QA Engineer - APIs & SDKs (Contract - US, LATAM, Spain)
If you are interested, please apply here
Stablecoins and blockchains are upgrading the world’s financial system — and Crossmint lets companies harness their power with ease.
Crossmint is a one-stop-shop developer platform for building modern financial applications, from the next generation of fintechs to applications that leverage AI agent–driven commerce.
With just a few lines of code, developers can integrate programmable wallets, stablecoin payments, tokenization, on/off ramps, compliance, and agentic commerce tools — all from a single vendor, without the need for a large team of blockchain engineers.
From companies like MoneyGram and Visa to entire nation states, our more than 40,000 clients use Crossmint to launch new financial products, tokenize assets, and build applications for agentic commerce — all on fully managed infrastructure across 50+ chains.
If you want to help build the backbone of programmable finance and agentic systems, we’d love to work with you!
US, Latin America, or Spain. Candidates must confirm they are able to work in alignment with ET/EST business hours.
Contractor role (20-40 hours per week).
Initial 3-month engagement, renewable.
Potential to convert into full-time employment.
Per-hour setting for the contract duration.
We’re looking for a Technical QA Engineer to join our team building APIs and SDKs for crypto infrastructure. You’ll operate at the intersection of quality assurance and technical support engineering, ensuring our APIs and SDKs are robust, reliable, and intuitive for developers.
Design comprehensive test plans and cases based on product requirements.
Execute manual and automated tests across multiple platforms and edge cases.
Validate end-to-end functionality across Wallets, Payments, and Minting products.
Document results and proactively communicate issues to engineering teams.
Technical Support Engineering
Evaluate developer experience for API and SDK integrations.
Act as a technical escalation point for complex or hard-to-reproduce issues.
Reproduce, debug, and analyze issues; provide detailed technical insights to accelerate fixes.
Build and maintain demo applications for testing API/SDK functionality.
Contribute to internal tools and scripts that improve QA and debugging workflows.
Essential: Strong knowledge of REST APIs and SDKs.
Proficiency in one or more modern programming languages (JavaScript/TypeScript, Python, or similar).
Ability to build small apps or prototypes to test integrations.
Big bonus: experience with React or React Native.
Quality Assurance Background
Proven experience writing test plans, test cases, and executing both manual and automated tests.
Familiar with QA methodologies and frameworks (e.g., Postman/Bruno/cURL, Jest, Cypress, etc.).
Skilled at debugging and troubleshooting hard-to-reproduce issues.
Clear and effective communicator, especially when relaying technical details to engineering teams.
Experience with blockchain technologies, crypto wallets, or payment APIs.
Understanding of developer experience best practices.
Results and delivery: Ship high quality work fast.
Build for the long term: Build scalable, secure, and reliable solutions. Use AI.
Extreme Ownership: Be an effective Directly Responsible Individual (DRI). Be proactive.
Be a team player: Be an effective and kind colleague providing credible challenge. Be present and reliable.
Talent research indicates that women are often less inclined than men to apply for a role unless they have experience in 100% of the listed skills. However, this list is only a guide. We welcome your application even if you feel you meet around 75% of the requirements. At Crossmint, we believe skills can be learned, and diversity makes us stronger.
We work to foster a respectful environment where each person can be their authentic self, free from harassment, racism, and any form of discrimination. We proudly uphold our commitment to diversity and inclusion as an equal opportunity employer, and this policy applies to all employment practices within our organization.
Please note that Crossmint never conducts AI-based interviews, and all of our processes include an initial video call with a team member. Crossmint will not request your personal identification documents or any payment at any point during your interview process. Please stay vigilant about potential fraud. If you receive an email that claims to be from Crossmint but ends with any domain other than @crossmint.com, @crossmint.io or @paella.dev, it is not from us. We own these three domains listed before, and they are the only legitimate ones.
Please let our Talent Team know if you need any assistance completing any forms, or participating in the process.
If you are interested, please apply here
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