Senior Full-Stack Developer Agentic AI Engineer

Den JansenFlores

I build systems for the hours when assumptions fail: operational SaaS, full-stack platforms and agentic AI workflows engineered to keep their answers straight under pressure.

Muntinlupa City, Metro Manila, UTC+8

About Den Jansen Flores

Full-stack engineering for systems that cannot afford to lose control.

I am a senior full-stack developer and agentic AI engineer based in Muntinlupa City, Metro Manila. I build operational SaaS, secure web platforms and agentic AI workflows for teams here and abroad. The work covers healthcare operations,courier logistics andAI-assisted analysis. I own the schema, access rules, server logic and interface. A weak seam is enough to compromise the whole system.

Requirements rarely arrive complete. I trace the job from one end to the other: who touches the record, which decision follows, and where the truth lives today. Often it is split between a wall calendar, a group chat and one person's memory. The point where that chain breaks is where the product begins.

I assume every shortcut will eventually be found, usually at the worst possible hour. Access rules stay close to the data. Every state has a name. Recovery paths are designed before the demo because a system reveals its quality when the ordinary path is gone.

Working with me is straightforward. We agree on the boundaries before the build starts. Updates come directly from me. If a feature has no business value, I say so before it reaches the invoice.

The visible half is easy to recognize: a clear interface, a direct explanation and a client who knows what the system will do.

The other half stays out of sight. I read the logs, test the case nobody raised and put the system under the conditions it will meet outside the demo. When that work is done properly, the silence is the evidence.

Projects

Seven case studies cover healthcare, logistics, workforce operations, commerce and AI-assisted analysis. Each file names the business problem, the architecture, the work I owned and the current state of the deployment and source. The evidence is there to inspect.

Smiley dental platform interface showing the clinic portal and appointment view.

Smiley

Independent dental practices often fall back to shared spreadsheets because practice software is priced for larger groups. A platform that serves several clinics must keep every patient's data inside the correct tenant without relying on developer memory.

Smiley serves several clinics from one application. The data layer enforces tenant scope, each practice has a branded subdomain, and records, schedules and reminders inherit the clinic boundary by default.

Next.js, TypeScript, Supabase, PostgreSQL

Open the case file

Full-stack and agentic AI capabilities, proven in the work

A stack list says what someone has touched. It does not say what they can carry. Every capability below points to a shipped project or to this portfolio. If the evidence is not here, the claim is marked that way.

What I can be hired to own

  • Full-stack web application development

    Complete web systems, from PostgreSQL schemas and access rules to server logic and the React or Next.js interface.

    Review this service
  • Operational SaaS development

    Scheduling, dispatch, records and workforce platforms with multi-tenant architecture and role-based access control.

    Review this service
  • Agentic AI engineering

    Applications where models call typed tools, return schema-validated output and carry state through guarded, multi-step workflows.

    Review this service
  • Data platform and workflow automation

    Ingestion, normalisation and validation pipelines that feed dependable analysis and reporting surfaces.

    Review this service

Product and systems engineering

I turn the real operation into rules the data can enforce.

  • Domain modelling

    Appointment lifecycles, shipment states and ticket threads mapped from the operation itself.

    ClinicFlow, Biyahero Express, ShiftDesk

  • Multi-tenant architecture

    Per-practice isolation with subdomain routing.

    Smiley

  • Role-based access control

    Role-separated portals where every user can reach only the records their role allows.

    ClinicFlow, ShiftDesk, Career Path

  • Operational workflow design

    Scheduling and availability, dispatch and COD reconciliation, GPS-verified clock-in.

    ClinicFlow, Biyahero Express, ShiftDesk

Backend and data

The rules stay where a skipped screen cannot bypass them.

  • PostgreSQL

    Relational models behind scheduling, dispatch and ticket lifecycles.

    ClinicFlow, Smiley, Biyahero Express, ShiftDesk

  • Supabase auth and row-level security

    Sessions, tenant boundaries and row-level policies protecting deployed systems.

    ClinicFlow, Smiley, Biyahero Express, ShiftDesk, Data Analysis Platform

  • Next.js server routes

    The server half of five deployed SaaS builds.

