~/shahbaz%whoami
Software Engineer 2 @ Drivetrain.ai

Shahbaz Hasan.
Raja

Backend engineer building event-driven systems and AI infra.

As a seasoned software engineer, I design and develop scalable backends that power event-driven systems, multi-tenant SaaS platforms, and cutting-edge AI infrastructure. At Drivetrain.ai, I'm currently leading the deployment of a Role-Based Access Control (RBAC) audit logging system, a connector-sync scheduler, and Heimdall – an internal MCP Gateway, as well as Maglev – an autonomous triage agent built on the Claude Code and MCP. My experience spans notable companies like WeWork India and LetsTransport, where I honed my skills in building robust software solutions.

GitHubLinkedInLCLeetCode</>GeeksforGeeksMedium[email protected]

01 / TRACK_RECORD

Where I've shipped.

Full-stack backend work across fintech, proptech, and logistics — shipping systems that 100K+ people touch every day.

  1. Drivetrain.ai

    Remote

    Software Engineer - 2

    ·Oct 2025 — Present

    • AI Infrastructure — Maglev, Heimdall, RAG Pipeline

      Built Drivetrain's applied-AI surface end-to-end. Maglev - a fleet of 14 cron-scheduled agents (Claude Code + MCPs) that triage Linear bugs, nudge stale reviews, scan recurring errors, and author bug-fix PRs end-to-end with a Playwright smoke-test gate. Heimdall — a stateless MCP gateway proxying 5 internal services with TTL caching and fault isolation, collapsing N point-to-point integrations into one queryable surface. RAG Pipeline — a Gitbook-backed retrieval system watching customer Slack channels, drafting humanized answers with confidence scoring, context-aware dedup, and thread-aware follow-up handling.

      Claude CodeMCPRAGPlaywrightFastAPIPython

    • Platform & Backend — RBAC, Connector Sync, Metric Cloning

      Shipped the multi-tenant platform plumbing for 500+ tenants and 4K+ users. RBAC Audit Logging — end-to-end permission tracking across 13 resource types with batch DB writes, filterable changelog APIs, CSV export, and a new Security Auditor role with member-scoped read-only access. Connector Sync Scheduling — multi-schedule CRUD APIs with server-side cron generation (daily/weekly/monthly with ordinal support), row-level locking for concurrency safety, and a per-tier toll-gate that directly enabled a premium monetization path. Cross-Version Metric Cloning — transitive dependency resolution,regex-safe formula rewriting across version-specific BigQuery references, dual-context RBAC validation, and atomic session switching for safely reusing 500K+ planning variables.

      JavaSpring BootPostgreSQLRBACMulti-tenant

  2. WeWork India

    Bengaluru

    Software Development Engineer - 2 (Backend)

    ·Apr 2024 — Aug 2025

    • SpaceOps

      Engineered and deployed the SpaceOps tool saving INR 1 Cr/year in licensing, adopted by 300 internal users across 70+ centres. Streamlined a critical API using concurrent execution with Promises, DB indexing, and hashmap optimizations — response time dropped from 4s to 800ms.

      NestJSPostgresPerformance

    • Locations & F&B Modules

      Designed a scalable Locations module using Google Maps, PostgreSQL, Redis & OpenSearch — supporting 70+ centers and 100K+ users with write-through caching. Built a community-café ordering system with UMS SSO and Server-Sent Events for real-time order tracking, serving 3K daily users.

      NestJSRedisOpenSearchSSEGoogle Maps

    • Help & Support Module

      Engineered a GenAI LLM-based ticket classifier (OpenAI API & prompt engineering), boosting accuracy to 85% and cutting triage time by 40%. Implemented a BullMQ-driven webhook ingestion pipeline processing 10K+ Salesforce updates/month.

      OpenAIBullMQSalesforce

  3. LetsTransport

    Bengaluru

    Software Development Engineer - 1 (Backend)

    ·Jul 2022 — Apr 2024

    • Trip Lifecycle & API Migration

      Owned trip management APIs (start, end, cancel) — the core logistics workflow for driver-partner operations. Refactored and migrated 8 endpoints across microservices using the Template Design Pattern, cutting response time by 50%. Hardened P0 business APIs with middleware-level validations ensuring tenant-scoped data access.

      Node.jsTypeScriptDesign Patterns

    • Bidding, Rate Card & Margin Config

      Built a partner bidding system with per-lane controlled rollouts and CDE visibility, a Rate Card module for digitizing commercial contracts, and a Margin Config system enabling senior leadership to set target gross margins at client-lane-vehicle granularity — directly reducing revenue leakage.

      Node.jsPostgres

    • Infrastructure & Data Pipelines

      Designed a WhatsApp chatbot via Meta Webhooks for order lifecycle management. Migrated Redis to Sentinel for HA, secrets to GCP Secret Manager, decoupled FE/BE pipelines (30→5 min builds), and built Airflow DAGs warehousing 20+ MongoDB collections into PostgreSQL for BI.

      AirflowRedis SentinelGCPMeta Webhooks

02 / SHIPPED

Stuff I've built for fun.

Things I've built outside of work — mostly to learn something new or scratch an itch.

