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Building in public · MADA · 6-agent LangGraph at $1.5B scale

Vinh X. Nguyen

Notes & Works · AI / Data Engineering
📍 Waterloo, Ontario, Canada 📨 nxv.can@gmail.com 💬 say hi via the chat ↘

This isn't a job hunt — it's a working notebook. I share what I'm building, breaking, and learning at the intersection of multi-agent LLMs, big data platforms, and the messy reality of getting analytics to be both fast and honest. Pick a project below and dive in; the chat in the bottom-right will happily nerd out with you about any of it.

~9 yrs· 7 sectors· 200B+ events· 99.97% reconciliation accuracy
🏦 Banking 💰 Insurance 🚗 Automotive 📊 Analytics / KPMG 🔐 PKI · Security 🛍 Retail / PoS 🎓 Education
$1.5B
transactions audited by 6-agent LangGraph (MADA)
200B+
events / 30TB text processed on AWS · Snowflake · Spark
1M+
mobile-banking users protected by Cert Pinning
99.97%
financial reconciliation accuracy (from 60%)

How I Work

Modeling: OLTP, OLAP, Star schema, Schema-on-read, Delta Lakes, SCD, Data Vault 1.0 & 2.0, Medallion.
Engineering: Led Big Data batch/streaming/ETL at 200B+ events, 30TB text on AWS + Snowflake + Spark + Databricks.
Agentic LLM: Accelerated time-to-insight with LLM-powered multi-agents using MCP, LangGraph, LangChain, and RAG analyzing $1.5B financial transactions.
Architecture: Architect Community Lead at TymeBank (GOTyme – 1M users); defined integration & data patterns across 5 engineering teams.
Cloud-First: Full-stack AWS (security, network, compute, messaging, analytics); Databricks; Snowflake.
Financial Impact: Detected multi-million-dollar revenue leakage. Improved financial reconciliation accuracy to 99.97%.
Mentorship: University lecturer & engineering mentor — ML, algorithms, blockchain, performance & cost optimization.
Sectors: Bank (GOTyme, UBS), Insurance (Manulife, Prudential), Automotive (Cox), Analytics (KPMG, Ryte).

Skills & Expertise

🤖 AI Agentic LLM

  • Multi-agent workflows (LangGraph, LangChain)
  • Model Context Protocol (MCP)
  • GPT-4, Claude, Qwen; RAG pipelines
  • Vector Databases, Dynamic Tool Calls
  • Financial Anomaly Detection Agents

🗄️ Data Modeling

  • OLTP / OLAP at 200B+ records
  • Star Schema, SCD Types
  • Data Vault 2.0
  • Medallion Architecture (500M+ events)
  • Schema-on-read, Delta Lakes

⚙️ Data Engineering

  • Spark (EMR/Glue), Databricks, Delta Lake
  • Kafka, Kinesis, SQS/SNS, DynamoDB
  • Batch, micro-batch & streaming pipelines
  • S3 + Glue Catalog, Snowflake, MySQL
  • AWS Lambda, Sagemaker, Jupyter

☁️ Cloud & Infrastructure

  • AWS: ECS, Kinesis, VPC, WAF, Route53
  • API Gateway, CloudFront, ELB, NAT
  • Snowflake: Snowpipe, Materialized Views
  • Databricks: Delta, Cost-optimization
  • IaC: Terraform, CloudFormation

📊 Analytics & Visualization

  • Tableau, PowerBI, QuickSight
  • Grafana, Datadog, CloudWatch, ELK
  • NLP: TF-IDF, Lemmatization, POS tagging
  • 30TB text processing, 30K req/day
  • Google Analytics (2M/mo)

🔐 Security & Systems

  • PKI, Certificate Pinning (1M+ users)
  • Blockchain, Cryptography
  • Event-driven, Backpressure, Async
  • QoS, MPLS, Load Balancing
  • WAF, VPC Peering, IAM

Things I've Built

Each card is a short blog post about a project — what I was solving, what surprised me, and what I'd do differently. No pitch decks, just engineering stories. Click any card to open the full write-up; share the URL and it lands right on the case study.

📌 Featured · long read
FPT Canada2024 → today · ~12 min read

🤖 MADA — teaching six agents to audit $1.5B

The story of why our deterministic checks kept missing the long tail, how a 6-agent LangGraph (Orchestrator → Ingest Auditor → Anomaly Detector → Evidence Retriever → Evaluator) closed it, and the messy bits: hallucination guardrails, retry loops, a self-learning rule memory, and a golden-set harness that keeps the LLM honest.

