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# Sr. Backend Engineer II - US Stocks

- **Company:** AJAIB 495 LLC
- **Location:** United States (Remote available)
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Java (Programming Language), Application Programming Interfaces (APIs), Amazon Web Services, Code Review, Continuous Integration, Financial Information EXchange, NoSQL, Query Optimization, Redis, WebSocket, Caching, Backend, Event Driven Architecture, Information Technology, Apache Kafka, Api Design, Microservices
- **Published:** November 13, 2026
- **Apply:** https://arc.dev/remote-jobs/j/redirect/pyvtzybfdu

## About the Role

* Education: Bachelor's degree in Computer Science or equivalent practical experience
 * Experience: 5+ years of professional backend engineering, with a track record of owning production services under high traffic
 * Languages: Strong in Java, Go or another modern backend language
 * System Design: Solid understanding of microservices, REST/gRPC APIs, event-driven design, and reliability and observability practices
 * Data & Messaging: Hands-on with relational and NoSQL databases (query tuning), caching (Redis) and messaging (Kafka)
 * Infrastructure: Experience running services on cloud platforms (GCP or AWS), with containers and CI/CD
 * Mindset & Domain: Ownership mindset and clear communication. Experience in brokerage, trading, payments, cross-border money movement or another regulated environment is a strong plus
 * Deep understanding of modern API-first brokerage platforms (e.g., Alpaca, Interactive Brokers) or crypto exchanges, including WebSocket streaming for market data and FIX protocol fundamentals

## Description

As a Sr. Backend Engineer II in the US Stocks team, you own backend services for trading US stocks from design to production: order flow to our brokerage partners, balances and currency conversion, market data, portfolio and corporate actions. You take on larger and more complex features, make sound design decisions under real traffic, and mentor engineers around you.

 * Design, build and run scalable, secure backend services and APIs for trading, funding, market data and portfolio features
 * Own larger features and services end to end, including monitoring, alerting and on-call follow-up
 * Design for correctness first: accurate money and quantity handling, idempotent requests, safe retries and audit trails
 * Integrate with US brokerage and custody partners, and make those integrations resilient to outages, delays and duplicate or out-of-order messages
 * Build and improve reconciliation between our records and our partners' records, and drive root-cause fixes for mismatches
 * Handle US-specific events correctly, such as market hours, dividends, stock splits and settlement timing
 * Keep services fast and stable at US market open and during volatile days, and plan capacity ahead of known events
 * Lead design reviews and give thoughtful code reviews
 * Investigate production incidents, run root cause analysis and ship lasting fixes
 * Mentor mid-level engineers and share knowledge within the team
 * Design resilient, low-latency order routing logic to manage execution across multiple Liquidity Providers (LPs) and venues, handling rate limits, partial fills, and complex order lifecycles
 * Proactively identify systemic risks across the US Stocks domain and propose architectural improvements, acting as a technical bridge to Staff engineers