    ClinicFlow, Smiley, Biyahero Express, ShiftDesk, Data Analysis Platform

  • Node.js and Express

    The API layer behind the student assessment platform.

    Career Path

  • MongoDB

    Document storage where the assessment shape changes between cohorts.

    Career Path

  • Data ingestion pipelines

    Uploads are normalised and validated before the analysis stage sees them.

    Data Analysis Platform

Frontend and interface

Interfaces built for live data, impatient users and the screen already in their hand.

  • React

    Component systems across five deployed applications.

    ClinicFlow, Smiley, Biyahero Express, ShiftDesk, Career Path

  • TypeScript

    Typed contracts across the interface, data layer and API boundary.

    ClinicFlow, Smiley, Biyahero Express, Career Path, Data Analysis Platform, The Thrift Store

  • Next.js

    Six deployed applications, server and client boundaries included.

    ClinicFlow, Smiley, Biyahero Express, ShiftDesk, Data Analysis Platform, The Thrift Store

  • Tailwind CSS

    Token-driven interface systems, including the one you are reading.

    ClinicFlow, Smiley, Biyahero Express, ShiftDesk, Data Analysis Platform, The Thrift Store

  • Accessible interface patterns

    Keyboard navigation, native disclosures, semantic landmarks and tested contrast on this site.

    This site

AI-assisted workflows

Models do useful work inside clear permissions, schemas and failure boundaries.

  • OpenAI API

    The analysis stage of the ingestion pipeline.

    Data Analysis Platform

  • Structured model output

    Schema-constrained responses the interface can render without interpretation.

    Data Analysis Platform

  • Prompt orchestration

    Prepared context, explicit output shapes and iteration against observed failures.

    Data Analysis Platform

  • Claude API and tool useEvidence outside this portfolio

    Used in client and internal work. The evidence sits outside this portfolio, so the capability remains unverified here.

Deployment and operations

A build counts when people can reach it and the evidence still holds.

  • Vercel deployment

    Six live deployments, each linked and status-checked on its project page.

    ClinicFlow, Smiley, Biyahero Express, ShiftDesk, Data Analysis Platform, The Thrift Store

  • Public repositories

    Six builds have public source. The private repository is labelled without ambiguity.

    Smiley, Biyahero Express, ShiftDesk, Data Analysis Platform, Career Path, The Thrift Store

  • Astro static delivery

    This portfolio ships as static HTML with no client-side framework and no hydration.

    This site

  • Deployment verification

    Every deployment link is opened, checked and dated before its status is published.

    This site

How I build software that survives pressure

I map the real operation, keep authority close to the data and name the failure states before launch. AI remains one controlled stage inside a larger system. Each rule below points to the work that tested it.

Map the operation before choosing the stack

The workflow writes the schema.

A clinic appointment and a courier shipment obey different rules. I trace the real process first, then choose the tools. It costs more attention in week one and prevents a careless rebuild in month six.

Evidence

One appointment row with explicit status transitions in ClinicFlow. A shipment lifecycle with proof of delivery and cash reconciliation in Biyahero Express.

Own the whole chain

Responsibility runs from schema to interface.

I write the data model, server logic, access rules and interface. I also answer for how they behave together. When a system fails at two in the morning, the handoff chart is irrelevant. Ownership is not.

Evidence

Every project here was built end to end. Each project page lists exactly which parts, so the claim can be checked instead of believed.

Keep authority close to the data

A missed interface check should never become a disclosure.

The database enforces row-level policies and tenant boundaries. A conditional in a component may improve the interface, but it does not decide who can read a record. That decision belongs at the boundary an attacker cannot skip.

Evidence

Row-level security across role-separated portals in ClinicFlow. Per-practice isolation with subdomain routing in Smiley.

Put the model inside a controlled system

Prepared context in. Validated output out. Cost known.

The model call is one stage. The surrounding code decides what context it receives, which tools it may use, what shape it must return and how the system recovers when it fails. Intelligence without control is still a liability.

Evidence

The ingestion and analysis pipeline in the SaaS Data Analysis Platform: normalise, prompt, validate the shape, then render.

Design the recovery before launch

Every state needs a name, a transition and a way back.

