Vitthal Mirji

Staff Data Architect · Scala | Spark | Databricks | GCP

Architecting retail/fintech/supply-chain/marketplace data platforms

🇩🇪 Available in Germany - can start immediately

India: +91-9845-630-306 · Germany: +49-177-9277127

[email protected]

vitthalmirji.com

github.com/vim89

linkedin.com/in/vitthal10

Download PDF resume

Summary	Staff/Principal-level Data Architect with 12+ years building contract-driven, developer-friendly data platforms for Walmart US, Walmart International and Deloitte Fortune 500 clients. I partner with product to define what to build (experience ecosystems, monetization surfaces, observability) and lead how to build using functional Scala, Spark/Databricks, Kafka/Flink, and Google Cloud. Targeting Staff Data Architect / Lead Data Platform roles across Germany, France, Netherlands, Finland or the UK. Community-first: creator of flowforge & toon4s, core contributor to llm4s, cask, scalasql, Speak in International conferences ScalaIO/Scala Days, and bootcamp instructor. Also open to Scala Engineering roles: Keen on functional programming, open-source contribution, clean code and software craftsmanship, using modern effect systems (Cats Effect, ZIO) and production-grade FP practices.
Key Accomplishments	Shipped six reusable frameworks (contracts, archetypes, monitoring, QA, ops) that cut delivery time from six weeks to two and reduced incidents by ~82% across 40+ teams. Monetized closed-loop merchant insights processing 100M+ daily records on Spark/Databricks, unlocking 75% business growth with sub-2h freshness. Modernized Deloitte estates (Aflac, Marriott, Eli Lilly), trimming infra spend by 62% (US$2.4M→US$900K) and boosting SLAs to 99.5%. Built DPAT automation + data-quality engines validating 5TB+/day at 99.9% accuracy, shrinking QA sign-off from three days to four hours. Open source: flowforge & toon4s creator, llm4s core contributor/GSoC mentor, Full-stack scala: cask, scalasql core contributor, ScalaIO/Scala Days/GDG speaker, corporate Scala/data-engineering trainer.
Core Skills	Architecture: Data contracts, streaming observability, governance, monetization products, code-generation platforms. Languages & Engines: Scala (Typelevel, Cats Effect), Python, Rust, SQL, Spark, Databricks, Flink, Kafka, Beam. Cloud: GCP (BigQuery, Dataproc, GCS, Pub/Sub), AWS (S3, Glue, EMR), Kubernetes, Docker. Leadership: Staff+ design reviews, roadmap definition, cross-team adoption playbooks, senior IC mentoring, incident/SLO programs.
Work	Walmart Global Tech Bangalore · Nov 2023 – Present Staff Data Engineer (IC5 / SDE5 Architect) Shape merchant analytics + supplier collaboration strategy, translating product bets into architecture & adoption roadmaps. Framework suite (contracts, archetypes, monitoring, QA, ops) now powers 40+ teams / 150+ engineers with 70% less boilerplate. DPAT automation + real-time observability cut QA sign-off from three days to four hours and MTTR by 60%. Mentor eight senior engineers on functional Scala, ADRs, and staff-level readiness. Walmart Global Tech Bangalore · May 2021 – Oct 2023 Senior Data Engineer / Tech Lead Led 13-engineer squad delivering closed-loop sales/inventory/supply-chain insights with 100M+ daily records and <2h freshness. Reusable Scala/Python APIs + CI/CD templates adopted by 12 teams for rapid domain onboarding. Improved supplier collaboration latency from 48h to 2h; forecasting accuracy +35% via streaming connectors. Optimized Spark/Dataproc cost by 40% while enforcing data-quality SLAs. Deloitte Consulting (U.S. offices) Mumbai · Apr 2017 – May 2021 Specialist Senior - Data Engineering Architected 350+ table EDW for Fortune 500 clients, increasing engagement revenue by 43%. Migrated 100+ TiB Hadoop workloads to AWS S3/Glue with zero data loss and automated reconciliations. Built Scala/Python ETL libraries ensuring 99.9% data accuracy; launched governance + SLA dashboards. Led pods of 6–8 engineers covering hiring, mentoring, and performance calibrations. Bista Solutions Inc. Mumbai · Feb 2016 – Apr 2017 Senior Data Engineer & Analyst Designed predictive demand platform for U.S. automotive clients (+5% sales, −10% inventory, +60% forecast accuracy). Implemented Spark Streaming + Kafka pipelines for real-time supply-chain telemetry. Nihilent Technologies Pune · Nov 2015 – Feb 2016 Data Engineer Created bash-based ingestion accelerators importing 1,000+ tables into Hadoop across 50+ programs.
