# Senior Software Engineer, Payments

**Company:** [Order.co](https://hotfix.jobs/companies/orderco)
**Location:** Remote
**Role:** Backend Engineering
**Skills:** Ruby, Ruby on Rails, Postgres, SQL, REST APIs, GraphQL, Webhooks, AWS, CI/CD, Stripe, Lithic, Adyen, Marqeta, Braintree, Double-Entry Ledger Design
**Posted:** 2026-05-18

> Senior Software Engineer on the Payments team owning virtual card issuance, bank connections, accounting integrations, invoicing, and ACH/RTP rails. Must have deep expertise in Ruby on Rails, PostgreSQL, payment processors, and secure money-movement systems.

## Job Description

## Responsibilities

### Technical Execution & Code Ownership
- Independently design and implement complex, multi-part features from requirements to production
- Own subsystems, services, or critical components in the payments stack — for example, the internal financial ledger, the virtual-cards issuance and authorization lifecycle, bank connections, or the invoicing and auto-debit pipeline
- Write clean, maintainable, production-ready code with consistent test coverage — money-movement code paths are held to a high test bar
- Navigate existing codebases with architectural discernment — identify sound patterns to build upon, recognize technical debt, and use AI tooling as an accelerant while applying your own judgment on correctness, security, and alignment with the system's direction
- Debug production issues effectively; seek first to understand — investigate evidence and identify root causes rather than applying band-aids, especially in webhook, retry, and reconciliation paths

### Design & Architecture Contribution
- Participate actively in design reviews; your designs regularly influence team-level architecture decisions
- Propose sound technical designs that account for scalability, performance, and reliability trade-offs — and for payments-specific concerns like idempotency, exactly-once semantics, reconciliation between internal state and vendor reports, and clean separation between authorization and capture
- Identify risks before they become incidents — surface edge cases, data consistency concerns, and failure modes during planning (double-charge, double-credit, dropped webhook, out-of-order event scenarios)

### End-to-End Delivery & Ownership
- Scope and estimate work accurately; break down epics into deliverable, independently reviewable units
- Deliver features end-to-end, including rollout coordination and post-release monitoring using feature-flagging, dark-launching, reconciling, and dashboards
- Communicate risks and blockers early
- Review stories critically before committing: ensure they're appropriately broken down and that dependencies are well understood by the team

### Mentorship & Technical Leadership
- Mentor junior and mid-level engineers through code reviews, pairing, and direct feedback
- Provide high-quality, substantive code reviews — lead with humility, treat the author as a teammate, and catch what AI misses
- Teach best practices; your presence raises the quality of code around you

### Technical Influence
- Influence technical decisions through credibility, not just seniority
- Drive improvements in team practices — testing patterns, observability for money-movement flows, code organization, and the bar for test coverage in code paths that move real funds
- Champion quality and standards; push back on shortcuts that create long-term cost — especially in code that touches funds or credit

### Communication & Collaboration
- Explain technical decisions clearly to both technical and non-technical stakeholders
- Represent engineering well in product and cross-functional discussions, including with Finance, Operations, and Credit on reconciliation, credit-risk, and dispute-handling questions
- Translate vendor documentation (Stripe, Lithic, and others) into clear, scoped engineering work
- Approach all assignments with a security lens — actively look for vulnerabilities in your own code and in the code you review, with extra care in PII and PCI-adjacent paths

## Requirements
- Strong foundation in computer science fundamentals: data structures, algorithms, and system design
- Expertise in building production-grade applications and services using Ruby and Ruby on Rails
- Extensive experience with PostgreSQL and SQL-based data modeling, including query optimization and performance tuning
- Deep understanding of web application security, observability, and scalable system architecture
- Proven ability to design, build, and maintain secure, scalable, and well-documented APIs
- Experience building integrations with external systems — REST/GraphQL APIs, webhooks, event-driven pipelines, or third-party vendor connections
- Hands-on experience with at least one payment processor or card issuer (Stripe, Lithic, Adyen, Marqeta, Braintree, or equivalents), or comparable fintech vendor work
- Working familiarity with at least one of: double-entry ledger design, idempotency / exactly-once patterns for webhooks and money-movement, ACH / wire / card-network basics, or reconciliation against vendor reports
- Familiarity with AWS and other cloud platforms, including infrastructure as code and CI/CD pipelines
- You are motivated by accountability — you own outcomes, not just tasks
- You are results-oriented and measure success by shipped, working software
- Writing tests is an integral part of your development process, not an afterthought
- You know how to design and build software incrementally
- You are collaborative, open-minded, and actively developing your craft
- Familiarity with AI-assisted development tools — you understand how they work, where they help, and where they fail

## Nice-to-Haves
- Prior hands-on use of AI-assisted development tools

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