Cornerstone Develop

Code that holdsyour business

See what's behind every screen: clean code, organised data and security reviewed before every release.

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Who we are

Cornerstone
Develop

A cornerstone is the first block of a building: everything else lines up with it. That's what we do with your company's technology: software, data and security on a solid foundation.

Cornerstone Develop is the development studio of David Alvarado, a full-stack developer specialised in security, based in Guayaquil, Ecuador.

Our symbol: a </> code tag built from stone blocks. The yellow block in the corner is the cornerstone — the stone every piece of software is built on.

01

Software development

Web systems, mobile and desktop apps built around the way your company works.

02

Data and databases

Design, migration and optimisation of your data, with reports that update themselves.

03

Cybersecurity

Pentesting, code review and hardening so your system withstands real attacks.

01 · Software development

Software that fits your company

We don't sell templates. We learn how your team works and build the tool that fits, with clean code any developer can maintain.

FacturaService.csC# · .NET
public sealed class FacturaService(AppDbContext db, ISriClient sri)
{
    public async Task<Result<Factura>> EmitirAsync(Pedido pedido)
    {
        var cliente = await db.Clientes.FindAsync(pedido.ClienteId);
        if (cliente is null)
            return Result.Fail<Factura>("El cliente no existe");
        var factura = Factura.Desde(pedido, cliente, iva: 0.15m);
        db.Facturas.Add(factura);
        await sri.AutorizarAsync(factura);
        await db.SaveChangesAsync();
        return Result.Ok(factura);
    }
}

Sample snippet: issuing an electronic invoice.

Web systems

ERPs, customer portals and admin dashboards.

React / Next.jsAngular.NET

Mobile apps

Orders, inventory and collections from your phone, with offline mode.

AndroidiOS

Desktop

Point of sale, warehouse and invoicing, connected to printers and scanners.

WindowsOffline

APIs and integrations

We connect your systems to each other and to payment gateways, email or messaging.

RESTGraphQL

Cloud and DevOps

Hosting, backups and automated deployments without relying on a single PC.

AWSDockerCI/CD

Support and upgrades

Maintenance, new features and monitoring for systems you already have.

MaintenanceMonitoring

02 · Data and databases

Your data, in order and in sight

Your company's information is worth more when it's organised, backed up and ready to drive decisions.

  • 01

    Database design

    Clear models, the right indexes and automatic backups.

  • 02

    Lossless migrations

    From Excel, Access or legacy systems to SQL Server, PostgreSQL or MySQL.

  • 03

    Reports and dashboards

    Power BI connected to your real data, updated with no manual work.

SQL ServerPostgreSQLMySQLPower BIEntity Framework
stock_bajo.sqlSQL
SELECT  p.nombre                    AS producto,
        SUM(m.cantidad)             AS stock,
        MAX(m.fecha)                AS ultimo_movimiento
FROM    movimientos m
JOIN    productos   p ON p.id = m.producto_id
WHERE   m.bodega_id = @bodega
GROUP BY p.nombre
HAVING  SUM(m.cantidad) < 10
ORDER BY stock ASC;
Result · low-stock productsSample
White paint 4 L3
PVC pipe 1/2"6
Cement 50 kg8

03 · Cybersecurity

We find the flaws before an attacker does

We audit the systems we build and the ones you already run in production. We only test systems owned by the client, with a defined scope and prior written authorization.

Animation: a radar sweeps a client network and, under the cursor, an authorized security scan shows open ports and OWASP findings.
authorized-scan.logSimulation
OWASP Top 10

Web pentesting

We test your application the way an attacker would, with a defined scope and written authorization.

AppSec

Code review

We look for injections, logic flaws and exposed secrets before production.

Infrastructure

Hardening

Servers, databases and Cloudflare configured to reduce the attack surface.

Team

Training

Threat modeling and secure development workshops for your team.

audit-report.pdfSample
2
Critical
1
Medium
1
Low
  • CriticalA03SQL injection in /api/invoices● Fixed
  • CriticalA01Access to another customer's invoices (IDOR)● Fixed
  • MediumA05Missing security headers● Fixed
  • LowA07No login attempt limit● In progress

Every finding includes evidence, impact and steps to fix it.

Illustrative report: not from a real client.

Request an audit

04 · Projects

Real work, in production

Products we built that are already live: you can open them and try them right now.

Finance · SRI
Screenshot of the Nudo home page

Nudo

Invoices, expenses and deductions in one place: pull receipts from your inbox, verify them with the SRI and estimate your income-tax rebate.

nudo.alvarado-dev.comView project — Nudo

Android app
Screenshot of the Unísono home page

Unísono

Lyrics, chords and keys for worship teams, synced live and available offline.

app-alabanzas.web.appView project — Unísono

05 · How we work

Progress every week, not just at the end

  1. 1

    Analysis

    We learn how you operate and define scope, timeline and deliverables.

  2. 2

    Design

    You see the screens before any code is written, so changes cost nothing.

  3. 3

    Development

    We build in stages with a working demo every week.

  4. 4

    Audit

    We test security before going to production.

  5. 5

    Delivery

    We go live, train your team and stay available.

06 · Contact

Let's talk about
your project

Tell us what you need and we'll send you a scope proposal. The first meeting is free.

We usually reply within 24 hours

Write to us