I build a Claude agent into your product.
Support, back-office, document processing: an agent that acts through your APIs, not a demo chatbot. In production in ~3 weeks, with a human in the loop. I've already built one for my own SaaS, Kryva: 40+ tools driven by Claude, in production since April 2026.
Diagnostic + prototype: 2 days · Development: ~3 weeks · Price locked before we start · EN / FR
See the offers ↓Offers
Three steps. Price locked before we start.
We validate on a real prototype before committing to development. Then the agent stays reliable over time.
01 — Validate
Diagnostic + prototype
2 days
€1,500 · $1,700
We scope the use case and I deliver a working agent prototype on your tools or test data.
- Scoping session: use case, data, risks
- Working prototype (text or voice)
- Priced production plan
Credited against step 2 if you go ahead. If the prototype doesn't convince you, we stop there.
02 — Build
Claude agent in production
~3 weeks
From €6,500 · $7,200
An agent that calls your tools and APIs, deployed and documented, with a human approving sensitive actions. Firm price set in the quote, after the diagnostic.
- Tools and APIs connected (CRM, back-office, database)
- Human approval on sensitive actions
- Logs, evals, error handling
- Code in your repo + 30-min handover
Launch price: €4,900 · $5,400 for the first 2 clients, in exchange for a testimonial and a publishable case study.
03 — Keep it running
Maintenance and improvement
Monthly
€300–500 / month
The agent stays reliable as models, APIs and your processes change. The amount depends on volumes.
- Monitoring and alerts
- Regular evals
- Model and API updates
- Small improvements included
No commitment, cancel any month.
VAT not applicable, article 293 B of the French General Tax Code. Invoiced in EUR (USD on request). Payment: 50% on signature, 50% on delivery. Something else — Vapi voice agent, Stripe Connect marketplace, Next.js / Supabase feature? Quoted on request.
Who it's for
Where I'm most useful.
SaaS and product teams
You want an agent that acts inside your product, not a demo chatbot. I integrate it into your stack, with your APIs and your guardrails.
- Support or back-office agent acting through your APIs
- Document extraction and processing
- Internal assistant wired to your tools
Agencies and dev shops
Your clients ask for AI and you don't have the team yet. I build under your brand, you keep the client relationship.
- White-label development under NDA
- Documentation for your team
- Monthly maintenance you can resell
Proof
What I built on my own.
One product in production, one in development. Kryva is where I learned what I sell: agents that take actions, with guardrails.
Kryva
Founder and sole developer · in production since April 2026
B2B SaaS for French construction trades, built solo.
Voice-driven AI quotes, Stripe payments, e-signature, KYB checks via Stripe, FEC export and Factur-X invoices. A Claude agent running 40+ tools with human approval on sensitive actions, a Stripe Connect Express integration with automated commissions, an enriched Apollo lead pipeline.
Krydor
Founder · in development
Network of RGE-certified trades with a MaPrimeRénov' grant simulator and AI pre-quotes.
Kryva's consumer channel: French renovation-grant simulator for homeowners, instant eligibility check, AI-priced pre-quote via Kryva's agent, job pooling across network trades.
Process
From first call to agent in production.
15 minutes to qualify
Calendly or the form. Three lines is enough: goal, current tools, deadline. I'll tell you honestly whether AI is the right answer.
Proposal within 24 hours
1-2 page quote: deliverables, schedule, price. Valid for 7 days.
Diagnostic + prototype (2 days)
We validate the use case on something real before committing to development.
Development (~3 weeks)
Daily written update, weekly demo. 50% on signature, 50% on delivery.
Delivery and follow-up
Code in your repo, documentation, 30-minute handover. Free fixes for 14 days, then monthly maintenance if you want it.
About
Sacha Praljak.
Freelance AI engineer, founder of Kryva (in production) and Krydor (in development). Coding since 2018, building with AI for the past 2 years.
I built Kryva solo, in production since April 2026: voice-driven AI quotes, Stripe payments, e-signature, FEC export and Factur-X invoices. At its core, a Claude agent running 40+ tools, with human approval on sensitive actions.
Sacha Praljak is the name I freelance under. My business is registered as Sacha Ruer EI (French sole proprietorship) — that's the name you'll see on LinkedIn, Malt and my invoices. Online payments show its registered trade name, Kryva.
EN / FR. Daily tools: Next.js 16, Supabase, Claude API, Vapi, Stripe Connect, Resend. Remote from the south of France (Paris time zone), working with clients in France and abroad.
FAQ
Frequently asked.
You're solo — what if you're unavailable?
The code lives in your repo from day one, with operating documentation, so someone on your team can take over without me.
What if the prototype doesn't convince us?
We stop there. You keep the prototype and the priced plan, with no commitment to the build.
When can you start?
Within one to two weeks for a diagnostic, depending on schedule. Development starts as soon as the quote is signed.
What moves the development price?
The number of tools and APIs to connect, volumes, and the level of human oversight. The price is fixed in the quote, after the diagnostic.
Do you work white-label for agencies?
Yes. You keep the client relationship; I build and document for your team. NDA available.
Which AI model do you use?
Claude (Anthropic) by default, for its reliability when calling tools. I document data flows for your GDPR records and put human approval on sensitive actions.
NDA / confidentiality?
Yes, I sign standard NDAs. For sensitive projects I offer a mutual NDA.
Payment terms?
Bank transfer or Stripe. 50% on signature, 50% on delivery. Above €5,000, three milestones are possible.
Business and invoicing?
Sacha Ruer EI (French sole proprietorship, micro-entreprise), SIREN 102 412 780. Compliant invoices, VAT not applicable, article 293 B of the French General Tax Code.
Clients outside France?
Yes: remote, contracts in English, invoicing in EUR or USD. Paris time zone, with overlap for EU and US East Coast.
Day rate?
I work on fixed prices by default. For a long time-and-materials engagement, let's talk: quoted on request.
Contact
Describe your use case.
Reply within one business day. For something faster, book 15 min on Calendly.
An agent in production, not a demo.
Fifteen minutes to find out whether your use case holds up.