What languages and technologies do you use for the backend?

Mostly Node.js with TypeScript, Go and Python, with SQL databases and PostgreSQL as the default choice. I pick based on what the problem calls for, not the other way around. Go when concurrency is the bottleneck, Python when there is data or models involved, and Node when the team already lives in TypeScript.

REST covers most cases well and is easier to cache and debug. GraphQL pays off when several clients need different shapes of the same data. I tell you which one fits your case before we start, and sometimes the answer is that you do not need GraphQL.

How long does a backend project take?

A scoped API can be in production in two or three weeks. A system with several integrations and a data migration runs into months. In the proposal I give you milestone deadlines, so you see real progress rather than a single date at the end.

How do I know it will hold up as we grow?

Because it gets tested first. I run load tests with a volume close to what you expect and show you where the ceiling is and what it costs to raise it. Better to learn that number in a test environment than on campaign day.

Do you handle the database too?

Yes, and it is usually where the most value is. I model the tables around the queries you will actually run, review indexes and take care of migrations. A badly planned model is paid for every month in performance and in hours.

What about security and personal data?

Authentication, role-based permissions and server-side validation come as standard. For personal data, encryption where it belongs and only the minimum stored. If your case requires it, we sign an NDA before getting into detail.

Can you work on an existing backend?

Yes, it is half of what I do. I start by understanding what is there and what hurts, usually with a performance or technical debt review. From there it gets fixed in stages, without stopping the business and without throwing it all away unless that genuinely pays off.

Do you handle deployment and maintenance?

Yes. I leave the project in the cloud with separate environments, CI/CD and monitoring. After that I can run maintenance on a monthly fee or leave it documented for your team to continue. You choose.

Solid APIs so your product does not go down on the day that matters

Backend and API development

7+ years building backends for startups and companies. Well-modelled data, architecture that takes the growth, and alerts when something breaks.

I want my backend built

The backend is what nobody sees until it fails

Nobody congratulates a backend that works. You notice it the day a campaign brings ten times the traffic, the day someone needs a report from two years ago, or the day a payment stops halfway. I work the three layers that decide that day, the API that serves, the data that holds it up and the infrastructure that warns you.

APIs and integrations

Documented and versioned REST and GraphQL APIs
Authentication, permissions and role-based access control
Integration with payment gateways, ERPs and third-party services
Webhooks and background jobs for whatever takes time

Data and performance

Database modelling built around the queries you actually run
Indexes and queries reviewed before the volume starts hurting
Caching where it pays off, not everywhere just in case
Data migrations without losing history along the way

Architecture and going live

Node.js, Go and Python, whichever the problem calls for
Cloud deployment with separate environments and CI/CD
Error logging and metrics so you find out first
Documentation and handover so your team can step in

Why build your backend with me?

No spaghetti code, no demo that falls over at a hundred users, no black boxes

Most backends I end up working on did not fail for lack of technology. They failed because nobody decided how the data was stored, because nobody measured how far it held up, or because the only person who understood it left. I build for that moment.

It holds on the busiest day
Load is tested before it actually arrives. Knowing where the ceiling is beats assuming there is none.
The data sits where it should
The model is designed around the queries you will run, not the other way around. Redoing it with a full database is as expensive as it gets.
You find out before a customer does
Error logging, metrics and alerts to a specific person. A silent failure always costs more than a loud one.
No black boxes
Documented API, decisions explained and code you can read. If someone else steps in tomorrow, they do not start by rewriting it.
Security from the start
Authentication, permissions and validation on the layer that counts, the server. Adding that later means touching everything.
You can change supplier
Repository, servers and accounts in your company name. If one day we go separate ways, the backend keeps running.

What I build on the backend

These are the jobs that reach me most often. If your case looks like one of them, I have built it before.

An API for your site or app

The service that feeds the frontend or the mobile app, with its documentation and permissions sorted.

Connecting systems that do not talk

Wiring up ERP, CRM and payment gateways so data moves on its own instead of being copied by hand.

Rescuing a slow backend

An API already in production that takes too long, with a diagnosis of what slows it down and the fixes applied.

Migrating to an architecture that holds

Moving the project out of a monolith that outgrew itself and into services, in stages and without stopping the business.

Automating heavy processes

Scheduled tasks, queues and background jobs for whatever must not block a request.

Getting a backend into production

Cloud deployment, separate environments, CI/CD and monitoring for a project that today only runs locally.

Tell me about your backend project

How I go from your problem to a backend in production

I work out what it has to take

How many users, which queries and what happens when something fails. The technical decisions come from that, not from this month’s trend.

I design the data and the API

The model and the contracts are settled before any logic is written. Changing them later is what turns a project into a rewrite.

I build with tests

Anything touching money or customer data ships with tests. Not out of purism, but because that is what lets you change it a year from now without fear.

I deploy and monitor

Production with separate environments, CI/CD and alerts. I show you how to read them so you do not depend on me to know how it is doing.

Is your API falling short, or does your backend go down when you need it most?

Tell me about it

Some of my clients

Testimonials

What the companies I have worked with say

Real projects, real teams. These are some of the people who trusted me with their backend.

★★★★★

"The project was delegated to us and Miguelo solved the hardest part: a multi-step, reusable certificate form with integrated payment. Clean design, fast loading and everything working from day one."

Alberto Fuentes

Web developer · project partner · Trámites Registro Civil

★★★★★

"We needed fast internal tools with Web3, and Miguelo built them in a couple of weeks. He left us a component base we keep building on faster."

Josep Bove

CTO · AAVE Chan

★★★★★

"We needed to launch fast and with a top-tier site. Miguelo built the landing and then the full DeFi, blazing fast and pixel perfect, even with a redesign in between."

Xavi Recio

CEO · Avem Finance

Tell me about your backend project

Common questions

Frequently asked questions about backend and API development

What people almost always ask me before starting a backend project.

What languages and technologies do you use for the backend?
Mostly Node.js with TypeScript, Go and Python, with SQL databases and PostgreSQL as the default choice. I pick based on what the problem calls for, not the other way around. Go when concurrency is the bottleneck, Python when there is data or models involved, and Node when the team already lives in TypeScript.
REST or GraphQL?
REST covers most cases well and is easier to cache and debug. GraphQL pays off when several clients need different shapes of the same data. I tell you which one fits your case before we start, and sometimes the answer is that you do not need GraphQL.
How long does a backend project take?
A scoped API can be in production in two or three weeks. A system with several integrations and a data migration runs into months. In the proposal I give you milestone deadlines, so you see real progress rather than a single date at the end.
How do I know it will hold up as we grow?
Because it gets tested first. I run load tests with a volume close to what you expect and show you where the ceiling is and what it costs to raise it. Better to learn that number in a test environment than on campaign day.
Do you handle the database too?
Yes, and it is usually where the most value is. I model the tables around the queries you will actually run, review indexes and take care of migrations. A badly planned model is paid for every month in performance and in hours.
What about security and personal data?
Authentication, role-based permissions and server-side validation come as standard. For personal data, encryption where it belongs and only the minimum stored. If your case requires it, we sign an NDA before getting into detail.
Can you work on an existing backend?
Yes, it is half of what I do. I start by understanding what is there and what hurts, usually with a performance or technical debt review. From there it gets fixed in stages, without stopping the business and without throwing it all away unless that genuinely pays off.
Do you handle deployment and maintenance?
Yes. I leave the project in the cloud with separate environments, CI/CD and monitoring. After that I can run maintenance on a monthly fee or leave it documented for your team to continue. You choose.