LangGraphRAGMCPAWSSnowflake
Read the full post →
FPT Canada2022 → today · ~8 min read

📊 200B+ events on a Bronze→Silver→Gold platform

How we got query latency from 30s to 8s, enrichment quality to 99.97%, and seven downstream teams to actually trust the same gold tables. Includes the partitioning calls I'd make differently today.

AWSSnowflakeSparkDelta Lake
Read the post →
FPT Canada2023 · ~6 min read

💰 Finding multi-million-dollar leakage in invoices

End-of-month spreadsheets → next-day automated reports. Lambda + Snowflake + DynamoDB, with SES routing findings to the right owner. The detection rate jumped from 30% to 99.99% — and the audit trail is what got me promoted to Data Integrity Lead.

LambdaSnowflakeSESTableau
Read the post →
FPT Canada2021 → 2024 · ~7 min read

🌐 Clickstream → omni-channel MDS at 10M entities

Stitching web, mobile, and back-office events into a single 10M-entity master data store. Where naïve identity resolution falls over, why Iceberg saved us, and how the Tableau dashboards finally stopped lying.

KinesisEMRIcebergMDS
Write-up coming soon
FPT Canada2024 · ~5 min read

🔄 Salesforce → Snowflake CDC without the drama

Why bulk syncs were costing us a CRM-shaped panic every Monday, and the streaming CDC pattern (Bulk API 2.0 + Snowpipe + dedup MERGE) that replaced it. Includes the schema-drift trap I walked straight into.

SalesforceSnowpipeCDCLambda
Write-up coming soon
GOTyme Bank2019 → 2021 · ~9 min read

🔐 Certificate pinning for 1M+ banking users

Every six months we used to force a mandatory app upgrade just to rotate a cert. This is the PKI + mobile SDK + zero-downtime rotation design that ended that pattern — and the architecture debates with the security team that made it stick.

PKIMobile SDKAWS EMRKinesis
Write-up coming soon
GOTyme Bank2019 → 2021 · ~6 min read

🏦 Shipping 4 banking products at once

Personal Lending, VAS, GoalSave Kicker, ID Payment — what it took (architecturally and politically) to ship four banking products from one platform without each team reinventing the wheel.

MicroservicesKafkaJavaAWS
Write-up coming soon
GOTyme Bank2020 → 2021 · ~5 min read

📈 500M-tx analytics pipeline for a bank that just launched

How we built a multi-source analytics layer that kept up with a brand-new bank's growth, without buying everyone a new BI license. Spoiler: the unsexy part was the medallion conventions.

SparkDeltaPowerBIMedallion
Write-up coming soon
NFQ Asia2017 → 2019 · ~7 min read

🔍 30TB of text, 50K req/day, one $10K/mo bug

The TF-IDF + lemmatization + POS-tagging pipeline behind a serverless SEO API — and the day I realised our Datadog bill was being padded by a logging defect nobody had noticed.

NLPAWS LambdaDatadogServerless
Write-up coming soon
NFQ Asia2018 · ~5 min read

🛍️ Real PoS hardware, very serverless backend

In-store PoS devices talking to API Gateway → Lambda → SQS → DynamoDB, auto-scaling on Black Friday without anyone paging me at 2 AM. The cold-start tradeoffs I'd revisit today.

API GWLambdaSQSDynamoDB
Write-up coming soon
NashTech Global2016 → 2017 · ~5 min read

🛡️ KYC for banking & insurance, the boring-but-correct way

Why "boring" is the highest praise you can give a KYC system, and the patterns I borrowed from UBS / Manulife / Prudential to keep one.

JavaComplianceBanking
Write-up coming soon
🆕 2026 hobby · long read
zevmon.ca · solo2026 → today · ~10 min read

💸 ZevMon — a local-first money app across web, iOS & Android

One schema, three clients, zero vendor lock-in: SwiftUI/GRDB on iOS, Compose/Room on Android, Vite on the web, Express + SQLite API in the middle. Bank PDFs are imported from Gmail and parsed by Claude Sonnet 4 with my own key, deduped by content hash, synced via Drive + Firestore with last-writer-wins. Plus a Telegram bot that talks to my finances.

SwiftUIComposeTypeScriptClaudeGmail APITelegram
Read the build log →
vinhnx.ca2026 · ~4 min read

🧪 This site, in public

CloudFront + S3 + Lambda + DynamoDB, all Terraformed. RAG chat with voice I/O, admin analytics down to per-project attention, a posts CMS, Telegram-backed contact form. Built so I can show how I build.

TerraformLambdaRAGCloudFront
Write the meta-post →

Notes

Long-form writing on what I'm building, learning, and shipping. Filter by category below.

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