Job Title: Senior Ruby Engineer

Company Name: Koinly

Job Details: $80-90kSQLRubySenior,and,Expert,levelRemote,from,US,,Canada,,Europe,,UKMore,information,about,location

Job Url: https://app.welcometothejungle.com/jobs/Btp_l-TR?theme=newly-added

Job Description: Role
Who you are
We’re looking for someone who excels at performance and data at scale, is comfortable with queries, indexes, and large imports, and is motivated to make systems faster and more efficient
Experience level: 6+ years of professional Ruby experience
6+ years of professional Ruby experience
Strong SQL skills, including performance tuning and complex queries
Strong problem-solving and debugging skills
Experience designing and scaling backend systems (microservices, APIs, background jobs)
Eagerness to work with a high-standard engineering team, CI/CD, and testing
A track record of taking full ownership of complex features or systems
Comfort with feedback loops and a high-ownership mindset
Desirable
Experience with high-volume CSV/data ingestion pipelines
Familiarity with performance profiling tools in Ruby
Background in DeFi, blockchain, or fintech
Side projects that show your love for technical puzzles

What the job involves
At Koinly, we’re hiring a Senior Ruby Developer to build and maintain scalable backend systems for over 2 million crypto investors. You’ll write high-performance Ruby/Rails code and continuously improve speed, reliability, and the overall user experience
We’re a profitable, bootstrapped, remote-first startup founded in 2018 with a strong product–market fit in the fast-growing crypto tax space. If you value autonomy, high engineering standards, and clear communication over heavy process and meetings, you’ll fit right in at Koinly
Type: Full-time (contractor - B2B)
Team size: 10 person engineering team
Main responsibilities: Design, optimize, and scale Ruby backend services handling billions of records, ensuring performance, reliability, and clean code at massive scale
We’ve reached product–market fit in a high-scale financial domain and now need to keep improving performance and reliability while shipping new features. This means tackling challenges in:
Data architecture: Handling billions of rows, large CSVs, and high-throughput APIs
Performance: Query tuning, caching, and background jobs
System design: Scaling Ruby services that process terabytes of data reliably
Own backend services end-to-end: design, build, and optimize
Handle massive datasets (billions of transactions) efficiently and reliably
Debug production issues across code, data, and infrastructure
Write clean, tested, maintainable Ruby at scale
Prioritize performance, clarity, and simplicity in code and systems
Participate occasionally in on-call rotation (rare issues due to strong testing)
Keep up with Ruby best practices and emerging tools
⚙️ Craftsmanship matters: we value deep thinking, well-structured systems, and clean code
💬 Async-first collaboration: clarity and autonomy come through written communication
Impact through ownership: engineers drive projects end to end
🌍 Remote: we trust people to work flexibly and deliver excellence from anywhere

Application process
Start date: ASAP

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Insights

-44% employee growth in 12 months

Glassdoor (2.2)

Trustpilot (4.6)

Company
Company benefits
💸 Workplace pension scheme
🌅 25 days holiday a year
💆 Power down week
👪 Parental leave
😷 Paid sick leave
💻 Choice of laptop and working equipment
🏢 CBD office, with hybrid and flexible work arrangements minimum 3 days in the office
🚀 Work within one of the most rapidly growing industries in the world
🎒 Perks, including Koinly swag
☕ Free drinks & snacks
🎉 Regular and fun team social events!

Our take

Trading cryptocurrencies has become a lucrative profession for many investors, but one that is difficult to remain compliant within. The nature of the assets leads to constant price fluctuations and trading of many cryptocurrencies spread across multiple wallets, and its decentralised nature makes this activity difficult to track and analyse for tax calculations.
Koinly provides a tax management platform for cryptocurrency traders, allowing users to import cryptocurrency transaction records directly from ledgers, and aggregate it all into a tax report. The platform also helps users to track their portfolios, ROI, and capital gains within a minimalist dashboard, helping them to identify how to reduce taxes for the next year.

Many different cryptocurrency platforms aim to help traders analyse markets and make smart investment decisions, but the complications of tax reporting for crypto remain untackled. Koinly has recognised this gap in the market, claiming that its platform helps reduce the amount of time and money it takes to produce a crypto earning tax report, whilst identifying tax issues and ultimately ensuring compliance.

Steph
Company Specialist at Welcome to the Jungle