Accueil/Expertises/Applications & Sites/Applications sur mesure
Expertise · Custom Applications

Your applications, designed, tailor-made

From scoping to launch. Modern stack (Next.js, TypeScript, Supabase, PostgreSQL) with integrated AI when it delivers measurable value.

app.sitex.com / commandes
v2.4.1
Commandes · semaine 21
2 384
+12% vs S20
IDClientStatutMontant
#10428Loiret SAEn cours1 240 €
#10427BellmanLivré 860 €
#10426CabaiaLivré2 110 €
#10425Art ExploraEn attente 540 €
01 — Why us

One team.
From scoping to delivery.

Three concrete commitments that shape how we deliver, from the first workshop to production deployment.

01

One team, from the first workshop to support

Scoping, design, development, deployment. The developer who speaks with your team during scoping is the one who writes the code.

02

Production-grade code, not a disguised AI prototype

AI speeds up our prototypes, but what goes into production is reviewed, tested, monitored, and maintainable by your teams.

03

Modern stack, technical debt under control

Next.js, strict TypeScript, PostgreSQL, automated tests, human and end-to-end testing.

02 — Areas of Expertise

Four types of applications.
A dedicated page for each area.

Four formats we regularly design and deliver. Click to see our approaches, client cases, and the tailored method for each.

Looking for an editorial site or a multi-country CMS? View Websites & CMS.

05 — Other Cases

Have another application idea? Let’s talk! A single call is enough to assess the project and estimate next steps.

Book a meeting
03 — Tech Stack

A modern stack,
and scalable.

We adapt our stack to your context (sovereignty, GDPR, existing internal teams, SI integrations).

01

Front

Next.jsReactTypeScript
02

Back / Data

SupabasePostgreSQLDirectusn8n
03

AI / Agents

MistralOpenAIClaudeMCPLangGraph
04

Auth (SSO)

Supabase AuthAuth0KeycloakSAML
05

Tests

VitestPlaywright
06

Ops / Hosting

OVHScalewayDockerVercel
07

Monitoring

SentryPostHog
08

CI / CD

GitHub Actions
Each stack choice is discussed during scoping to meet your needs—never imposed by default.
04 — Client Case · SiteX

From Airtable to a custom application.

Gradual migration to Next.js + Supabase, with coexistence of the old system until full switch. Zero business disruption.

Read the case study
SaaS · Security2024 — 2026 · 24 months

Sitex

Business application for planning event security services, with on-site tracking and real-time incident reporting.

-40%planning time
3xfaster to report an incident
24/7on-site reporting via QR code
Next.jsSupabase
05 — Methodology

A project

No handoffs between scoping, build, and run. The same engineers support you from the first workshop to maintenance, so knowledge isn’t lost along the way.

01Scoping1 to 3 weeks

Spec, plan, estimate.

Business workshop, use-case mapping, constraints (IT systems, GDPR, security), quantified success criteria. Deliverable: functional spec + technical plan + firm estimate.

02Design produit2 à 4 semaines

Parcours validés.

Wireframes, parcours, design system, maquettes. Une validation complète avant écriture du code.

03Build itératif2 à 6 mois

Sprints de 2 semaines.

Démo à chaque sprint. Vos équipes IT impliquées dès le sprint 1 — revues de code, pair programming si demandé.

04Mise en prod1 à 2 semaines

Bascule sécurisée.

Tests de charge, audit sécurité, plan de bascule, formation des équipes. Pas de Go Live sans critères de qualité mesurés.

05Run & évolutionsContinu

Maintenance ou transfert.

Maintenance corrective, évolutions, transfert progressif aux équipes internes si souhaité. Notre intérêt n'est pas de devenir indispensable à votre run.

06 — FAQ

Frequently asked questions

The most common questions we get during scoping. If yours isn’t here, reach out!

Default stack: Next.js + Supabase + TypeScript. We adapt if you have an existing system (Python, Go, Java) or specific infrastructure constraints. The stack is chosen during scoping, based on your real context.

No. AI is one tool among many. We integrate it when it delivers a measurable gain: internal assistant, RAG, automation agent. Not to tick a marketing box.

Yes, if desired. Co-building from scoping, code reviews, documentation, training. Knowledge transfer is included in the scope.

Yes — on OVH, Scaleway, or self-hosted. Depending on data sensitivity (healthcare, defense, finance), we adapt the architecture.

Optional maintenance contract (SLA, on-call, enhancements) or full handover to your teams with documentation and training. No technical lock-in — our interest isn't to become indispensable to your run.

Yes — it's one of our core activities. Independent audit in 1 to 2 weeks, diagnosis, and building a takeover plan.
Get started

An idea, a business need, or an existing project to take over?

Contact details
contact@agence-scroll.com
+33 6 48 03 90 27
20 Rue des Taillandiers
75011 Paris
Reply within 24 business hours.