Technical Integration Partner for Agencies & SaaS Companies

AI, API & Backend Integrations That Make It to Production

I help agencies and SaaS companies deliver complex AI, API and backend integrations without expanding their internal team.

15+ years building production systems, financial-services integrations and distributed backend platforms.

Tell me what you need to integrate See integration examples

Available for white-label agency work · Remote · Uruguay / US-friendly timezone

15+ years backend engineering
Financial-services systems
REST & SOAP integrations
OAuth / JWT / security
Production debugging

Integration & Backend Engineering

What I help with

When a project needs to connect to AI, external APIs or internal systems, I take that part to production.

AI integrations

LLM features grounded in your real data, with validation and guardrails.

Third-party APIs

CRMs, ERPs, marketplaces and SaaS platforms — REST or SOAP.

Backend systems

Services and data models built to run reliably in production.

Workflow automation

Turning manual workflows or no-code automations that have outgrown their limits into reliable production systems.

Payments & webhooks

Payment providers, event processing, retries and idempotency.

Legacy & enterprise

Connecting modern products to older or enterprise systems.

Authentication & security

OAuth, OIDC, JWT, permissions and secure data access.

Internal tools

Small apps that make your team's operations faster.

Selected Integration Work

Two live demos built on synthetic data. Each one shows a pattern I deliver for real projects.

AI Support Integration

Try the live demo ↗

Problem

Support teams spend hours answering the same account questions — billing, subscription status, why something was cancelled — by looking up data in internal systems.

Solution

An AI layer that answers those questions from verified account data. It can only see the authenticated customer's records, must retrieve verified data from real systems instead of guessing, and its answer is schema-validated before anyone sees it.

Integration flow

Customer question
Auth & permission check
Account data lookups (tool calls)
Schema-validated answer
Audit log + safe fallback

Why it matters

The point is not to let an LLM answer freely. It's to automate repetitive requests while permissions, data access and failure handling stay under your control.

Agency Automation Pipeline

Try the live demo ↗

Problem

Leads arrive through forms, email and other channels, and someone has to qualify them, look up the company, add them to the CRM, write a reply and tell the team — by hand.

Solution

A backend pipeline that runs all of those steps as one workflow. Each external service sits behind its own adapter, and if the AI step fails, a rule-based fallback keeps the pipeline moving.

Integration flow

Lead webhook
Validation
Company enrichment
AI qualification
CRM update
Personalized reply
Team notification

Why it matters

This is integration work agencies can sell to their clients without building the whole technical capability in-house.

White-Label Technical Partner

Your agency owns the client relationship. I handle the technical integration work behind the scenes.

I can join a project when you need help with:

✓AI integrations
✓Complex APIs
✓Backend architecture
✓Authentication and permissions
✓Payments and webhooks
✓Legacy systems
✓Third-party services
✓Data pipelines
✓Production debugging

You keep the client. I help you deliver.

Talk about a project

Products I've Built

I also build and ship complete products from idea to production — frontend, backend, payments and deployment.

Spanish-language products for small businesses in Latin America.

PrecioExpress

Instant-quote calculator for service businesses. Accounts, database and payments included.

Open ↗

Cataloguito

Mobile-first online catalog where orders go straight to the seller's WhatsApp.

Open ↗

TurnoConfirmado

Appointment confirmation by link, so businesses know about no-shows in advance.

Open ↗

CobroListo

Unpaid-invoice tracking with automatic reminders to customers.

Open ↗

Show more products (4) ↓

PropuestaSimple

Sales proposals shared by link and accepted in one click.

Open ↗

PuertaCRM

Minimal CRM for field sales reps who visit businesses in person.

Open ↗

ReseñaFácil

Review collection page with link and QR code for local businesses.

Open ↗

MeliMargen

Real per-sale profit calculator for MercadoLibre sellers.

Open ↗

Built for systems where integrations actually matter

15+ years working on backend and distributed systems, including financial-services integrations where reliability, security and external APIs are critical. That means I'm used to third-party providers, critical systems, legacy platforms and debugging in production.

15+ years backend engineering
Financial-services systems
REST & SOAP integrations
OAuth / JWT / security
Java / Spring
TypeScript / Node
SQL
Docker / CI/CD
Production debugging

Pricing

Fixed scope and a clear price before work starts.

Pilot

From $750

A small, contained project to prove the integration works.

–Small integration
–Technical validation
–Prototype / proof of concept
–Discovery + limited build

Integration Sprint

From $1,500

A focused implementation for one concrete integration or automation.

–API integration
–AI workflow
–Webhook / payment integration
–Backend automation
–Internal tool

Ongoing Technical Partner

Custom monthly capacity

For agencies or SaaS teams that need recurring integration and backend capacity without hiring another full-time engineer.

Have an integration you're not sure how to build?

Tell me what needs to connect, what system you already have, and where you're stuck. I'll tell you whether I can help.

Or email me at javier@sealionstudios.com