FIG.00 · OPERATORLAT 03.7°S · LON 38.5°W

Mariana
Castro

I build tools that turn complex systems into records that are legible, trustworthy and auditable.

I work where systems are hard to inspect. Public services, most recently.

Status: OperationalView Full Résumé

Specification

Discipline: Full-stack
Domain: Legible systems
Core stack: TS · Next · Node · PHP · Python · PG
Base: Ceará / BR
Independent: 8 systems
Source: 8/8 public
In production: 180+ municipalities
Intake: Open · 2026

MC · A RECORD OF BUILT SYSTEMS

§ 01 · Some Things I’ve Built

Flagship · N=04

Independent builds: I chose the problem, designed the system and wrote it, and the source is open for every one.

SYS.01

Lucid

Plain-language auditor for documents, measured against ABNT NBR ISO 24495‑1.

Fully deterministic, 24 detectors mark each passage that trips the reader, cite the clause they fired on and explain why, without writing a single word into the text.

Evidence

The fence between proof and signal is a CI step: the build fails if the deterministic core imports the model layer, and 2,500 tests pin each detector to the cases that broke it.

Full record

Deterministic text auditor that checks a document against verifiable criteria for clarity and structure, including those from ABNT NBR ISO 24495-1. Its 24 detectors flag passages that may hinder reading, trace each criterion to its source, and explain why, without altering a word of the text. When a rewrite arrives, from the author or a language model, the engine re-analyses it and separates what it can prove from what it can only signal, with the boundary between the two layers enforced by the build.

Field noteLucid: engineering applied to auditing document clarity

TypeScriptNext.jsTailwind CSSVitestStrykerdependency-cruiserGoogle Gemini

Live Source

SYS.02

Horizonte

A music player where the record has mass, and the mass bends the space around it.

One full-screen fragment shader bends the typography, the cover and the dust using the same gravitational field, with nothing drawn on top.

Evidence

Each record’s physics comes from its own audio descriptors: measured offline in Python, reproduced in the browser by a hand-written FFT held to the same numbers.

Full record

A music player where the record has mass and mass bends space. A single full-screen fragment shader deforms the monumental typography, album art and dust using the same gravitational field, with nothing drawn on top. Collection, album and track exist as one continuous change of scale rather than separate screens. Each record's physics comes from its own audio descriptors, measured offline in Python and reproduced in the browser by a hand-written FFT using the exact same numbers.

TypeScriptNext.jsThree.jsGLSLWeb Audio APIWeb WorkersPython & NumPyVitest

Live Source

SYS.03

Access Check

Audits any public URL against WCAG 2.1 AA and hands back the exact code to paste.

Weighted score, severity-ranked issues, per-element highlighting and colour-blindness / low-vision simulation, exportable as PDF or Markdown.

Evidence

Fixes that can be applied automatically are tested on a copy of the page and come back labelled verified, failed or unchecked, checked against the DOM, not read off a rule table.

Full record

Full-stack tool that audits public URLs against WCAG 2.0, 2.1 and 2.2, levels A and AA, and provides the exact code needed to fix each issue. Automatic fixes are tested on a copy of the page in a real browser without altering the audited site. It includes a weighted score, severity-ranked issues, affected-element highlighting, the real keyboard focus path, visual simulations, and PDF and Markdown reports. A Chrome extension also audits pages behind a login or running on localhost.

TypeScriptNext.jsTailwind CSSPlaywrightaxe-corePrisma ORMPostgreSQL

Live Source

SYS.04

Gauntlet

Tournament engine that turns group and knockout results into a live projection.

Standings and the qualification cut recalculate on every result and stream to any number of spectators over SSE; a what-if mode cascades hypothetical scores into the bracket.

Evidence

Monte Carlo title odds on a TypeScript/PHP standings engine checked against golden test vectors.

