.

  2. 02

    What software payment gateway primitives does the platform expose?

    Software payment gateway primitives include authorise, capture, refund, void, dispute response, webhook delivery, vault tokenisation, network-token issuance, 3DS / SCA orchestration, split-payment routing, sandbox parity and an operator portal API. Each is callable independently from any SDK.

  3. 03

    Which payment software solutions does topropay typically replace?

    Payment software solutions topropay typically replaces are single-provider gateway SDKs, per-method plug-ins (one library for card, another for BNPL, a third for crypto), and in-house integrations against one PSP's API. The replacement is incremental — topropay runs in parallel during the migration window.

  4. 04

    Are these software payment solutions suitable for small teams?

    Yes — software payment solutions on topropay are sized for small teams (one or two engineers can integrate the hosted-checkout path in hours) and for large teams that need full control of the surface via the SDK and OpenAPI. There's no platform retainer or per-seat licensing; pricing is per-authorisation.

  5. 05

    How does electronic payment software on topropay handle multiple rails?

    Electronic payment software on topropay treats every rail as a method on the same authorise endpoint. Cards, ACH, SEPA, iDEAL, PIX, BLIK, OXXO, PayID, BNPL and crypto all share the same SDK surface, the same vault, the same webhook event model and the same reconciliation feed. Per-rail metadata is exposed where relevant (NACHA R-codes, BCB end-to-end IDs, scheme tokens).

  6. 06

    What does e payment software look like in PHP specifically?

    E payment software in PHP is the PHP SDK installed via Composer. The SDK exposes Topropay\Client::authorise(), capture(), refund() and similar verbs; webhook signature verification has a per-event helper. The wire shape is identical to the other server-side SDKs, just idiomatic PHP types and class structure.

  7. 07

    What's the right framing for evaluating a payment software company at scale?

    A payment software company at scale should be evaluated on five axes: SDK ergonomics (does the team like working in it?), method coverage per market, routing / approval performance on the merchant's own traffic, reconciliation ergonomics for finance, and operational posture (uptime, support, sandbox parity). topropay scores well on all five by design — the orchestration model gives optionality across providers behind a stable SDK surface.

  8. 08

    How does split-payment gateway behaviour work in the SDK?

    Split-payment gateway behaviour is a body field on the authorise call: pass a splits-array with seller IDs, amounts and fee-allocation rules. The platform routes the funds per seller at settlement time; per-seller payouts and per-tenant reporting fall out of the same reconciliation feed. The merchant doesn't manage per-seller acquiring relationships individually.

  9. 09

    Is the secure payment software posture the same across SDKs and surfaces?

    Yes. Secure payment software posture — PCI DSS Level 1 vault, selective 3DS2 / SCA, signed webhooks, vault-token-only refund flows, replay-safe idempotency — is identical across every SDK, every surface (web / mobile / embedded) and every rail. The SDK changes who renders the code; the posture is platform-wide.

  10. 10

    What does the merchant software dashboard cover?

    Merchant software on topropay includes the operator dashboard (authorisations, refunds, disputes, chargebacks, reconciliation), a sandbox / live environment switch, API key management, webhook configuration, and per-merchant analytics on approval, cost and dispute outcomes. Larger merchants get role-based access control across the operator surface.

  11. 11

    How does ach payment software fit alongside card?

    Ach payment software lives in the same SDK as card. The merchant changes the method field (`method: ach`), provides NACHA mandate evidence at sign-up, and the platform handles the per-cycle debit, the R-code-aware retry calendar and the operator-side cancel flow. Same webhook event model as card.

  12. 12

    What credit card payment software primitives matter most for high-volume merchants?

    Credit card payment software for high-volume merchants leans on network tokens (cards persist across re-issuance), scheme account updaters (Visa VAU, Mastercard ABU), smart-retry decline-reason heuristics, selective 3DS / SCA orchestration, and per-BIN / per-scheme routing weights. topropay's SDK exposes all of these as configuration rather than per-merchant code.

  13. 13

    What mobile payment software covers in this stack?

    Mobile payment software covers the iOS and Android SDKs plus the same authorise endpoint they call. The SDK pay-sheet surfaces Apple Pay, Google Pay, regional wallets and a card form. Authorisations land in the same ledger as web authorisations; the merchant configures method availability per market from the dashboard.

  14. 14

    What mobile payment software solutions ship out of the box?

    Mobile payment software solutions on topropay ship as native SDKs (Swift for iOS, Kotlin for Android) with hosted pay-sheets, biometric-locked vault-token reuse, deep-link return URLs for redirect-based methods (iDEAL bank app, PIX bank app, BNPL providers), and signed-webhook delivery to the merchant back-end. The mobile SDK shares the same authorisation engine as the server SDK.

  15. 15

    Are online payment software solutions priced differently from desktop / server software?

    Online payment software solutions on topropay are priced per-authorisation on top of underlying provider economics — same pricing whether the authorisation came from a web checkout, a mobile pay-sheet or a server-to-server SDK call. There's no platform retainer or per-environment fee.

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