Sr. Backend Engineer II - US Stocks

Founded to transform retail finance, Ajaib Group is an Indonesian fintech unicorn breaking barriers to financial access. Having recently secured a $270M Series C—the single largest funding round in Southeast Asia over the past four years—we are backed by premier global investors including Y Combinator, Ribbit Capital, SoftBank, and SBI Holdings.  

To build world-class products, we assemble world-class talent. Supported by our fully remote work arrangement, our team spans Eastern Europe, the Middle East, India, and Southeast Asia, allowing you to work with brilliant engineers and builders from around the globe from wherever you are. We operate with an impact-driven purpose where everyone is the owner of our customers' satisfaction. Driven by a growth mindset and a fierce will to win, we refuse to settle and constantly push engineering boundaries.

Role Overview

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.

Requirements

• 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.

Benefits

• Performance Bonus - Get rewarded for the impact you make
• Private Insurance - Comprehensive health coverage for you 
• Paid Time Off - Take the time you need to recharge and come back stronger
• Learning & Development - Company-sponsored training, courses, and professional certifications
• Hybrid Work Arrangement - Enjoy the flexibility of working both remotely and from the office
• Career Growth - Work closely with experienced leaders and take on meaningful ownership as we scale
• Employee Perks - Enjoy exclusive discounts, partnerships, and lifestyle perks
• Collaborative & High-Ownership Culture - Work with smart, driven people in cross-functional teams, take ownership, and make a meaningful impact for our users.