Full record

Full-stack tournament engine that turns group and knockout results into a live projection. Standings and the qualification cut are recalculated with every result and streamed to any number of spectators over SSE. Monte Carlo simulations estimate title odds, while a what-if mode cascades hypothetical scores through the bracket. The TypeScript/PHP standings engine is validated against golden test vectors.

TypeScriptNext.jsTailwind CSSVitestPHP & LaravelPostgreSQLPest

Live Source API Docs API Source

§ 01.b · Further Index

Archive · N=04

Urban Flow

Agent-based traffic simulation you can experiment on: close a street and watch the network reroute.

EvidenceThe whole run comes from a seed, and tests assert that the same seed reproduces an identical run. That reproducibility is what makes the A/B honest.

TypeScriptNext.jsWebGL2GLSLCanvas 2DWeb WorkersTailwind CSSVitest

Live Source

Full record

Deterministic, agent-based traffic simulation you can experiment on — every car follows the Intelligent Driver Model and routes by Dijkstra over the lane graph, so closing a street makes the network reroute and the congestion move somewhere else. Flow, speed and load are recomputed every tick into a thermal map, an optimizer sweeps every single-junction fix across a worker pool and ranks them by gain, and the whole thing runs from a seed: tests assert that the same seed reproduces an identical run — which is what makes the A/B honest.

Origin Trace

Finds the exact Wikipedia edit that introduced a sentence and determines whether it ever had a source.

Evidence278 tests drive a fake Wikipedia instead of the live API; one caps a full descent at 20 revision reads, so the O(log n) claim breaks the build if it ever regresses.

Next.jsTailwind CSSTypeScriptVitest

Live Source

Full record

Provenance tracer for any Wikipedia claim: with no AI and no guessing, it bisects a revision history thousands of entries long to find the exact edit that introduced a sentence — reading dozens of revisions instead of all of them — then classifies whether the claim was born with a source, had one retrofitted later, or never had one. It follows the sentence through rewordings by shared anchors, flags circular sourcing, and audits a whole article sentence by sentence into an evidence-health dossier.

Field noteThe cache that never hit once

Token Guard

Turns a product description into a complete, accessible design system.

EvidenceRepair moves only lightness, so the hue and chroma the model chose are provably untouched. A colour that cannot clear its rule is reported infeasible rather than quietly passed.

TypeScriptNext.jsTailwind CSSVitest

Live Source

Full record

AI-assisted design-token engine that turns a product description into a fully accessible design system — the language model owns creativity while a deterministic OKLCH engine verifies, repairs and proves every contrast decision, measuring the model itself with an evaluation harness instead of merely trusting its output.

Book Nest

A full reading platform built as a single Next.js app: library, feed, submissions and moderation.

Evidence400 seeded leave-one-out trials: hit-rate@4 ≈ 0.845 against 0.15 for random, and the test fails below 0.8.

TypeScriptNext.jsTailwind CSSJestPrisma ORMPostgreSQLNextAuth.Js

Live Source

Full record

Full-stack reading platform — library, feed, ratings, submissions and a moderation workflow, behind Google, GitHub and credentials auth. The recommendation rail is the part taken seriously: a pure, dependency-free module that blends a Bayesian-damped community rating with category affinity, tells the reader why each book was picked, and — holding no database — can be evaluated offline. A seeded leave-one-out harness hides a book each synthetic reader would love among distractors and reports hit-rate@4 ≈ 0.845 and MRR ≈ 0.766 over 400 trials, against a random baseline of ~0.15. The test fails below 0.8, so the number stays measured rather than remembered.

§ 02 · Professional Experience

Field Record · N=04

Systems running in production inside public institutions, with real users, real scale and continuity after I shipped them.

Apr 2025 – Present

Tech Lead & Full-Stack Developer

Computer Engineering and Systems Laboratory, Federal University of Ceará

Research grant · coordination

Technical lead of the ERP that runs project management for LESC as an EMBRAPII unit.

