Location: This role can be done remotely
KORE1, a nationwide provider of staffing and recruiting solutions, has an immediate opening for a Senior Payments Engineer Build & Scale Billing, Subscriptions & APIs (Node.js, TypeScript, REST APIs) that is fully remote.
This role focuses on building and maintaining reliable, scalable payment and billing systems that directly impact revenue and the customer experience. You will take ownership of the full payment lifecycle, from transaction processing to subscription management and financial reconciliation, ensuring accuracy, resilience, and security across all billing workflows. This includes working within a semi-complex subscription model (tiers, credits, usage-based billing, upgrades/downgrades, promotions/discounts, and affiliate/referral considerations).
This is a high-impact position requiring hands-on experience with real-world payment systems and the ability to design solutions that handle complexity, edge cases, and scale. You will play a key role in stabilizing an existing platform in the near term while driving scalability and future-state improvements over time.
What You'll Do
- Own and manage the full payment ecosystem, including primary processors and alternative payment methods (including future expansion into crypto integrations such as Solana)
- Design and maintain subscription lifecycle logic, including activation, upgrades, downgrades, cancellations, recovery flows, and edge-case handling
- Build robust webhook processing systems with strong guarantees around idempotency, ordering, and retry handling
- Develop reconciliation processes across multiple timeframes, incorporating audit trails and anomaly detection (both integrating with existing systems and enhancing where needed)
Implement workflows for refunds, chargebacks, and dispute resolution - Ensure system reliability through comprehensive test coverage, including integration and end-to-end testing of payment flows
- Design and enforce fraud detection mechanisms, tax/VAT considerations, and rate-limiting strategies (full ownership expected)
- Maintain and enhance payment security practices, including compliance with industry standards
- Identify and resolve UI-level payment issues and edge case errors impacting user experience
- Leverage AI tools where appropriate to improve development velocity, testing, and system design efficiency
Work style:
- Small, high-ownership team - you'll own entire systems, not just tickets
- Pre-commit validation runs 19,600+ tests on every commit
- Self-hosted infrastructure (DigitalOcean), not serverless
- Staging -> production deployment flow with manual production gate
What We're Looking For
- Bachelor's degree from a competitive university OR a proven track record of delivering high-impact, real-world products at meaningful scale
- Proven experience OWNING, building and deploying payment or billing systems in production environments
- Strong understanding of the full payment lifecycle, including authorization, capture, settlement, refunds, and reconciliation
- Deep knowledge of subscription-based systems and common failure scenarios (e.g., webhook race conditions, retries, partial failures)
- Experience designing financial reconciliation systems, including ledger patterns and audit logging
- Strong backend development skills using Node.js and TypeScript
- Experience working with asynchronous processing systems and background job workflows (or ability to ramp quickly)
- Ability to independently own and deliver complex, high-risk systems
- Experience leveraging AI tools in your workflow (e.g., development, testing, system design, debugging, or documentation), including clear examples of tools used, in which roles, and for what functions
- If applicable, ability to articulate the extent to which AI-assisted coding has been utilized (e.g., percentage of code or workflow supported by AI tools)
Required Experience (Non-Negotiable)
- Hands-on experience working with a payment gateway system in a production environment (e.g., Stripe, Braintree, Adyen, PayPal, Authorize.net, or similar), including APIs related to transactions, subscriptions, and customer data management; Authorize.net experience is strongly preferred and will be prioritized
- Experience building a payment system end-to-end that processes real transactions from real users
Nice to Have
- Experience integrating cryptocurrency payment systems (e.g., Solana, Ethereum, Polygon)
- Familiarity with PCI compliance standards and secure payment handling practices
- Experience with modern backend frameworks such as NestJS
What we value:
- Ship working software over perfect architecture
- Own your domain end-to-end (design -> implement -> deploy -> monitor)
- Write tests that catch real bugs, not tests for coverage numbers
- Communicate clearly when things break - incidents happen, silence is the problem
Technology Stack
- Authorize.net and related payment APIs
- Web3 libraries for crypto payments
- Node.js / TypeScript
- NestJS
- PostgreSQL, Redis
- Temporal or similar workflow orchestration tools
With all applications, please provide the following:
- Details on any AI tools/platforms you have used in your work, including which companies/roles you used them in and for what functions (e.g., development, testing, system design, debugging, documentation)
- Proof of work: Please share a couple of example links to your work (live websites or systems in production) that you can confidently say you owned end-to-end.
- Scale: For the examples above, provide a rough metric of how much traffic, users, or usage they experienced (e.g., number of users, transactions, or system volume).
- AI/LLM usage: Provide a rough estimate of what percentage of the work on those examples was done with the help of LLMs or coding agents.
Compensation depends on experience but is typically $120-140K
Note: This engagement does not include a benefits package.
ABOUT KORE1
Specializing in professional and technical recruiting, KORE1 is committed to supporting top IT, Engineering, Creative, Scientific, Accounting and Finance professionals in their career paths. We build deep relationships with leading companies, connecting them to exceptional talent every day. With extensive industry expertise and unmatched opportunities, our goal is to provide a unique experience for our contractors and consultants as they prepare for their next role. We are passionate about matching the right people with the right companies.
Kore1 provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, color, religion, sex, national origin, age, disability or genetics. In addition to federal law requirements, Kore1 complies with applicable state and local laws governing nondiscrimination in employment in every location in which the company has facilities. This policy applies to all terms and conditions of employment, including recruiting, hiring, placement, promotion, termination, layoff, recall, transfer, leaves of absence, compensation and training. Kore1 expressly prohibits any form of workplace harassment based on race, color, religion, gender, sexual orientation, gender identity or expression, national origin, age, genetic information, disability, or veteran status. Improper interference with the ability of Kore1's employees to perform their job duties may result in discipline up to and including discharge.
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