A system that has become hard to evolve
Opaque architecture, technical debt, fragile dependencies: delivery slows down and each change becomes a calculated risk.
REELIANT · Digital Engineering Workshop
Engineering trust
Modernize. Build. Maintain. For the long run.
We modernize complex critical systems and embed digital trust from the architecture up. We step in when environments become hard to evolve, and we take responsibility for maintaining them in a trusted condition over time.
Top 1% EcoVadis Platinum
10 years Critical systems
40+ Regulated clients
100+ Projects delivered
Sectors & contexts
Where mastery becomes decisive
Stronger security or regulatory pressure
Identity, compliance, traceability: requirements are tightening. You need to integrate them without disrupting operations.
Need to transform without a brutal break
Modernizing legacy systems, launching new services: both must move forward without one putting the other at risk.
Core territory
Our 3 intervention pillars
Information System Modernization
Your legacy assets must evolve without disruption.
Your legacy systems keep the business running, but technical debt slows your deployments. We modernize them from the inside, through controlled iterations, without interrupting the service.
View service →New Services, AI & Cyber
Innovation must not mean losing control.
Business services and AI: we build them to integrate securely into your existing architecture.
View service →Maintenance in Trusted Condition (MCC)
"It works" is no longer enough.
We don't just maintain your applications: we guarantee control over them over time. When the regulatory or security landscape changes, you've already anticipated it.
View service →Engagement models
We adapt to your starting point
01
Quick diagnostic
Frame fast and decide right
In a few weeks, we map risks, clarify the trajectory, and propose an executable plan.
02
Dedicated team
Design and deliver with accountability
A senior team equipped to build, modernize, and integrate without disrupting your operations.
03
Piloted MCC
Sustain reliability over time
RUN, security, quality, and compliance steered with explicit criteria and readable governance.
OUR STANDARD
Digital trust by design
Protect
Identity
Strong authentication, entitlement management and access control.
Security
Prevention, detection and response: from code to infrastructure.
Engage
Compliance
Regulatory framework treated as an architectural constraint.
Traceability
Signatures, commitments and transactions: tracked, timestamped and legally binding.
Our AI conviction
AI as a lever. Mastery as a condition.
AI experiments are multiplying. But deploying it in production in regulated environments is another matter.
AI amplifies mastery: it doesn't replace it. On these environments, the foundation must be solid before accelerating.
LLMOps, agents, workflow automation: we design for production, with the same security and auditability requirements as the rest of the system.
Production references
Critical systems delivered and maintained over time
A few recent examples in production.
Finance & Automotive Credit
Digital Subscription Platform - BMW Financial Services France
Implementation of a fully digital subscription solution - in dealership and remotely - for BMW Financial Services France (ACPR-regulated credit institution) and its network of 295 points of sale (BMW, MINI, Motorrad). Fully paperless journey for both customers and advisors. Scope: identity & authentication, E-KYC, electronic signature, probative archiving. Live since 2020.
- More than 300 files processed per day
- E-KYC, KYB and Open Banking: enriched data for better decisions
- Full integration with BMW business tools
Identity & Qualified Signature
jesignexpert.com e-signature platform for the accounting profession - ECMA
Development and maintenance since 2018 of jesignexpert.com, an eIDAS-compliant electronic signature and sealing platform dedicated to the accounting profession. Covers three signature levels (simple, advanced with LCP nominal certificate, qualified via ANSSI-certified PVID) and supports multi-document, multi-signatory and multi-firm workflows.
- 5 million signatures and 1.6 million seals in 2025
- Electronic signatures from simple to advanced, with qualified certificate
- Integrated with 60 partners via dedicated APIs
- Interoperability with jedeclare.com and jefacture.com
- Gold medal Monde du Chiffre 2025 (7th consecutive year)
Energy & Professional Networks
New Extranet and consumer matchmaking platform - Les Professionnels du Gaz
Design and development of the new information system for habitA+, which manages the PG quality programme (Professionnels du Gaz) for 15+ years. Members include GRDF, ENGIE, EDF, Butagaz, Antargaz and emerging biomethane players.
- Support for 10,600 certified PG companies
- Business tools: maintenance certificates, Visa Qualité sheet, correspondence tracking, compliance audits and project monitoring
- Level assessment and integrated e-learning modules for professionals
- Commercial matching: offers published, ranked and tracked in real time
- Duty-of-care traceability: every intervention documented and legally enforceable
Water & Public Services
Online Web & Mobile Agency - Veolia Eau
Co-design, development and operation of Veolia Eau's online Web and Mobile agencies. The web online agency combines a showcase site and customer area, rolled out across local brands. Platform integrated with core business systems and continuously maintained.
- National app: 1M+ active users, rated 4.5/5 on app stores
- 15 local brand apps published and maintained on the stores
- Shared CMS (content management system): each brand publishes content locally or nationally
Our final validation test is simple: would we be proud to use this tool ourselves? If the answer is no, we don't ship it.
Our basecamp
Paris 9th, between Opéra and Saint-Lazare
Located in the heart of Paris, our workshop is a space for collaboration designed to stay close to our clients and foster teamwork across our teams.
10 rue Auber, 75009 Paris View on Google MapsJoin the Workshop
We build systems that last.
We recruit engineers who own the full lifecycle: design, development, production, operational maintenance.
- Growth through real-world experience, not slides
- Genuine architecture and security challenges, not simulations
- Every line of code written to last ten years
A demanding but rare environment: one where your work has a real and lasting impact.
Join us →
OUR INSIGHTS
Analyses & Perspectives
February 24, 2026
Data breaches: why MFA is now the sine qua non of trust.
Breaches keep coming, credentials keep circulating. In 2025, the right question is no longer how to protect your password: it is how to design authentication so that a stolen password has no operational consequence.
Read article →February 18, 2026
Open source and self-hosted AI models: real capabilities, real constraints
Llama, Mistral, Qwen, Gemma: open source models have considerably reduced the gap with frontier models. But 'free' does not mean no cost, and 'open source' does not mean no constraints. What you really need to know before choosing.
Read article →January 20, 2026
eIDAS 2 and the European e-wallet: what it concretely changes for your user journeys
The eIDAS 2 regulation and the European Digital Identity Wallet (EUDIW) will reshape identification and signing journeys. What CIOs need to anticipate right now.
Read article →Regain control of your system, and keep it
A first conversation lets us quickly assess your context, risk areas and the most relevant trajectory, without aggressive sales pitch.