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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Backend Engineer - **Company:** SPD Technology - **Location:** Spain (Remote available) - **Contract:** Permanent contract - **Skills:** Cloud Computing, Continuous Integration, Relational Databases, Payment Systems, PostgreSQL, Node.Js, Payment Service Provider, PCI Data Security Standards, Shopify, Software Engineering, TypeScript, WooCommerce, Transaction Processing (Computing), State Machines, Backend, Magento, Stripe, Iframes, Event Sourcing, NestJS, Webhooks, Api Management, Golang - **Published:** October 3, 2026 - **Apply:** https://www.adzuna.es/details/5908182667 ## About the Role * 6+ years of professional software engineering experience. * At least 3 years of hands-on experience with payment systems or payment processing. * Strong backend engineering experience with Go, TypeScript, and Node.js. * Direct experience owning production payment flows rather than only performing basic payment API integrations. * Experience integrating payment processors, gateways, or acquirers such as Stripe, Adyen, Braintree, Checkout.com, Worldpay, Fiserv, or similar providers. * Strong understanding of the card payment lifecycle, including authorization, capture, settlement, refunds, chargebacks, and disputes. * Understanding of bank payment rails and preferably ACH/NACHA concepts, including returns and transaction timing. * Experience with payment reconciliation and settlement. * Strong understanding of webhooks, retries, idempotency, asynchronous processing, and distributed-system failure scenarios. * Experience designing relational data models for transaction-heavy systems. * Understanding of PCI DSS and payment-security patterns such as tokenization and isolation of sensitive payment data. * Strong attention to correctness and edge cases, especially in financial systems. * Fluency with modern AI-assisted development tooling. * Strong English communication skills and confidence working directly with a US-based team. * Ability to work with 4-6 hours of daily overlap with US Central Time. Bonus points * Experience with platform, marketplace, or facilitator models (split payments, sub-merchant onboarding, multi-party flows). * Experience with payouts and disbursement rails, including bank-account collection, verification, and payout status handling. * Experience with fraud and risk tooling, and bank-account validation services. * Experience with e-commerce plugin or SDK development (WooCommerce, Shopify, Magento). * Knowledge of multi-currency, cross-border, or alternative payment methods. * Experience with event sourcing applied to financial state, and double-entry ledger design. ## Description As a Senior Backend Engineer you will join a product team building payment infrastructure for merchants and partner platforms. The platform enables businesses to accept payments, manage payouts, process card and bank transactions, and handle payment-related operations without relying on multiple disconnected providers. The engineering challenges go far beyond basic payment integrations. The platform handles payment orchestration, transaction processing, settlement and reconciliation, payouts, fraud and KYC integrations, and complex failure scenarios across systems that the team does not fully control. This role is a strong fit for an engineer who understands how money actually moves through payment systems and is comfortable owning critical backend flows end to end. Tech Stack Go, TypeScript, Node.js / NestJS, PostgreSQL, Event-driven backend services, Webhooks and asynchronous processing, Payment processor and acquirer integrations, Containerized cloud infrastructure, CI/CD Work environment Full-time, remote. Daily collaboration with a US-based team (4-6 hours of overlap with US Central Time is required) As a qualified expert You will * Own end-to-end payment flows in TypeScript/NestJS services: authorization, capture, void, refund, dispute handling, and payout initiation and confirmation. * Build and maintain acquirer and processor integrations, keeping the platform acquirer-agnostic behind clean internal abstractions. * Design embedded and hosted checkout experiences (hosted fields, iframes, tokenization) that keep sensitive cardholder and bank data out of internal systems and minimize PCI scope. * Implement fee calculation and rate logic, including tiers, interchange-plus, flat structures, rounding rules, special rates, and edge cases. * Build the reconciliation and settlement layer to match processor reports and settlement files against internal records and surface breaks. * Design event handling incorporating idempotency keys, out-of-order and duplicate webhooks, retries with backoff, and state machines. * Integrate fraud, bank-account verification, and KYC providers, tuning decisioning against real outcomes. * Handle ACH mechanics including submission windows, returns, return codes, NOCs, and retry rules. * Ensure correctness in the domain, maintaining complete audit trails and producing reconciliation evidence. * Act as the team's payments expert, advising product on rail capabilities and reviewing payment-adjacent code., Join the team of experts who create custom, cutting-edge tech solutions for world-renowned businesses, fueling clients growth. Unleash your potential, tackle new challenges, and be part of a team that values your skills and contributions. Focus on long-term impact and building tailored, long-lasting partnerships with our clients. Experience an agile and flexible working environment Work fully remote around the globe, or in a hybrid work model from our office hubs which are equipped with everything needed for comfortable work. Enjoy a flexible working schedule and create work and rest balance for yourself. Empower yourself with a stable workload and a stable income, focusing on lasting cooperation and high-performance culture. Embrace the opportunity for personal and professional growth Take advantage of performance review and career path. Elevate your skills with mentorship program, personal development plan, and individual learnings through the corporate library, public speaking support, and more. Feel cared about Be among like-minded people and feel supported with collaboration, open communication and mutual respect. Join company-wide tech and cultural events, and contribute to meaningful CSR initiatives that resonate with your values. Interview steps 1. Interview with Recruiter 2. Technical Interview 3. 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