Haruan Justino

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1. Finetune (A Prometric Company)

   current
   Lead Software Engineer · Remote 09/2025 — present

   AP Classroom — College Board's platform for AP teachers and students.

   • Redesigned the partitioning strategy for the platform's largest dataset — ~3B score records and growing ~20% annually — on an S3 data lake queried via Redshift Spectrum, optimizing Parquet partitions for a new administrator- and coordinator-facing report at far larger scale, achieving 3× faster retrieval in testing; ran cost-estimation POCs to guide infrastructure trade-offs.
   • Architected the technical approach and led implementation of an epic merging AP Classroom's two most heavily used teacher-facing pages in React, working across legacy JavaScript and modern TypeScript, improving teacher workflows and platform performance.
   • Lead agile engineering workflows across a fully distributed remote team building a distributed system of services exposing REST and GraphQL (Graphene) APIs, balancing feature delivery with technical sustainability.

2. Wiley

   Lead Software Engineer · Hybrid 10/2024 — 09/2025
   • Architected a large-scale data platform in Java, Spring Boot and Hexagonal Architecture, processing millions of scientific articles — extracting licensing, territory and publication metadata and computing content metrics for clients building LLM training datasets and RAG applications. Its engineering standards were adopted across multiple teams.
   • Designed the platform's DAG-based orchestration on Airflow running on Kubernetes — pipeline structure, task dependencies and triggering strategy — and wrote the Python executed by each task.
   • Delivered a medical knowledge base API in two weeks with Python, AWS Chalice, Amazon Bedrock Knowledge Bases and OpenSearch, powering the debut of Wiley's Life Sciences AI Agent at an AWS event — 45 press articles, 145M monthly unique visitors of combined reach.
   • Built a Model Context Protocol (MCP) integration on top of that API in days, enabling and solidifying Wiley's strategic technology partnership with Anthropic.
   • Led a team of consultancy-provided engineers — hiring, mentoring and performance management — through an agile SDLC enriched with Lean and XP, delivering the core data platform on schedule with the company's top performance metrics: fastest PR turnaround, optimized test durations, highest code quality. Shared the team's processes company-wide through internal workshops.
   • Set the team's standard for responsible AI-assisted development — Claude, MCP, Copilot for code review, Playwright for test automation — and shipped a behavioral code analysis tool based on Adam Tornhill's hotspot methodology to guide technical-debt prioritization.

3. Finetune

   Senior Full Stack Engineer · Remote 04/2022 — 09/2024
   • Designed the reporting architecture for the platform's largest dataset — Redshift Spectrum external tables over Parquet on the S3 data lake, partitioned by classroom to serve student- and teacher-facing score reports.
   • Implemented core stages of the platform's layered Glue/PySpark ETL pipeline, where each stage produces inspectable, logged intermediate files, enabling recovery from any failure point without rerunning the full pipeline.
   • Optimized critical PySpark jobs, cutting execution times by nearly 50% and accelerating data availability and pipeline throughput.
   • Contributed to the Architecture Council, defining the platform's long-term architectural vision and technology roadmap.
   • Implemented collaborative assessment sharing with Python (Flask), React, PostgreSQL and REST/GraphQL APIs, significantly reducing rework in assessment creation.
   • Integrated Mock-SQS into local development, eliminating AWS infrastructure costs during development and streamlining testing.

4. Administrate

   Staff Full Stack Engineer · Remote 02/2021 — 04/2022
   • Rebuilt multiple legacy pages on a modern React and TypeScript architecture, improving performance and maintainability.
   • Implemented a full internationalization system for automated emails, enabling multi-language templates and expanding global reach.
   • Consolidated several legacy Custom Fields implementations into a unified architecture, cutting technical debt and complexity.
   • Added robust debugging capabilities to the PHP and Python codebases, accelerating troubleshooting for the whole team.

5. CrossKnowledge

   Senior Full Stack Developer · On-site 10/2018 — 02/2021

   Corporate learning platform.

   • Architected and led development of CK Connect, a five-service product built with Django, DRF, Vue.js and Docker — launched to positive industry reviews.
   • Designed and executed the migration of big data event logs and analytics from MongoDB to Snowflake using Redis and S3, resolving major bottlenecks.
   • Optimized the content suggestion system, reducing query response times from 30 seconds to 1.2 seconds.
   • Rebuilt local development environments for 8 projects with Docker, cutting onboarding from 2 days to 20 minutes.
   • Established Python coding standards with automated enforcement across the entire engineering department.

6. Revenda Mais

   Lead Software Engineer · On-site 12/2016 — 09/2018

   SaaS platform for automotive dealerships.

   • Migrated hosting from a single server to a distributed Nginx and Redis architecture, increasing SLA reliability for 600+ client websites.
   • Resolved deep database bottlenecks, supporting 25% more clients on the same hardware, and modernized image-processing workflows, cutting EC2 costs by 50%.
   • Created a centralized log and monitoring system covering 20 third-party integrations, reducing new support tickets by 50%.
   • Architected the platform's CRM module with PHP, Yii2 and SendGrid.

7. Earlier career

   iOS engineering, consulting & training 2011 — 2016
   • Blogo · iOS Engineer, 2015 — 2016 — architected the Blogo iPhone/iPad app, winner of the Apple App Store "Best New App 2016" award.
   • ENG DTP & Multimídia · iOS Consultant & Instructor, 2011 — 2015 — trained corporate development teams at Correios, Banco do Brasil and Prodam; published author ("Mac OS X Lion 10.7"); guided the team that delivered Brazil's official live election-count iOS app.

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