📍 Remote | 💰 USD $80–100K / year | 🏖 32 days | 💼 Full-time (B2B contractor) | ⏱ Start: ASAP (notice periods respected)

Koinly helps people calculate crypto taxes and track assets. Our backend processes billions of transactions across 1000+ integrations, powering tax reports for 1.5M+ users.

We’re remote-first, async-first, and operate with a small engineering team where individual ownership matters.

Why this role exists <
We have product–market fit in a high-scale, messy-data domain. The work is not “build another CRUD screen”. It’s making Ruby/Rails services stay fast and correct when you throw massive datasets, CSV imports, and inconsistent external data at them.

If you get motivated by:
⚡ shaving milliseconds off slow queries
📦 turning hour-long CSV imports into minutes
🧠 simplifying systems without making them fragile
…you’ll like this role.

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🛠 What you’ll do
• Own backend services end-to-end: design, build, refactor, optimize.
• Make huge datasets fast, reliable, and cost-efficient.
• Debug production issues across code + data + integrations.
• Write clean, tested, maintainable code that holds up under load.
• Drive performance work: query tuning, indexing, execution plans, caching, background jobs.
• Join a lightweight on-call rotation (few incidents; careful releases are the norm).

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✅ Must-haves
• 6+ years professional Ruby experience (Rails expected).
• Strong SQL and performance tuning skills (query plans, indexing, diagnosing slow queries).
• Proven production debugging + ownership through resolution.
• Experience scaling backend systems (APIs, background jobs, services/microservices).
• High engineering standards: clarity, tests, CI/CD hygiene, pragmatic refactoring.
• Comfortable working async: clear written updates, low meeting dependency, high autonomy.

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✨ Bonus points
• High-volume CSV/data ingestion or pipeline work (idempotency, dedupe, retries, partial failures).
• Ruby profiling/performance work (hotspots, memory, slow paths).
• Fintech/regulated domain experience or crypto familiarity.
• Side projects that show you enjoy hard technical puzzles.

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🧭 How we work (async-first, remote-first)
• Minimal meetings, default to writing + deep work.
• High ownership, high trust, direct feedback.
• Engineering-led culture: maintainability and reliability come before speed.

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🚫 Probably not a fit if
• Your Rails work is mostly UI/features with light SQL and little performance ownership.
• You prefer frequent meetings and highly structured processes over async autonomy.
• You dislike ambiguity and inconsistent “messy” data.

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🔎 Note
Due to the nature of our business and external requirements, we run background checks as a condition of employment.