// 01 / IndexSenior Software Engineer
// Based inSão Paulo, Brazil --:--:-- BRT

Engineering high-performance web products for millions of users.

I'm Guilherme Illescas — a senior full-stack engineer obsessed with the millimeter craft of interfaces. Currently shipping AI sales infrastructure at AwSales. Before that: led product engineering at Conquer (10M+ certificates issued) and co-founded Amank (acquired in 2024).

See selected workLet's talk
0M+
users reached across products in production worldwide.
0K+
active customers maintained across high-uptime platforms.
0%
average performance gains delivered through targeted refactors.
0yr
shipping production-grade software, from startups to scale-ups.
// 02 — ABOUT
The engineer

A craftsman, not a code monkey.

I believe great software is invisible — until you compare it with the alternatives. The interfaces I build aim for that: fast, deliberate, accessible, and quietly opinionated.

Six years into my career, I've designed and shipped applications used by over a million people worldwide. I've led teams, built design systems, refactored legacy codebases, founded a SaaS that was acquired in 2024, and learned that the best engineers obsess equally over performance, copy, and user feeling.

I'm currently a Senior Software Engineer at AwSales, where I help build autonomous sales agents at the frontier of AI. When I'm not coding, I'm probably teaching, reading on systems thinking, or planning my next side project.

~/guilherme.json
role
Senior Software Engineer
based
São Paulo, BR
company
AwSales — Full-time
local time
--:--:-- BRT
status
● Open to talks
timezone
UTC−3 (BRT)
Currently working with
  • React 19
  • Next.js 15
  • TypeScript
  • React Query
  • Nuxt 3
  • Prisma
  • Tailwind v4
  • Node.js
  • Stripe
// 03 — EXPERIENCE
Career, as a changelog

Releases v2.0 → v8.0.

Each role is a major version. Each bullet is a real change shipped — features, refactors, leadership. No fluff.

07releases shipped
  1. v8.0.0guilherme/careerawsales
    Jul 2024 → present1y 4mo · current
    RoleSenior Software EngineerFull-time · Remote

    Building autonomous AI agents for sales and support — Brazil's leading AI-native sales platform. Integrations with Stripe, Meta WhatsApp API, Hotmart and beyond.

    Shipped customer platform features end-to-end, co-defining UX with Product and Design
    Built and maintained the internal back-office app on Nuxt + Node
    Led core integrations: Stripe billing & subscriptions, Meta WhatsApp API
    Cross-squad collaboration: customer platform (8 ppl) + back-office (3 ppl)
    Drove product discovery — proposed simpler journeys, aligned roadmap with business outcomes
    • Next.js
    • React
    • React Query
    • Tailwind
    • Prisma
    • Nuxt
    • Node.js
    • Stripe
    • GCP
    • Docker
  2. v7.0.0guilherme/careerprevidenciarista
    Nov 2023 → Sep 20251y 11mo · freelance
    RoleSenior Software EngineerFreelance · Remote

    Maintained mission-critical SaaS platform serving 27K+ active customers performing pension calculations. Owned the marketing site, SEO and core stability.

    Improved site performance by +22% (Core Web Vitals & Lighthouse)
    Lifted SEO scores by +9% via structured data, GA & GTM
    Refactored hot paths — overall app efficiency up +29%
    Established testing baseline with Jest (unit) and Playwright (e2e)
    • Next.js
    • TypeScript
    • Tailwind
    • Playwright
    • Jest
    • SEO
  3. v6.0.0guilherme/careerescola-conquer
    Oct 2022 → Oct 20231y 1mo · full-time
    RoleLead Software EngineerFull-time · Hybrid

    Led engineering on Conquer Plus — an education platform that issued 10M+ certificates to 35M+ students globally. Owned every phase: architecture, tech selection, delivery.

    Drove team growth — mentored engineers, set hiring bar, ran 1:1s
    Established internal Design System in Figma + code, wired with Storybook
    Architected micro-frontends with Single SPA — independent deploys per domain
    Tuned performance via Lighthouse audits and bundle splitting
    Delivered tech talks to widen impact beyond the team
    • Next.js
    • TypeScript
    • Single SPA
    • Storybook
    • Styled Components
    • Jest
    • Leadership
  4. v5.0.0guilherme/careeramank → bhub
    Aug 2022 → May 202310mo · founder
    RoleCo-founder & Senior EngineerFounder · Hybrid

    Co-founded Amank — a SaaS management platform helping companies centralize and reduce software costs. Acquired by BHUB in 2024.

    Built the product interface from zero — usability, performance, scalability
    Co-shaped product strategy, end-to-end features, architecture
    Acquisition outcome — Amank was acquired by BHUB in 2024
    • Next.js
    • TypeScript
    • Styled Components
    • Storybook
    • REST APIs
    • Founding team
  5. v4.0.0guilherme/careerdobank
    Jun 2021 → Dec 20217mo · freelance
    RoleMobile Software EngineerFreelance · Remote

    Built the DoBank mobile app from scratch — core architecture, UI, GraphQL data layer.

    Developed every screen using React Native, focused on UX and security
    Engineered the GraphQL data layer for efficient API consumption
    • React Native
    • GraphQL
    • Jest
    • Styled Components
  6. v3.0.0guilherme/careerchamer-tech
    Mar 2021 → Sep 20217mo · freelance
    RoleSoftware EngineerFreelance · Remote

    Drove e-commerce, dashboards and database integrations across multiple client projects.

    Implemented advanced SEO — +20% organic search rankings
    Optimized app performance — reduced load times across platforms
    • React
    • TypeScript
    • Jest
    • REST APIs
    • SEO
  7. v2.0.0guilherme/careerwebtrip
    Jan 2020 → Nov 202011mo · full-time
    RoleJunior Software EngineerFull-time · On-site

    Where I cut my teeth — full-stack work, server maintenance and process automation in a small team.

    Automated 6+ internal reporting flows — manual data entry down 70%
    Designed 10+ process improvements, reducing turnaround time
    • HTML
    • CSS
    • JavaScript
    • DevOps
    • Suite CRM
// 04 — SELECTED WORK
Selected work

Things I've shipped.

// 05 — PROCESS
Behind the build

How this site was made.

Designed end-to-end with a documented system. Every token, motion curve, and copy choice is intentional — and openly published.

v1shipped Jan'26
01 / Concept

Career as a changelog.

Each role becomes a semantic version. Bullets become diff lines. Companies become git tags. The metaphor carries the entire experience section.

02 / System

Tokens before pixels.

Palette, type scale, 8pt spacing and motion easing locked in CSS variables before a single layout was drawn. One source of truth — globals.css.

03 / Motion

Movement with purpose.

Reactive grid, headline cascades, magnetic CTAs, scroll-linked timeline. Every animation guides attention or rewards exploration — never decoration.

04 / Voice

Show, don't tell.

Real numbers (35M+ users, 22% perf gains) over adjectives. Short imperatives in CTAs. Code-comment markers as section dividers. No buzzwords.

Read the full design systemView source on GitHub
// 06 — CONTACT

Got something worth building?

oi@guilhermeillescas.devSchedule a call