Mateus Pereira

Mateus Pereira · Florianópolis, Brazil

Software engineer building real products across web, mobile, and backend.

I'm a software engineer based in Brazil, with over two years working remotely on a US software company's product team. I work mostly in TypeScript and React, shipping production features, backend services and mobile apps.

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Selected work

Real-time collaboration platform

Pivot Technologies

  • US startup
  • 2024–present
  • Contract software developer, remote

Pivot is a collaboration product with chat rooms, video calls, a block-based page editor and shared spaces, used for cohort-style teaching. I work on it as part of a small product team. These are the pieces I built or co-built.

Pivot page editor with a Section block containing a Create event form (name, start and end date and time, room options), followed by a Tabs block with Tab 1 and Tab 2.
A Pivot page using the Section, Event and Tabs blocks I built for the editor.

Breakout groups

I built the breakout-groups feature: a host splits a live room into groups, auto-assigns participants and starts them. I later tracked down and fixed a roster bug in it.

PRs #5320, #8292

Instructor splits a live lab into two breakout groups and starts them.

Block editor

I built the Section, Event and Tabs blocks for the rich-text page editor (Lexical). I also fixed a caret and IME bug caused by save echoes, and added a regression test so it stays fixed.

PRs #6448, #5274, #10336

Building a page with the slash menu: a Section containing an Event and a Tabs block.

Notifications

I co-built the notification backend: 10+ gRPC methods, push delivery through Expo, reminders, notification preferences and pagination. The inbox UI shown is a teammate's; the notifications in it come from the service I worked on.

Pivot inbox with one unread notification: 'Amara Okafor replied in a thread you follow in Study Group · Hash Tables', with a message preview and timestamp.
A thread-reply notification in the inbox.

Screenshare zoom

I added zoom to shared screens in calls, so students can read small slides and code without leaving the room.

PR #4003

Student view of a shared slide on linear probing (hash slots k7, k4, k1, k2) zoomed to 120%, with participant tiles below.
A student zooms a shared slide to 120%.

Also: German localization rollout (4 of 7 i18n PRs, including the foundation) · Go gateway and authorization fixes · Marketing-site redesigns · Real-time messaging fixes

Dental clinic management

Serodonto

  • Brazil
  • 2023–2025
  • Software engineer (intern → full-time)

Serodonto is clinic-management software used by hundreds of dental clinics. As part of the product team I helped build the React Native app (20+ screens) for scheduling and day-to-day clinic workflows, wired it to backend APIs and WhatsApp messaging, and helped release it on Google Play and the App Store. The Android app lists 1,000+ downloads.

Google Play (opens in a new tab) ↗App Store (opens in a new tab) ↗

  • Serodonto agenda for Friday 7 June 2024: week strip, and two scheduled general-dentistry appointments at 12:30 and 13:30 tagged Agendado and Avaliação.
    Daily agenda with appointment cards and status tags.
  • Serodonto agenda in selection mode: header '2 selecionados' with delete, block and edit actions, and the 09:30 and 10:00 slots selected.
    Select several time slots to block, edit or delete.
  • New appointment sheet with fields for patient search, insurance plan, specialty (Clínica Geral), frequency (Agendado), occurrence and two observation fields.
    Booking form: patient, insurance, specialty.
  • Booking sheet with 'Primeiro Agendamento' toggled on, showing inline fields to register a new patient: full name, preferred name, phone, birth date, insurance and specialty.
    Register a new patient inside the booking flow.
  • Ver Consulta edit sheet: date and time 14/05/2024 10:30, insurance Particular, frequency Agendado, occurrence Ativar, with Salvar and Cancelar buttons.
    Editing an existing appointment.
  • Answer-anamnesis screen with question types: multiple choice, checkboxes, and a searchable dropdown list of options.
    Configurable anamnesis questionnaire.

Real app screens. The interface is in Portuguese.

Engineering impact

Testing and CI reliability at Pivot

Beyond features, I spent time making the team's feedback loop faster to trust: when CI is red, it should mean something.

18.7% → 0.8%
of E2E specs missing from shard-timing data, after I automated the refresh
51
Playwright spec files added
  • Measured the wasteSampled CI and found 36.9% of jobs over a 16-hour window ended failed or cancelled.
  • Gated expensive jobsCostly jobs no longer start after the cheap checks have already failed.
  • Quarantined flaky testsBuilt a quarantine for known-flaky tests and root-caused the recurring ones.
  • Debugging toolsBuilt internal tooling: a local lab environment and a CLI for pull-request operations.

About

Most of my career so far has been on production apps, and I like working across the stack: a React screen, the API behind it, and the push notification that points back to it.

For the past two years I've worked in a small remote team with US colleagues, on overlapping hours. I'm finishing a B.S. in Information Systems at UFSC (expected December 2026) and live in Florianópolis, Brazil (UTC-3).

Languages
Portuguese (native) · English (professional)
Tech
TypeScript · React · Next.js · React Native · Node.js · Go · gRPC · Playwright · PostgreSQL

Let's talk

I'm open to frontend and full-stack roles at product companies, remote from Brazil with overlap on US hours. The quickest way to reach me is email.

mateus.sle.per@hotmail.com

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