Replaced spreadsheet-driven processes with a decoupled architecture.
Built the financial simulation module for project prospecting, with an approval workflow and persisted results.
Moved activity reporting, review and signing into the ERP, DocuSeal replacing DocuSign since May 2026, retiring emailed PDFs and hand-set signatures that slowed payments and left reported work untraceable.

PythonFlaskReact.jsTypeScriptPostgreSQLDocuseal

Mar 2025 – Present

Full-Stack Developer

ÍRIS | Innovation and Data Laboratory of the Government of Ceará

Full-time

Full-stack delivery for the state government’s innovation lab, from citizen-facing applications to the internal automation the teams run on.

Architecture and technical lead of a plain-language auditor for public documents, currently in development.
Designed the levels, dialogue and every scene in CNH Popular, a pixel-art game that walks citizens through each step of the state’s subsidized driver’s-licence programme, and prototyped its mini-games with the team.
Orchestrated the political-articulation team’s invitation dispatch end to end in n8n, against the official WhatsApp API via Zion, replacing a manual send of 200 to 500 invitations made at least twice a week.
Still building the Ceará Sem Fome platform, which began under the Chief Scientist programme in partnership with ÍRIS and is maintained here today.

Shipped at ÍRIS

CNH Popular visits: 3,000+
invitations per run, 2× a week: 200–500

Next.jsTypeScriptTailwind CSSPHP & LaravelMastra AIStyled ComponentsPostgreSQL

Aug 2023 – Mar 2025

Continues at ÍRIS

Full-Stack Developer

Digital Transformation Chief Scientist Program (FUNCAP)

Directed end-to-end development of the web and mobile platform for Ceará Sem Fome, a state programme for food security and professional training for socially vulnerable populations.

Created the unified design system shared by the web and mobile products.
Built the CRUD for the programme’s kitchens, managing units and beneficiaries. The platform is where they are registered, not a reporting layer over another system.
Delivered the analytics dashboards used for monitoring and data-driven decisions.

Registered and reported through the platform

kitchens: 1,200+
municipalities: 180+
meals per day: 130k+
enrolled in courses: 20,000+

React.jsMantine UITailwind CSSPHPLaravelPostgreSQL

Mar 2023 – Aug 2023

Front-end Developer

Computer Engineering and Systems Laboratory (LESC)

Built the web and mobile interfaces for IoT-based monitoring of emergency medical devices.

Real-time tracking and status management for defibrillators and cardioverters.
State accuracy was the hard requirement: a wrong reading of availability, location or operating condition sends a team to the wrong place, double-books a device, or delays an emergency call.

Next.jsReact.jsReact NativeTailwind CSSExpo

§ 03 · About Me

Profile

I came to engineering through architecture and design, which is why shipping a feature only counts when the system it lands in can still be understood.

My journey in technology is dedicated to transforming public services through code. As a full-stack developer at ÍRIS (Government of Ceará’s Innovation and Data Lab), I engineer end-to-end digital solutions to modernize public service delivery, from AI-powered prototypes to secure APIs.

Previously, I directed the development of the Ceará sem Fome Platform, where I built a unified design system, data management interfaces, and analytics dashboards to support food security efforts for vulnerable populations.

My path runs from the built environment to the screen. I trained as an architect and urbanist (UFC), then took a master’s in Psychology researching autism and the built environment, with a focus on universal design and sensory-inclusive spaces for people who perceive the world differently. That question didn’t change when I moved into software; it only changed medium. I build full-stack systems where accessibility and legibility are measured, auditable properties rather than afterthoughts. It is the same attention to the person on the other side, now in TypeScript, React and Laravel.

Recent stack

Next.jsReact.jsTypeScriptTailwind CSSPHPLaravelPythonPostgreSQL

Mariana Castro — FIG.01 · OperatorCeará / BR

MarianaCastro

§ 01 · Some Things I’ve Built

§ 01.b · Further Index

§ 02 · Professional Experience

Tech Lead & Full-Stack Developer

Full-Stack Developer

Full-Stack Developer

Front-end Developer

§ 03 · About Me

Mariana
Castro