Our story
Cestra started as Achile's solo freelance activity while studying engineering, under the French sole-proprietor status (EI). As projects grew, he brought in his classmates Théodore and Killian — also engineering students, each with their own specialty — to join larger missions, each invoicing through their own freelance structure.
Today, "Cestra Technologies" is the trade name we use to present the whole. When a project needs it, several freelancers work together: one lead handles the relationship, the others bring their specialty. When one is enough, the engagement stays 1-to-1, with no middleman.
Legal status
How it's actually structured
Not a company
"Cestra Technologies" is a collective trade name. The registered entity is Achile Coskun — EI (French sole proprietor, SIRET 933 882 276 00019).
Independent freelancers
Each member operates under their own structure. You contract directly with the freelancer who signs — no hidden subcontracting layer.
Engineering students
We are currently in engineering school: engineers by skill, not yet certified. We never claim the protected "chartered engineer" title.
Team
The people behind the tech
Three engineering students working as freelancers, each with their own specialty. No agency, no middleman — you work directly with the people doing the work.
Theodore Letard
Freelance · Web & SaaS
Builds systems that stay maintainable long after delivery.
Achile Coskun
Founder · AI & Data
Control over complexity
Killian Hubault
Freelance · Cybersecurity & Network
Paranoid about security and compliance.
How we work
Three things that don't change
Clear contracts
You deal with a named freelancer, accountable for the deliverable. Each member invoices under their own legal structure.
Team on demand
Depending on scope we assemble a small team (web, AI, cyber, brand) or keep it solo. No agency markup sitting in between.
Traceable documentation
Every project ships with proper documentation — architecture, decisions, technical rationale — so your teams can take over and evolve it.
Working with us
Tell us about your project — we'll tell you who'll handle it.
Depending on what you need, we put you in front of one freelancer or a small team assembled for the mission. Quote and timeline within 48h.