werk 04 · software engineering

Software.

Architecture, integration and engineering quality — the target architecture and the delivery organization that ships to it without surrendering availability.

FamilyBuildCarried byInterimProven lines5 / 7Detailed mandates8SectorsFinance & Insurance, Health & Life Sciences, Industry & Mobility, Media & Entertainment, Retail & Luxury

Werk 04 — who carries it

arms and mandates

Architecture is only real once it ships. This werk holds the target architecture, the integration surface and the engineering organization, and is measured on what runs rather than on what was specified.

The offer

what is bought, and in what shape

A target architecture that is actually built — services, APIs and front-end platforms delivered by an engineering organisation with quality gates it respects, without surrendering availability on the way.

Target architecture and integration blueprint

Domain decomposition, service boundaries, event contracts and the integration layer between the estate and its partners.

API and headless commerce platform

API strategy and gateway, composable front-end platform, and the migration path off coupled monolithic front ends.

Reliability and performance programme

SLOs, error budgets, load and resilience testing, and the incident practice that keeps the SLA honest.

Engineering quality and developer experience

Test strategy, CI/CD pipelines, code ownership and the metrics that make delivery throughput visible.

Architecture review3 to 6 weeks

Architecture assessment, target design, risk and cost impact.

AdvisoryFractional chief architect

Design authority, technical arbitration, standards owned.

Interim seat6 to 18 months, CTO

Engineering organisation and delivery to the target architecture.

MACHEvent-driven architectureKubernetesAPI gatewaysContract testing

State of the proof

counted from the ledger below
7sub-capabilities
5proven · a published case carries a sourced figure
2held · carried by a named operator, no case published
0declared · in scope, no published proof today

Experiences that prove it

8 detailed mandates
PMUMedia & EntertainmentA mainframe-to-AWS modernization that cut total cost of ownership by 87% while holding 99.995% uptime on the replatformed betting applications.Proves: Enterprise and software architecture · Reliability and performanceSociété GénéraleFinance & InsuranceA BU MassMarketing cloud migration off owned datacenters onto AWS that cut total cost of ownership by 37%.Proves: Enterprise and software architecture · APIs and integrationDerichebourg EnvironnementIndustry & MobilityAn end-of-life-vehicle site rebuilt from a legacy monolith into a microservices platform, lifting the conversion rate by 18%.Proves: Microservices and event-driven designCarrefourRetail & LuxuryThe #OneCarrefour V1 and V2 e-commerce replatforming, run as CTO of a dedicated 120-person Publicis delivery agency.Proves: Front-end platforms and headless commerceLegrandIndustry & MobilityA redesign of the legrand.fr corporate and e-commerce platform onto a headless Drupal front office with an Adyen payment gateway, run with a 30-person team.Proves: Front-end platforms and headless commerceSateliaHealth & Life SciencesA six-month transition CPTO mandate at a cardiovascular telemonitoring medtech, completed in July 2026, moving 15 people from a monolith to microservices for EU market entry.Proves: Microservices and event-driven designLVMHRetail & LuxuryA multi-brand e-commerce replatforming across LVMH maisons, rebuilding the online flagships of Louis Vuitton and Dior.Proves: Front-end platforms and headless commerceBNP Paribas CetelemFinance & InsuranceA C/C++ to Java Spring modernization with PayPal integration for BNP Paribas Personal Finance (Cetelem), run as CTO at Tata Consultancy Services.Proves: APIs and integration

Sub-capabilities and evidence

7 lines, each with its state
Enterprise and software architectureprovenPMUSociété Générale
Microservices and event-driven designprovenDerichebourg EnvironnementSatelia
APIs and integrationprovenSociété GénéraleBNP Paribas Cetelem
Front-end platforms and headless commerceprovenLegrandLVMHCarrefour
Reliability and performanceprovenPMU
Developer experienceheldSoftware and digital factory built and industrialized at AXA group level.
Quality and testingheldCarried inside the AXA factory mandate; no isolated case published.

Publishable figures

named, sourced, attributable
99.995%SLA held through a mainframe exitErwan Deschamps · Group Chief Enterprise & Software Architect, PMU (2013-15)
+18%Conversion after monolith to microservicesErwan Deschamps · local-entity CTO, TCS for Derichebourg Environnement
250Engineers across 5 business unitsErwan Deschamps · Group CTO Digital & Big Data, AXA (2017-18)

Questions

answered, in the open
How is a replatforming kept safe?
In stages, with availability validated at each cut. The PMU betting platform left the mainframe for AWS while holding a 99.995% target, which is a delivery outcome rather than a slide. A single switchover would have been faster to plan and impossible to defend.
What is the architectural bias?
Composable over monolithic, event-driven where state is contended, headless where the front end changes faster than the core. Derichebourg's end-of-life-vehicle platform moved off a monolith onto microservices and conversion rose 18%. legrand.fr was rebuilt on a headless Drupal front office with an Adyen omnichannel payment gateway, run with 30 FTE.
Does the collective write code?
It engineers and ships. The mandate is accountable to a system running in production, not to an architecture document handed to a party that did not help shape it.
At what scale has this been held?
250 engineers across five business units at AXA, 120 FTE on the Carrefour replatforming, 30 on Legrand, 15 reorganized into autonomous squads at Satelia. The mandate covers the organization that ships, not only the design it ships to.

Related werks

same family, shared proof
Discuss a software mandateHow Interim runs itAll eleven werks