Payment processing gateway software
Payment processing gateway software,
card and crypto in one ledger.
TrustChange engineers bespoke payment processing gateway software for PSPs, EMIs and neobanks across the EU. One team owns the router, the ledger, the risk rules and the payout path. You get a gateway you can run, reconcile and prove.
- EU-based engineers
- PSD2-aware delivery
- PCI DSS readiness
Rails
Rails our payment processing gateway software wires in
Every market wants a different way to pay. The router hides that from your product team. One integration, many methods.
Moving between fiat and digital assets? See on- and off-ramp integration, matching-venue work on crypto exchange development, and key handling on wallet and custody engineering.
| Rail | What we build |
|---|---|
| Card acquiring | Tokenised card flow with 3-D Secure step-upVault, retries and refunds sit behind one API. |
| SEPA & SEPA Instant | Bank file and API rails with payout batchingMandates, returns and R-messages handled in code. |
| Open banking | PIS and AIS links under PSD2 consent rulesConsent state is stored, not guessed. |
| Crypto pay-in | On-chain deposits with confirmation policyQuotes lock a rate for a set window. |
| Payouts | Fiat and on-chain withdrawal with approvalsEvery payout carries a signed approval trail. |
| Local methods | Wallet and bank redirect methods per marketNew methods plug into the same router. |
Scope
Four systems inside every payment processing gateway we build
A gateway is not one service. It is four subsystems that must agree on every cent. We build them together, on one plan, with one team accountable end to end.
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01
Router & orchestration
One router picks the cheapest working path. It fails over when a provider slows down or drops.
- Rule-based routing
- Provider failover
- Retry windows
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02
Ledger & reconciliation
A double-entry ledger holds every movement. Provider files reconcile against it each day.
- Double-entry core
- Daily file match
- Break queue
-
03
Risk & fraud controls
Rules and velocity checks run before capture. Analysts get a queue they can actually work.
- Velocity rules
- Sanctions screening
- Case review
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04
Merchant tooling
Onboarding, dashboards and API keys ship with the gateway. Support stops living in your inbox.
- KYB onboarding
- Merchant portal
- Webhook logs
Money path
From tap to settled funds
Payments fail in the gaps between steps. So we design the whole path, then make each hand-off replayable.
- 01
Authorise
Seconds
The router picks a path. Risk rules run before the charge is taken.
- 02
Capture
Same day
Funds are captured and written to the ledger as a double entry.
- 03
Reconcile
T+1
Provider files are matched line by line. Breaks land in a queue.
- 04
Settle & report
T+1 to T+2
Merchants are paid out. Reports go to finance and your auditor.
Engagement
Four ways to buy the work
Scope changes as you learn. The commercial model should move with it.
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Fixed-scope build
A defined gateway, a fixed price, a dated plan. Best when scope is settled.
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Dedicated team
A standing squad with a lead. Best for long roadmaps and steady releases.
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Staff augmentation
Senior engineers inside your team. Best when you own the plan already.
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CTO advisory
Architecture and hiring guidance. Best before you commit to a build.
Questions
FAQ: payment processing gateway software
Six answers payment teams ask first — scope, controls, ownership and audit. Bring the rest to the call.
Related work sits on our fintech infrastructure page and in how we deliver.
What does payment processing gateway software cover in your builds?
The four subsystems on this page: a router that picks and fails over between providers, a double-entry ledger that records every movement, risk and screening controls that run before capture, and merchant tooling for onboarding, keys and webhooks. All four ship as one gateway behind one API, in your own repositories.
Do you replace our current provider or wrap it?
Both patterns are common. Most engagements start by wrapping current providers in the router so nothing in production changes on day one, then add or swap rails as the roadmap allows. That keeps working revenue live while the new payment processing gateway software takes shape underneath.
Can one gateway take cards and crypto in the same ledger?
Yes. Card, SEPA, open banking and on-chain legs all write into the same double-entry ledger, so finance reads one report and reconciles against one source of truth. Crypto legs carry Travel Rule data where required and reuse the same risk-screening pipeline as fiat.
How do you handle PSD2, SCA and PCI DSS scope?
SCA exemption and step-up logic is engineered into the checkout and payout flow — your advisers set the policy, we ship the code and the evidence. Card data is tokenised so PCI DSS scope stays small, with hosted fields and vaults keeping raw PANs out of your systems entirely.
Who owns the gateway, the code and the data at the end?
You do. TrustChange builds bespoke, client-owned systems: no white-label licence, no per-seat fee and no lock-in. The code lives in your repositories under your process, the data stays in the regions you choose, and contracts assign IP to you from day one.
What audit evidence do we get from the gateway?
Every transaction leaves a signed trail: routing decision, risk verdict, ledger entries, reconciliation match and payout approval. Reports are exportable for finance and for external auditors, and access to production data is logged against a named identity rather than a shared service account.
Book a discovery call on your payment processing gateway software
Bring a rough money-flow, the rails you already run and the ones you need next. We come back with an architecture view, a risk list and a costed plan. No demo theatre.