Mobile Engineer - SDKs (Contract - US, LATAM, Spain)

Job Description

About Crossmint 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! Location US, Latin America, or Spain. Candidates must confirm they are able to work in alignment with ET/EST business hours. Type of employment Contractor role (20-40 hours per week). Initial 3-month engagement, renewable. Potential to convert into full-time employment. Compensation Per-hour setting for the contract duration. Responsibilities As a Mobile SDK Engineer at Crossmint, you will be responsible for: Designing and architecting mobile SDKs from the ground up. Building SDKs for core features such as authentication, smart wallets, and payments. Collaborating with cross-functional teams to understand the business needs and translate them into mobile SDK solutions. Documenting your architecture and design choices clearly and concisely. Owning your projects end to end: from initial concept through to deployment and support. Mentoring other team members as we grow the mobile engineering team. About you To thrive in this role, you should possess the following qualifications: Professional Experience: 5+ years of experience in mobile software development in native iOS (Swift) and Android (Java or Kotlin) At least 1+ year specifically in mobile SDK development (not just mobile app development). Excellent Communication Skills: Demonstrate excellent written and spoken English. Educational Background: Hold a Bachelor’s degree in Computer Science or a related field, or equivalent knowledge and skills with industry experience. Preferred Experience We highly value candidates with the following experiences: Experience with blockchain or Web3 technologies is a plus, particularly in relation to wallets or payment systems. Provable experience shipping high quality code. Experience working on a team and references to back it. React Native or Flutter experience is nice to have.