IAI24
Pillar 04 · Custom SaaS

Your internal tool. Built for your business. Not for everyone else.

Stop stacking subscriptions to generic SaaS you only use 30% of. We design your internal app — your stack, your data, your brand, your logic. You own it. For good.

Free audit · 90 minutes · no commitment
app.iai24.fr/dashboard
MRR
48,2K€
+18%
ACTIVE USERS
1 247
+62
REVENUS · 12 SEMAINES
DERNIERS PAIEMENTS
Acme Corp
2 400 €
Globex
890 €
Initech
1 200 €
Why now

You're paying for tools that don't fit you.

Four reasons stacking generic SaaS always ends up costing more than a custom-built tool.

01 / 04
70% wasted

7 in 10 features go unused

You pay for Notion at $15 per user, and you use 30% of its capabilities. Same with HubSpot, Monday, Airtable. The rest just clutters your interface.

02 / 04
27 files

Your real stack is Excel

One file for invoicing, one for the CRM, one for project tracking, one for payroll. Twenty-seven in total. You know it. Your customers do too.

03 / 04
0% owned

Vendor lock-in

Your data lives at Notion, Airtable, HubSpot. The day they raise prices, shut down, or break your workflow, you rebuild from scratch. Zero control.

04 / 04
cost ×N

Costs balloon with the team

Every per-user license, every seat, every add-on multiplies. At 20 people, you pay €4,000/mo for 5 tools. Custom-built: a one-time investment, not a rent.

Capabilities

A modern app. Not a fragile MVP.

We build internal tools and proprietary products on the same stack as the best 2026 startups — Next.js, TypeScript, Supabase. Production-grade from day 1.

Production-grade 2026 stack

Next.js · TypeScript · Tailwind · Supabase · PostgreSQL. Same stack as Vercel, Linear, Cal.com. Maintainable, scalable, hireable.

STACKNext.js · TS · Tailwind · Supabase

Native AI, not bolted on

Claude, OpenAI, RAG embeddings woven into the core of the app. Copilot chat, semantic search, AI automations — native, not plug-ins.

AIClaude · GPT · RAG · agents

Auth, roles, multi-tenant

SSO, magic links, 2FA, granular roles, customer spaces, teams. All shipped on day 1, not in some future feature drop.

YTAdminall
ALMemberread · write
MKViewerread
AUTHSSO · 2FA · RBAC · audit log

Payments, invoices, subscriptions

If your app sells anything, we wire in Stripe: checkout, recurring subscriptions, invoices, dunning, financial dashboard.

PAYMENTSStripe · Lemonsqueezy · invoicing

Business integrations

REST APIs, webhooks, connectors to your existing tools. Slack, Stripe, your ERP, your databases — your app at the center.

GET/api/users200
{
"ok": true,
"count": 247
}
APIREST · webhooks · GraphQL

You own it

Source code is yours. Hosting in your name. No perpetual license, no dependency on us. We leave — your app stays.

yvan / mon-saas
main · 247 commits
private
Code sourcePas de licence
OWNERSHIPcode · data · self-hostable
Use cases

What do we actually build?

Internal business tool

CRM, ERP, project management, ops tracking. Designed around your exact process — not the other way around.

TODO4
DOING2
DONE8

White-label client portal

Dashboard where your customers see their deliverables, invoices, statuses. Under your brand, not some third-party vendor.

Acme Portal/clients
12
Factures
3
En cours
24K€
Total

Marketplace or platform

Connecting sellers and buyers, providers and clients. Multi-tenant, split payments, built-in moderation.

Studio Nova4.9Hot
Atelier 124.7
Pixel Lab4.5

B2B SaaS product

You have a rare expertise? We turn it into a recurring product, sellable to others. MRR guaranteed.

Free
0
/mois
Pro
49
/mois
Enterprise
199
/mois

Analytics dashboard

Your data unified into one app. Custom business KPIs, alerts, automated reports.

MRR12K +18%
Users847 +12%
Churn2.1% -0.3pt

Mobile field app

A PWA or native iOS/Android app for your field teams. Offline mode, sync, geolocation.

SYNC14:32
Online
Offline OK
GPS actif
Showcase

Six families of apps we build regularly.

Stylized mockups. Book the audit to see real apps shipped for our clients.

EdTechLMS

Online learning platform

CRMSales

Custom CRM for consulting firm

MarketplaceB2B

Provider-client marketplace

AnalyticsDashboard

Custom multi-source BI

Client portalWhite-label

Agency client portal

MobilePWA

Offline field-team app

Stack

The 2026 stack. Zero technical debt.

The bricks we assemble for your app. All battle-tested, all documented, all maintainable by a senior dev hired tomorrow.

BUILD0014weeks to launch
Our process

From your need to your app in production.

Step 1

Discovery & specs

We map your business, your processes, your data. Wireframes, data model, user journeys. Signed off together before any code.

Step 2

Build & design

2-week sprints, regular demos. You watch the app grow in real time. No surprise at launch.

Step 3

Tests & integrations

QA, security, performance. We connect your existing tools. A pilot team uses the app for real for 2 weeks.

Step 4

Launch & handover

Go-live on your infra. Training for your team. Full technical documentation. We leave — your app stays.

FAQ

The questions we get asked.

How long does it take to ship an app?
A robust internal app: 10 to 14 weeks. A production-testable MVP: 6 to 8 weeks. A complex platform (multi-tenant, payments, AI): 14 to 20 weeks. We scope precisely after the audit, based on your exact perimeter.
How much does it cost?
Pricing depends on functional scope, complexity, and development time. We scope it precisely after the free audit, with a fixed quote or sprint package. No standard package, no surprises.
Why not Bubble, Webflow, Glide, or no-code?
No-code is great for validating an idea in 2 weeks. For a tool used in production by 20 people for 5 years, you hit the ceiling fast: performance, customization, exports, editor lock-in. A coded app scales linearly and stays your asset. It's a different level of commitment.
What about maintenance? Will you be around in 3 years?
We offer a monthly maintenance contract (fixes, updates, evolutions). But you're not dependent: your code is documented, hosted in your name, hireable by any senior TypeScript dev. If we disappear, your app survives. That's the price of an honest custom build.
Do you actually code, or just template?
We code. GitHub repo in your name from week 1, daily commits, peer code review. We use proven open-source foundations (Next.js, Supabase, shadcn/ui) — not to save time, but to guarantee maintainability. The business logic of your app is coded for you, line by line.
Who hosts the app, who owns the data?
Your app is hosted in your name (Vercel, AWS, OVH, or self-host). Your data is in your PostgreSQL database, in your name. GDPR-compliant by default. You can export or migrate anytime, without asking us.
What about AI in all this?
AI is built in from day 1, not bolted on. Copilot chat on your data, semantic search, content generation, AI automations: all native. We use Claude and OpenAI depending on the case, with an abstraction layer so we can switch if a better model ships.
Do you work as a team or solo?
On every project: a product designer, a lead full-stack developer, a back-end developer, and an AI supervisor. On complex projects, we add a front-end developer and a DevOps. You get one point of contact, with a team of 3 to 5 people behind.
Where to start

Not sure which solution fits?

We always kick things off with a free 90-minute audit. We dig into your business, surface the highest-leverage AI opportunities, and hand you a concrete action plan. No commitment. Even if we don't end up working together.

90 minutesno commitmentreply within 24h