For businesses
I automate the process that eats your team's hours every week,
connected to the tools you already use.
- CRM
- Spreadsheets
- ERP
- AI agents
Jonathan CedeñoSenior software engineer · Barcelona
I automate business processes and take products to production, at a fixed price.
The person you talk to is the person who builds it. I design the architecture, review every delivery and stand behind it, with tests and security.
- Fixed price
- Project-based
- Remote and asynchronous
Demo: a customer asks for an appointment on WhatsApp; the AI agent checks free slots in Google Calendar, creates the booking and confirms it in the same chat.
Services
Two ways I help
Project-based, remote and at a fixed price.
For founders
I take your idea or prototype to production.
I build the product in phases, or audit and harden the one you already have, whatever tool it was built with.
- Security
- Architecture
- Tests
- Monitoring
Fixed quote after a 30-minute call.
Book 30 minutesCases
What I've already built
Three of my own products and three client projects, without names. Client figures are estimates, not measurements.
Own product · first client
Wedding invitations that also organize the wedding
1real wedding in production
An invitation site with real RSVPs and per-family links, plus a private dashboard for the couple: instant alerts, payment tracking, allergies and a seating plan you arrange by dragging. Now multi-tenant, on our own EU server, with nightly backups and restore drills.
- RSVPs
- Couple dashboard
- Seating plan
- Telegram alerts
- Multi-tenant
Own product
AI assistant for WhatsApp and web
31automated evals on every change
Answers in Spanish, Catalan and English and checks, creates and cancels bookings in Google Calendar. Multi-tenant, with a dashboard, prompt injection protection, 31 automated evals on every change and backup restore drills. No customers yet.
- Web
- Google Calendar
- ES · CA · EN
- Multi-tenant
Own product
Web platform with native iOS and Android apps
≈10weeks part-time, with AI agents
Multi-tenant, with the same features on the web and both apps, built in about 10 weeks part-time with AI agents. In beta.
- Web
- iOS
- Android
- Multi-tenant
- In beta
Client work
Custom portal for a work management company
40–60 hof work saved per weekEstimate
- BeforeA company of 60–80 employees ran time tracking, resources and work reports on paper, Excel and Word, with calculations done by hand.
- NowA single portal, from idea to launch, that organizes costs, reduces errors and keeps a record of changes.
It is still in use.
Client work
Portal for an installation company
80+employees; the portal is still in use
- BeforeA company of more than 80 employees installs water, heating and solar systems, and calculated each job by hand.
- NowA portal, from idea and market analysis to launch, that automates the calculation and assigns materials.
Results are more accurate and customers get a more detailed quote.
Client work
Event registration and payments
+500people signed up
- BeforeRegistrations came in over WhatsApp, and both sign-ups and payments were tracked by hand.
- NowA Next.js and Stripe app to register and pay online.
With an average ticket of €20.
- Next.js
- Stripe
I have also built
Own prototype · in development
A portal to run a team of AI agents
You hire agents by role, assign them tasks and watch them work live: they ask each other questions, delegate and hand in work for review, with budget control.
- Claude Agent SDK
- TypeScript
- Hexagonal
- 298 tests
Own prototype
An AI decision engine that learns from documents
A knowledge base built from uploaded documents, machine learning models and an engine that tests every strategy against historical data and in simulation before anything real, with a metrics dashboard.
- RAG
- Python
- Backtesting
- React
How I work
From the first call to delivery
- 01
30-minute call
You tell me what you need. I'll tell you whether I'm the right person, and if I'm not, I'll say so.
- 02
Fixed quote
A fixed price after the call, before any work starts.
- 03
Built in phases
I design the architecture and build in phases. I use AI agents to shorten timelines.
- 04
Reviewed delivery
I review every delivery and stand behind it, with tests and security.
- You talk to the builderNo middlemen.
- Fixed pricePer project, not per hour.
- AsynchronousWritten updates and short recorded demos.
- RemoteFrom Barcelona.
FAQ
What people usually ask
How much does a project cost?
It depends on the scope, so I don't publish a rate. It is always a fixed price, agreed after the 30-minute call.
Does it work with the tools we already use?
That is the point: I connect what you already use (CRM, email, spreadsheets, WhatsApp or your ERP).
What about our data and GDPR?
We sign a data processing agreement, I use only the data that is strictly needed, with scheduled deletion, and what I build is hosted in the EU.
Will the AI assistant handle our customers on its own?
It shouldn't. The assistants I build hand the conversation over to someone on your team when the customer asks or when the agent can't solve it.
What happens after delivery?
It includes 30 days of bug fixes. After that, if you want, maintenance for a fixed monthly fee with no lock-in.
Whose name are the service accounts in?
We decide it for each project: in your name, paying each provider directly, or in mine, included in a monthly fee. The quote makes it clear.
I built an app with AI. Can you make it ready for real customers?
Yes, whatever tool it was built with. I audit and harden security, architecture, tests and monitoring, or build the product in phases.
Do you use AI to write code? Is that reliable?
I use AI agents to shorten timelines, but I design the architecture and review every delivery, with tests and security. My WhatsApp assistant, for example, runs 31 automated evals on every change.
How do we communicate?
I work asynchronously: written updates and short recorded demos. Spanish calls are fine; my spoken English is limited.
About
Jonathan Cedeño
More than 7 years in software engineering: firmware, automotive testing, technical leadership of web and mobile apps, portals for construction and installation companies built from idea to launch, and my own AI products. I live in Barcelona.
- Experience
- 7+ years
- Based in
- Barcelona
- Engagement
- Remote, per project
- Languages
- Spanish · written English
- Availability
- Immediate
Another project?
In 30 minutes I'll tell you whether I'm the right person, and if I'm not, I'll say so.
Jonathan CedeñoThe person you talk to is the person who builds it.
or email me athola@jcedeno.es