Personal Developer Platform

Custom OAuth 2.0 Authorization Server + AI-powered portfolio API — built from the protocol spec up, owning the full auth and content lifecycle.

  • ▸ RFC-compliant OAuth 2.0 AS: DCR (RFC 7591), PKCE S256 (RFC 6749), revocation (RFC 7009), discovery (RFC 8414)
  • ▸ Salted ticket JWTs, single-use auth codes, two-layer ACL — security by spec, not by framework default
  • ▸ BullMQ repeatable jobs: LeetCode stats hourly, GitHub stats 6-hourly, with idempotency checks
NestJSTypeScriptPostgreSQLRedisOAuth 2.0PKCEBullMQTypeORM
View on GitHub

YouTube.ai

Video-intelligence backend: map-reduce summarization, distributed Whisper transcription, HLS streaming.

  • ▸ Outbox Pattern for exactly-once Kafka publishing
  • ▸ Map-reduce summarization of long transcripts
  • ▸ Bloom Filters for transcript dedup
NestJSFastAPIKafkaPostgreSQLRedisOpenAIOpenSearchCelery
View on GitHub

03 / SOURCE_CODE

What the work actually looks like.

Two slices from live repos — the matching-engine while loop and the transactional outbox pattern. Not screenshots, actual source.

Price-time priority with partial fills

javaview on GitHub

Core of the exchange — walks incoming orders against the counter book, trades at the maker price, restores time priority for partially filled counters.

public MatchResult matchOrder(Order incoming) {
    if (incoming.getRemaining().compareTo(BigDecimal.ZERO) <= 0) {
        return MatchResult.empty(incoming);
    }

    // BUY matches against SELL book; SELL matches against BUY.
    OrderSide counterSide = incoming.getSide() == OrderSide.BUY
            ? OrderSide.SELL : OrderSide.BUY;

    List<Order> toUpdate = new ArrayList<>();
    List<Trade> trades = new ArrayList<>();
    toUpdate.add(incoming);

    while (incoming.getRemaining().compareTo(BigDecimal.ZERO) > 0) {
        Order counter = book.pollBest(counterSide);
        if (counter == null) break;

        // Price compatibility: bid >= ask for BUY, ask <= bid for SELL.
        if (!priceMatch(incoming, counter.getPrice())) {
            book.addFirst(counter);   // restore time priority
            break;
        }

        BigDecimal qty   = incoming.getRemaining().min(counter.getRemaining());
        BigDecimal price = counter.getPrice();  // maker wins

        incoming.setRemaining(incoming.getRemaining().subtract(qty));
        counter.setRemaining(counter.getRemaining().subtract(qty));
        incoming.setStatus(incoming.getRemaining().signum() == 0
                ? OrderStatus.FILLED : OrderStatus.PARTIAL);
        counter.setStatus(counter.getRemaining().signum() == 0
                ? OrderStatus.FILLED : OrderStatus.PARTIAL);

        trades.add(buildTrade(incoming, counter, qty, price));
        toUpdate.add(counter);

        // Partial counter stays at the front of its price level.
        if (counter.getStatus() == OrderStatus.PARTIAL) {
            book.addFirst(counter);
        }
    }

    return new MatchResult(incoming, toUpdate, trades);
}

src/main/java/.../engine/MatchingEngine.java

04 / LOADOUT

Tools of the trade.

What I reach for day to day — not an exhaustive list, but the things I've actually shipped with.

Languages

  • Java
  • Python
  • C++
  • TypeScript
  • JavaScript

Frameworks & Libraries

  • Spring Boot
  • JPA / Hibernate
  • NestJS
  • FastAPI
  • Node.js

GenAI & AI Tooling

  • Claude Agent SDK
  • MCP
  • LangChain / LangGraph
  • OpenAI API
  • Prompt Engineering
  • RAG

Databases & Search

  • PostgreSQL
  • MongoDB
  • Redis
  • OpenSearch
  • Firebase

Infrastructure & Cloud

  • AWS
  • GCP
  • Apache Airflow
  • Docker

Messaging & Eventing

  • Kafka
  • BullMQ
  • Server-Sent Events

Design & Architecture

  • System Design
  • Microservices
  • Event-driven Architecture
  • API Design
  • DB Schema Design
  • OOP

05 / CREDENTIALS

Where I studied.

Jul 2018 — Jun 2022 · Bhubaneswar, India

Kalinga Institute of Industrial Technology.

Bachelor of Technology·Electronics & Computer Science·GPA 9.15 / 10

  • Ranked #1 in university on GeeksforGeeks

06 / FLAGS

Some things I'm proud of.

  • WeWork India

    Moonshot Award — WeWork Annual Awards

    Recognized for technical innovation in SpaceOps development.

  • WeWork India

    Most Innovative Engineer

    Named Most Innovative Engineer by the Head of Engineering at WeWork India.

  • LeetCode

    LeetCode Knight — 2000+ Rating

    Top 2% globally on LeetCode. 114 contests, ranked top 2.53% of 869K+ participants.

  • GeeksforGeeks

    #1 in University on GeeksforGeeks

    Ranked first at Kalinga Institute of Industrial Technology on GFG problem-solving.