Operational software fails at the edges: a double booking, a delivery completed twice, cash that never reconciles. I design those paths before the demo. The edge cases are where a system reveals what it was built to survive.

Evidence

Booked, confirmed, completed and cancelled as states on one appointment row. Ticket lifecycles with threaded history in ShiftDesk.

Reputation is useful. Evidence is better.

Four years of project-based engineering are documented through complete case studies, public repositories and dated deployment checks. Employer timelines, client counts and performance figures stay off the page unless published evidence can carry them.

Years building web systems
4+
Builds documented here
7
Live deployments, linked
6
Public source repositories
6

My experience comes from four years of independent and client work on complete systems. The record is project-based, and every case study states which parts were mine.

Deployment links were opened and checked on . One build, Career Path, is no longer hosted, so its page carries no live link. The record should be accurate even when the answer is less flattering.

Open to
Full-time roles, contract work, and freelance builds
Working hours
UTC+8, remote worldwide
Résumé
Sent on request by email

Direct answers for recruiters and clients

Location, availability, role fit, scope and the line between full-stack and agentic AI work. The answers are written plainly and remain readable without JavaScript.

Who is Jansen Flores?

Jansen Flores is Den Jansen Flores, a senior full-stack developer and agentic AI engineer based in Muntinlupa City, Metro Manila. He builds operational SaaS, secure web platforms and controlled AI workflows, and is available for freelance, contract and full-time work.

What does Den Jansen Flores do?

Den Jansen Flores is a senior full-stack developer and agentic AI engineer in Metro Manila, Philippines. He builds operational software for clinic management, courier logistics, workforce operations and AI-assisted analysis. He owns the chain from schema to interface because weak handoffs become production failures.

What is his primary stack?

His core stack is React, Next.js and TypeScript on the front end, with Supabase, PostgreSQL and Node.js behind it. He uses Tailwind CSS for interface systems. His AI work uses OpenAI and Claude APIs with tool calling, retrieval and schema-constrained output rather than a chat box added at the end.

What does he mean by agentic AI engineering?

Agentic AI engineering means a model does accountable work inside an application. It calls typed tools, retrieves grounded context, returns schema-validated output and carries state across several steps. The serious work is the control around the model: permissions, failure handling, observability and cost per run.

What roles is he open to?

He is open to senior full-stack, product engineering and AI engineering roles. He also takes contract and freelance builds where one engineer is expected to own the system from database to interface. Full-time employment and fixed-scope work are both in range.

Is he available for work?

Yes. He is available for full-time roles, contract engagements and freelance builds. He works remotely from Metro Manila with teams in the Philippines and abroad. Email floresjansen28@gmail.com. Replies usually arrive within one business day on UTC+8.

What industries has he built software for?

His documented work covers healthcare operations, dental practice management, courier dispatch, workforce systems, e-commerce, education assessment and AI-assisted business intelligence. Each sector links to a case study with the problem, architecture, ownership, source status and deployment status stated plainly.

What does working with him look like?

The rules are set before the build begins. He traces the real workflow before choosing the framework, keeps access rules close to the data and names the failure paths before launch. Updates come directly from him. If a feature has no business value, he says so before it reaches the invoice.

How can someone review the source or the live builds?

Every project page links to its deployment and, when public, its source repository. Private source is labelled private. Offline deployments are labelled offline. Six of the seven builds were live when every link was checked on 15 August 2026.

Where does his portfolio live online?

The portfolio is published at denforge.it.com, under the DenForge name. That is the canonical address for every case study, service page and machine-readable feed. The earlier address, jansen-dev.vercel.app, now redirects there permanently and should no longer be cited.

Where is he based, and does he work remotely?

He is based in Muntinlupa City, Metro Manila, Philippines, on UTC+8. He works remotely, covers Asia-Pacific business hours and can schedule early or late calls for European and North American teams when the work requires it.

Open a line

Bring me the system that fails after hours.

Tell me what breaks, who carries the cost and when you need it standing. If the problem is outside my range, I will say so before either of us wastes time.

Reply time
Usually within one business day (UTC+8)
Location
Muntinlupa City, Metro Manila, remote worldwide
Elsewhere
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