Ruben Castro

Senior Software Engineer @ Phantom | Money Movement, Fiat On-Ramps & Stablecoins | Ex-MoonPay & Onfido | Fintech, Crypto, Payments, KYC

Maia, Porto, Portugal

About

I’m a Senior Software Engineer focused on fintech, crypto payments and high-scale money movement systems. I currently work at Phantom as part of the Money Movement team, contributing to critical platform products such as fiat on-ramp, Progressive KYC and Phantom Cash, Phantom’s stablecoin product. My work involves building reliable backend systems using technologies such as NestJS, Kafka, AWS, Redis and CockroachDB. Previously, at MoonPay, I worked on global fiat payment infrastructure powering crypto purchases, payouts, routing, availability, settlement and reconciliation flows. I contributed to systems involving ACH, SEPA Instant, PayPal, Venmo, Interac, Plaid, Modern Treasury and Cross River Bank. Before that, at Onfido, I worked on identity verification and KYC systems used in regulated environments. I’m particularly interested in backend engineering, distributed systems, payment infrastructure, stablecoins, KYC, risk, compliance and building reliable financial products at scale.

Experience

  • Senior Software Engineer - Money Movement at Phantom
    Apr 2026 - Present · 3 mos

    * Member of the Money Movement team, working on some of Phantom’s most critical financial infrastructure. * Contributing to fiat on-ramp, Progressive KYC and Phantom Cash, Phantom’s stablecoin product. * Building backend services for money movement, transaction processing, user verification and financial product flows. * Working with NestJS, Kafka, AWS, Redis and CockroachDB. * Collaborating closely with Product, Compliance and Infrastructure teams on secure and reliable financial systems.

  • Senior Software Engineer - Payments at MoonPay
    Jan 2024 - Apr 2026 · 2 yrs 4 mos

    * Built and maintained global fiat payment infrastructure powering crypto purchases, sales and payouts. * Worked on payment routing, payment availability, settlement, reconciliation and transaction lifecycle services. * Delivered and supported payment capabilities across ACH, SEPA Instant, PayPal, Venmo and Interac. * Integrated with financial infrastructure partners such as Plaid, Modern Treasury and Cross River Bank. * Collaborated with Product, Risk, Compliance and Operations teams in a highly regulated fintech environment. * Participated in production support, on-call rotations and incident management using incident.io.

  • Senior Software Engineer at Onfido
    Dec 2021 - Jan 2024 · 2 yrs 2 mos

  • Senior Software Engineer at DefinedCrowd
    May 2020 - Nov 2021 · 1 yr 7 mos

  • Senior Software Engineer at Hostelworld Group
    Aug 2019 - May 2020 · 10 mos