Payment and integration architecture for teams where a failed transaction is a real incident
I design and repair the systems banks, payment companies, and regulated platforms depend on — ISO 20022 and SWIFT messaging flows, MQ and event-driven integration layers, and the reconciliation and audit paths that have to hold when things go wrong.
Ten years across banking, telecom, and cloud platforms, including four as a CTO and architecture lead. I keep client detail off this site — see below.
Built for teams where architecture mistakes are expensive.
I work best with founders, CTOs, engineering leaders, and product teams who are building systems where reliability, auditability, integrations, security, and delivery speed matter.
Fintech & regulated products
Banks, payment processors, remittance products, lending platforms, and banking vendors — where correctness is auditable, failure is expensive, and the integration surface is the hardest part of the system.
Teams integrating with banks and payment rails
Product teams about to connect to a bank, a card scheme, a core banking platform, or a payment rail for the first time — and who want the design reviewed before six months of engineering goes into it.
When teams call me.
- We're getting duplicate settlements and nobody can reproduce it
- Our integration layer has become the thing everyone is afraid to touch
- We're going into a bank integration and don't know what we don't know
- Reconciliation breaks at month-end and we fix it by hand every time
- An auditor wants proof of what happened to a specific transaction, and we can't produce it
- We're about to commit six months of engineering to a design nobody senior has reviewed
- Our AI pilot works, but we can't put it anywhere near regulated data as it stands
How I think about payment systems.
Four positions I hold, so you can decide whether we'd agree before you pay me anything.
- 01
Exactly-once delivery doesn't exist. Design for idempotency instead.
Every broker that advertises exactly-once semantics is describing a guarantee that holds inside its own boundary and dissolves the moment your handler talks to a database, an external rail, or a second service. The systems that survive are the ones where processing the same instruction twice is provably harmless. That is a design property, not a configuration flag, and it has to be decided early because retrofitting it means touching every consumer you have.
- 02
Reconciliation is a property of your message design, not a batch job you add later.
Teams routinely design the happy path first and treat reconciliation as reporting. Then month-end arrives, the numbers don't agree, and someone starts fixing it by hand. If your messages don't carry enough identity and causality to reconstruct a transaction's full history from either side of an integration, no reconciliation process downstream can recover what the design threw away.
- 03
The integration boundary is where payment systems fail, not the core.
Core logic gets attention, review, and tests. The seams between systems get a mapping document and an assumption that the counterparty behaves. Almost every serious incident I've been called into lived at a boundary — a field silently truncated in translation, an acknowledgment that never arrived, a partner whose retry behaviour nobody had characterised under load.
- 04
An audit trail is a product requirement, not a logging concern.
"Can you show me exactly what happened to this transaction, and prove nothing else touched it" is a question that arrives from a regulator, a partner bank, or a customer's lawyer — usually at short notice. If the answer depends on correlating four log streams by timestamp, you don't have an audit trail. Deciding this after the fact is expensive; deciding it during design costs almost nothing.
Consulting services.
Payment & Integration Architecture Review
Two weeks · Fixed price $8,500
A structured teardown of your payment or integration layer, delivered as a written assessment with a prioritised remediation roadmap your team can execute without me.
Things I go looking for:
- Message idempotency under MQ redelivery — what happens when the same payment instruction arrives twice
- Reconciliation gaps when acknowledgments arrive out of order, or never arrive
- In-flight transaction handling during failover and deployment
- Poison messages and retry storms taking down a consumer under load
- Field-level data loss in ISO 20022 mapping, and where it surfaces months later in compliance reporting
- Audit trail completeness — whether you can actually reconstruct the life of a given transaction
- Places where exactly-once delivery is assumed in the design but not guaranteed by the infrastructure
You get: a written assessment, an annotated architecture and data-flow map, a ranked risk register with business impact, and a remediation roadmap — plus a working session with your engineering team to walk through it.
If, at the end of the first week, you don't think the review will be worth what you're paying, say so and we stop — you pay half and keep everything produced so far.
What the deliverable looks like
Every review produces the same document structure, typically 25–40 pages depending on system complexity:
- 01Executive summary — what I found, what it puts at risk, what it would cost you, written for someone who won't read the rest
- 02System and data-flow map — annotated, showing message paths, boundaries, ownership, and where state actually lives
- 03Failure-mode analysis — each identified weakness with a reproduction path, blast radius, and likelihood
- 04Ranked risk register — ordered by business impact rather than technical severity, with the two lists compared where they diverge
- 05Remediation roadmap — sequenced, with effort estimates, and marked for what your team can do without me
- 06Decisions you should make and won't like — the ones with no clean answer, laid out with the tradeoff stated honestly
Plus a recorded working session with your engineering team to walk through it and argue with it.
Implementation Sprint
Three to four weeks · From $14,000
Scoped delivery against a defined outcome — an integration built, a messaging layer rebuilt, an AI workflow put into a regulated environment with audit logs, approval gates, and data boundaries intact.