Open Source	Author and core contributor to Scala data engineering libraries and AI frameworks spanning compile-time safety, functional pipelines, and LLM tooling. flowforge (github.com/vim89/flowforge): Type-safe Scala data-engineering toolkit with compile-time contract validation. Prevents schema drift before deploy. llm4s (github.com/llm4s/llm4s, 158 stars): Core contributor and GSoC mentor. Agentic LLM programming framework for Scala with multi-provider support. datapipelines-essentials-python (github.com/vim89/datapipelines-essentials-python, 55 stars): Simplified ETL process with Spark. Complete data lake pipeline with SparkSession extensions, DataFrame validation, SQL functions. toon4s (github.com/vim89/toon4s, 21 stars): Token-Oriented Object Notation for JVM. Reduces LLM token costs by 30-60% while maintaining JSON compatibility. compile-time-data-contracts (github.com/vim89/compile-time-data-contracts): Scala 3 macro-based schema validation with compile-time evidence. Pipelines don't compile if schemas drift. spark-spring-boot (github.com/vim89/spark-spring-boot, 7 stars): Apache Spark with Spring Boot support for rapid prototyping and enterprise integration. scalasql (github.com/com-lihaoyi/scalasql): Contributor to Li Haoyi's type-safe SQL library. Implemented COUNT and COUNT(DISTINCT) aggregation operations. cask (github.com/com-lihaoyi/cask): Contributor to Li Haoyi's Scala web framework. Added database transaction support and application configuration features. Rock the JVM Articles (RockTheJVM articles by Vitthal Mirji): Write articles on Rock the JVM abortable bytes: A POC on Kyo Effect system (github.com/vim89/abortable-bytes): a tiny scala/kyo POC that makes cloud uploads cancel-safe. Stream large files to cloud & clean-up on cancel spark-xml: Contributor to Databricks' Spark XML library. Data Pipelines Simplified:: Contributor to metadata framework.
Talks / Speaking	Scala.io Paris, France October 2025: Compile-time data contracts & Fiber-safe Data pipelines: Scala’s Effect system in action OAISYS - 2025 AI PRACTITIONERS CONFERENCE, Pune India November 2025: LLM4S: Build Reliable AI Systems in the JVM Ecosystem Scala India, September 2025: When Data pipelines fail early: Type-safe Data Engineering in Scala Scala Days: Speaker at Scala Days conferences on Scala functional data engineering. GDG & JUGs: Regular speaker at Google Developer Groups, Google Developer Expert and Java/Kotlin User Group meetups on Scala, Spark, and Data Architecture. Bootcamps: Run internal training on data engineering, functional programming for Fortune 500 teams. Publish 25K+ view technical articles on vitthalmirji.com covering type-safe data engineering, Scala patterns, and production lessons.
Education	B.E. Computer Science - Visvesvaraya Technological University, First Class, Jun 2015 (Belgaum, India). Diploma Computer Science - Bangalore University, First Class Distinction, 2010.
Certifications	Google Professional Data Engineer - Feb 2021. Cloudera Certified Spark & Hadoop Developer - May 2020. Sun Certified Java Developer - Java 5.x (2009), 6.x (2010).
Recognition	Walmart Bravo Award - 2024 & 2021. Walmart Wall of Fame - 2021-2024. Deloitte Outstanding Performance - 2019. Multiple Deloitte Applause Awards - 2017-2021. Best Academic Project (1st/15) - 2015, Gogte Institute of Technology.