QA Engineer

Ostium is on a simple mission: make it possible for anyone with a digital wallet to trade stocks, commodities, currencies, and crypto with full transparency. No brokers, no freezes, no hidden spreads. We’re replacing the opaque, offshore brokerage model with a transparent, permissionless trading stack built onchain. Every trade, deposit, and withdrawal is verifiable through open, auditable code. We’ve raised $27.9M+ from General Catalyst, Jump, LocalGlobe, Susquehanna (SIG), GSR, Alliance DAO, Soma Capital, Balaji Srinivasan, Meltem Demirors, and others.

We're hiring a QA engineer (2–4 years experience) who understands DeFi. You'll own quality across our web and mobile frontends, not just running test cases, but thinking like a user who has real money on the line. You need to understand how perpetual trading works, what leverage means, how wallets connect, how transactions flow and where all of that can break.

• Own quality across web and mobile frontends

• Think like a real user with money on the line — hunt for edge cases, broken flows, and UX friction

• Write and maintain automated test suites for the web app (Cypress, Playwright, or similar)

• Test DeFi-specific flows — wallet connections, approvals, order types, transaction states, network switching

• File detailed, actionable bug reports with reproduction steps engineers can immediately act on

• Use browser dev tools and logs to investigate issues beyond surface-level symptoms

• Work with engineering to verify fixes, catch regressions, and validate releases before they ship

• Help build and improve CI-integrated test pipelines over time​​​​​​​​​​​​​​​​

• Solid experience testing web and mobile applications.

• Familiar with DeFi primitives like wallets, approvals, order types, on-chain vs off-chain flows, network switching, transaction states.

• You should be able to look at a trading interface and intuitively know what edge cases to hunt for.

• Experience with automation testing on web apps (Cypress, Playwright, or similar), writing and maintaining test suites, not just manual passes.

• Comfortable reading logs, using browser dev tools, and filing bugs that engineers can actually act on.

• Experience testing across multiple chains or L2s.

• Familiarity with mobile testing frameworks (Detox, Appium).

• Basic scripting ability (JS/TS or Python).

• Experience with CI-integrated test pipelines.

• Competitive compensation package

• Opportunity to work with cutting-edge blockchain technology

• Collaborative environment with highly skilled team members

• Flexible work arrangements

• Professional development opportunities

You're the person who finds the bug everyone else missed because you actually used the product like a real user would. You take ownership of quality and not just flagging issues but following them through to resolution. You're curious about how things work under the hood, even if you're not writing the code. High agency while obsessed with getting the details right.

If this sounds like you, reach out.

NYC Pay Transparency Disclosure:
Salary Range: $100,000 to $250,000 annually plus benefits.

This salary range is based on the current available market data, and represents the expected salary range for this role. Ostium has minimal hierarchy and few titles, but has broad ranges of experience represented within roles. Should you have compensation expectations that exceed these bands, we'd love to hear from you and would welcome you to reach out to further discuss.

Commitment to Equal Opportunity
Ostium is committed to creating a culture of inclusion and belonging, and we are proud to be an equal opportunity employer. We believe it is our collective responsibility to uphold these values and encourage candidates from all backgrounds to join us in our mission. All qualified applicants will be treated with respect and receive equal consideration for employment without regard to race, color, creed, religion, sex, gender identity, sexual orientation, national origin, disability, uniform service, veteran status, age, or any other protected characteristic per federal, state, or local law. If you are passionate about what you do and want to use your talents to support our mission and values, we’d love to hear from you.