Typical scopes:
- ISO 20022 or SWIFT messaging flow designed and implemented end to end
- Event-driven integration layer replacing brittle point-to-point connections
- Reconciliation and exception-handling design for a payment flow
- Retrieval and tool-use AI workflow with guardrails, human approval, and evaluation, deployed where regulated data lives
Fractional Architecture Partner
Ongoing · From $6,000/month
Senior architecture judgment on retainer, for founders and engineering leaders who need it continuously but can't justify a full-time hire. Roughly four to six days a month.
What that covers:
- Weekly architecture and design review sessions
- Decision support on vendors, platforms, and build-versus-buy
- Delivery oversight and technical risk escalation
- Direct support to your engineering leads
Most engagements start with the Architecture Review. It stands alone as a deliverable, and it's the fastest way for both of us to find out whether something longer makes sense. Email me and we'll scope it in a couple of messages.
Why there are no logos on this page.
Most of my work has been inside banks, regulated platforms, and companies where the architecture is not something the client wants discussed publicly. I don't publish client names, logos, or case studies, and I don't reuse your material as marketing either. If you want to verify my background before we talk, my employment history is on LinkedIn.
What I'll give you instead is a sample of the actual deliverable, above, and a first conversation specific enough that you can judge the work directly.
How engagements work.
- 01
Email exchange
Tell me what the system is, what's going wrong, and what failure would cost. Two or three messages is usually enough to establish whether there's a fit and to scope a review.
- 02
Paid review or focused sprint
We start with a focused architecture review, prototype, or implementation sprint — scoped around a clear technical and business outcome.
- 03
Implementation or advisory
If there is a fit, I continue as an implementation partner, fractional architect, or delivery advisor.
Technical depth.
The architecture leads, not the tooling — but for teams who want to know the range behind it, here's where I go deep. I work across languages and stacks; the list below is what I've shipped in production, not a preference.
- Enterprise & fintech
- ISO 20022-style messagingBPM / BAWTOGAFBABOKITILDomain-driven design
- Blockchain & distributed ledger
- Hyperledger FabricEthereumRipple / XRP LedgerChaincode & smart contractsPermissioned network designConsensus & finality models
- Backend & integration
- JavaJ2EENestJSNode.jsGraphQLRESTMQEvent-driven architecture
- Cloud & platform
- AzureKubernetesDockerHelmPulumiCI/CDObservability
- AI systems
- RAGLLM workflowsPrompt-injection awarenessEvaluationAudit logsGuardrailsHuman approval
- Data & identity
- PostgreSQLMySQLDB2RedisKeycloakOAuth / OIDC
- Product & mobile
- ReactReact NativeExpoProduct strategyUX-focused delivery
Before you email.
- Why won't you tell me who you've worked with?
- Because the clients whose systems I've worked on didn't hire me to talk about them. Confidentiality is part of what you're buying, and a consultant who advertises the last engagement will advertise yours. My employment history is public on LinkedIn if you want to verify the background.
- Why fixed price rather than a day rate?
- Because a day rate makes it in my interest to take longer, and you shouldn't have to manage that. The scope is defined up front, the price doesn't move, and if the work runs long that's mine to absorb.
- Can you work alongside our existing team?
- That's the normal case. I'm not there to replace anyone's judgment — I'm there to review the design, name what's fragile, and hand your engineers something they can act on. Most of the value shows up in the working session, when your team pushes back.
- What if we need implementation help afterwards?
- The review stands alone and is written so your team can execute it without me. If you'd rather I stayed on, that's an Implementation Sprint or a Fractional engagement, and the review fee comes off the first invoice.
- Will you sign an NDA?
- Yes, before any system detail changes hands. Send yours, or I'll send a short mutual one.
- Where are you, and how do you work?
- Cairo, working UK and US-East overlapping hours. Reviews run remotely by default. I travel for onsite discovery where the system or the room makes it necessary.
A senior partner, not a vendor.
I'm Muhammad Salah Masoud, an architecture lead and former CTO working with teams across US and European timezones. I've spent 10 years building and leading cloud-native platforms, enterprise integrations, banking and payments systems, mobile products, and AI-driven workflows.
My strength is connecting product goals with serious engineering constraints: reliability, security, integration complexity, cloud delivery, and the messy reality of shipping software in business environments.
Based in Cairo. I work UK and US-East overlapping hours, and travel for onsite discovery when an engagement calls for it.
Off the keyboard
An avid reader of technology and science, I keep audio engineering and DSP as a serious off-hours craft — and play more electric guitar than I should probably admit.
Tell me what's breaking.
Email is the way in. I read everything and reply to anything with a real system behind it.
Helpful to include: what you're building, what's blocked or unreliable, what regulatory constraints you're under, and your timeline. Rough is fine — I'd rather have three honest sentences than a polished brief.