I ship in prod what most teams take 18 months to launch.
Founder of Kryva.fr (B2B SaaS in production, shipped solo in 4 months). Available full-time for short or long engagements on Claude tool-use agents, Vapi voice agents, Stripe Connect, Next.js 16. Remote — EU + US clients.
Real Claude agent loop running daily on kryva.fr
My latest production project
Kryva.fr
B2B SaaS for French construction trades — AI voice quoting, Stripe payments, e-signature, accounting, Claude tool-use agents, Vapi voice agents. 0 → prod in 4 months.
By the numbers
No promises. Artifacts.
Everything below runs in production on kryva.fr for the past 4 months.
From zero to SaaS in production (kryva.fr)
Claude tools shipped in production
B2B leads enriched automatically
Worldwide — EU + US East Coast overlap
Fluent EN — work in either language
Now — full-time engagements possible
What I do
The stuff that’s hard to find elsewhere.
No demos — real code in production. Bilingual (FR/EN) — work seamlessly with US/UK/EU teams.
Claude tool-use agents in production
40+ tools shipped on Kryva. Human-in-the-loop gates, streaming, cross-tool state, robust error recovery.
Outbound Vapi voice agents
50+ leads called per day. EU AI Act art. 50 disclosure, graceful human fallback, CRM integration.
Stripe Connect Express
Full marketplace: KYC, commission calc, monthly automated payouts, dual webhook verification.
Next.js 16 + Supabase
RSC, Server Actions, multi-tenant RLS, SSR cookies, Edge Functions. GDPR + EU AI Act compliant.
B2B outbound automation
50k+ leads enriched. Email sequences, intent detection → escalation to Vapi voice agent.
Multi-modal authentication
Passkeys WebAuthn, Google SSO, magic links, OTP for e-signature workflows.
Packages
Ready to sign. No fuzzy quotes.
Fixed price, clear deliverables, defined timeline. 50% deposit on signing, 50% on delivery. EUR or USD.
1-day Discovery
1 day
Express audit + priority recommendations + 30-day roadmap. Compact format to kick off and qualify the scope.
$900
AI audit + 90-day roadmap
3 days
Full technical diagnostic of your product, actionable recommendations, prioritized 90-day roadmap.
$2,900
Claude tool-use MVP
5 days
Agent in production with tool-use, human approval gates, streaming. Documented, deployed, knowledge transfer.
$4,900
Vapi voice agent in prod
5 days
Outbound agent configured, integrated to your CRM, webhooks, AI Act compliance.
$5,200
Stripe Connect marketplace
8 days
KYC onboarding, commission calculation, automatic payouts, dual webhook, ambassador dashboard.
$7,800
Next.js feature sprint
10 days
Complete RSC + Server Actions + RLS Supabase feature, production-ready.
$9,200
Custom day rate
Per day
For evolving scope. 3-day minimum, short or long engagements, 50% deposit.
$1,100
Process
Brief to delivery in 5 steps.
You send a brief
15-min Calendly or the form below. Three lines: business outcome, current stack, deadline.
We qualify in 15 min
I tell you if it's a match, what format (fixed-price or day rate), realistic timeline.
Proposal within 24h
1-2 page proposal: deliverables, milestones, fixed price. Valid for 7 days.
Deposit + kick-off
50% deposit triggers start. Daily async, weekly demo if > 1 week.
Delivery + handoff
Code on your repo, README, 30-min knowledge transfer. Free bug-fix window: 14 days.
About me
Sacha Praljak.
Sacha Praljak
Founder Kryva · Based in France · Remote with EU + US clients
I built a complete B2B SaaS solo in 4 months: AI voice-driven quoting, Stripe billing, KYB workflow, e-signature, compliant accounting. Plus a Claude agent with 40+ tools, an outbound Vapi voice agent, an ambassador system with Stripe Connect and automated monthly payouts.
Before Kryva: 8+ years in tech, 5 of which on B2B products in production (SaaS, fintech, marketplaces). Stack: Next.js 16, Supabase, Claude API, Vapi, Stripe Connect, Apollo, Resend. Fluent in English — worked with US, UK, NL, DE teams.
FAQ
Frequently asked.
When can you start?+
This week. Immediate availability — I can dedicate full-time to your project.
Day rate or fixed-price?+
Fixed-price preferred when scope is clear (deliverables + timeline + fixed amount). $1,100/day for evolving scope.
Time zone overlap?+
I'm in CET (Paris). I typically work 9am–7pm CET = 3am–1pm PST = 6am–4pm EST. Daily 1-hour sync with US East Coast is easy; West Coast works in async + 1-2 calls/week.
Long engagements (3+ months)?+
Yes — 1 week, 3 months or 6 months, I commit full-time as long as scope and deliverables are clearly defined.
NDA / confidentiality?+
Yes, I sign your standard NDA. For sensitive projects, I offer my own mutual NDA template.
Payment terms?+
Wire or Stripe (link provided on signing). 50% deposit, 50% on delivery. Engagements > $5,000 can be split in 3 milestones.
Invoicing?+
French sole proprietorship. EUR or USD invoicing, all legal mentions. Reverse-charge VAT for EU clients with valid VAT number. US clients: no VAT.
What if I'm outside EU/US?+
No problem — I work remotely worldwide. Contracts in English, EUR or USD via Stripe or Wise. Expect some time-zone friction; async + 1-2 sync calls/week works.
Available. Now.
Start this week.
Still reading? You have a need. 15 minutes to qualify it.
Book 15 minutes