I'm a CTO and software architect in Paris. I co-founded Togethrust, where I own the architecture and run engineering. Alongside it I work as a fractional CTO for fintechs and regulated companies that need senior technical leadership without hiring for it full time. Seventeen years in, most of that time has been spent on systems where being wrong is expensive: trading and back-office platforms, national infrastructure, and payments.
Togethrust — Co-founder & CTO, since October 2025.
Togethrust takes the tontine — the rotating savings pool that families and colleagues have run on WhatsApp threads and spreadsheets for generations — and makes it a regulated product. Members join a pool, contribute on a schedule, and receive the pot in turn, with identity verification, traced transfers, and loan contracts that hold up in front of a bank.
It's registered with ORIAS as an Intermédiaire en Financement Participatif (n°24006639) and supervised by the Banque de France. We're incubated at HEC Paris, at Station F.
The regulation is what shapes the data model. A pool isn't a pot of money we hold — it's a set of bilateral loans between members, which is what the IFP registration requires and what makes the contracts enforceable. Members are onboarded with KYC under the anti-money-laundering obligations of article L.561-2 of the Code monétaire et financier. Contributions run weekly or monthly by card or SEPA direct debit, and payout order is drawn by lot or agreed by the group.
The ledger is where the real work is. Because a pool is loans rather than a balance, every contribution and payout has to resolve into per-member positions, and those positions have to reconcile against settlement events that arrive late, out of order, or more than once. A discrepancy there isn't a display bug — it's a wrong answer to who owes whom, and that answer is a contract.
I work with seed-to-Series A fintechs, banks, and regulated industries — the places where getting architecture wrong isn't just expensive, it's existential. I embed with the team and make decisions rather than hand over a deck.
| Engagement | Length | What it covers |
|---|---|---|
| Fractional CTO | 3–6 months | Tech strategy, architecture decisions, hiring, team structure, regulatory guidance |
| Tech audit & coaching | 2 weeks–3 months | Architecture review, DORA metrics, CI/CD, developer experience, tech debt roadmap |
| Tech due diligence | 2–3 weeks | Architecture, team and process review, scalability and risk assessment for VCs and M&A |
Recent results: cut delivery cycle time by 40% through CI/CD automation, reduced cloud spend by 35% via migration and rightsizing, and — at a MENA mobility platform, leading four teams through a transition — cut operations tickets by 20% and technical debt by 30%. I've mentored 100+ developers across five countries.
Details and case studies at ksouf.com. To talk about an engagement, book a call.
| Languages | TypeScript, Java |
| Backend | NestJS, MongoDB |
| Frontend | Next.js, React Native (Expo) |
| Platform | GCP (Cloud Run), Terraform, GitHub Actions |
| Observability | OpenTelemetry, Grafana, Sentry |
Practices matter more than the list: Domain-Driven Design and hexagonal architecture, held honest by TDD and BDD, trunk-based development, and DORA metrics as the feedback loop. Agent-assisted development with Claude Code is part of the daily loop now, not an experiment. I still write code.
I co-founded Socrates Canada (2019) and co-organized the Software Crafters meetups in Montreal (2019–2021) and Romandie, Switzerland (2021–2024).
Selected podcast appearances:
- The challenges of Fractional CTOs — Tech Lead Corner #14 (French)
- Building Self-Sustaining Systems in Tech Organizations — Better Tech Leadership #90
- Track Down Dead Code and Delete It — Maintainable
- Interview micro-services — Les Cast Codeurs #235 (French)
- The Value of Creating Value — DevJourney #90
I ran a full-day workshop and gave a talk on naming at DDD Europe 2022, and spoke on microservices at Alpes Craft 2023. The full list is at ksouf.com/talks.html.
- fintech-architecture-patterns — Payment orchestration, event-sourced compliance, multi-tenant banking, and audit trails, each with the anti-pattern I've watched teams ship instead.
- fintech-cto-checklist — Pre-seed to Series A technical readiness, plus ADR and incident post-mortem templates. What I'd want on day one of a diligence.
- dddeu22-let-me-be-free-typescript — The codebase from my DDD Europe 2022 workshop — hands-on Domain-Driven Design in TypeScript, modelling an interview-scheduling domain.
- presentations — Conference decks on DDD, architecture, and technical leadership (archive, last updated 2022).
- LinkedIn — khaled-souf-cto
- Website — ksouf.com
- Email — khaled.souf@gmail.com
- Book a call — cal.com/khaled-souf-wthqet
For fractional CTO work, technical due diligence, or an architecture review, email me or book directly. I reply to specifics faster than to introductions.