Technical Support Engineer — Alternative Payment Methods (APM)
Unlimit is a London-based global fintech providing cross-border payment processing, business accounts, banking-as-a-service, card issuing, and crypto/stablecoin payment infrastructure.
About Unlimit
Founded in 2009, Unlimit operates a global financial-services platform for businesses, combining payment processing, local and international payment methods, multicurrency business accounts, banking-as-a-service APIs, card issuing, payment rails, and digital-asset on/off-ramp capabilities. The company is headquartered in London and operates across multiple continents.
Skills
Candidate Availability
Required and preferred rules are kept separate and reflect the wording in the original posting.
About the Role
This role serves as the top-tier technical expert for merchants, Product and Engineering teams, and external payment partners. It focuses on complex incident resolution, root-cause analysis, monitoring, operational improvements, APM integration support, and high-volume payment reliability.
Requirements
- Deep understanding of payment processing workflows, APM models, and related regional regulations.
- Experience with REST APIs, webhooks, JSON, and authentication protocols.
- Proficiency with Datadog, Grafana, Kibana, ELK Stack, or Splunk.
- Strong SQL proficiency for transactional data analysis.
- Ability to read and debug Python, Node.js, or Java code.
- Familiarity with microservices, AWS or GCP, and CI/CD pipelines is a plus.
- AI-driven mindset and curiosity about emerging AI technologies.
- Hands-on experience using AI tools to improve productivity or system performance.
- 4–7+ years of experience in senior technical support, payments engineering, or integration engineering.
- Experience in a high-volume PSP, fintech, or banking environment is strongly preferred.
- Experience supporting global payment methods and high-traffic systems.
- Strong problem-solving, analytical, communication, incident-management, and ownership skills.
Responsibilities
- Serve as the highest escalation point for critical APM-related issues.
- Troubleshoot complex transaction failures, including authorization declines, settlement discrepancies, callback issues, and routing problems.
- Analyze system anomalies using logging and monitoring tools.
- Coordinate incident resolution with Engineering and DevOps.
- Lead emergency response during major outages.
- Conduct post-incident root-cause analysis and present findings.
- Develop and maintain APM monitoring dashboards, alerts, and health checks.
- Analyze payment success rates, latency, and drop-off rates.
- Provide technical consultation to merchants integrating APMs.
- Review API specifications, payloads, webhooks, and authentication mechanisms.
- Support integration testing and APM certification.
- Drive automation and tooling improvements to reduce recurring incidents.
- Create runbooks, troubleshooting guides, and operational documentation.
- Serve as the APM subject matter expert across internal teams.
- Act as the primary technical contact for APM providers and acquirers.
- Manage escalations and partner SLAs.
- Validate the impact of provider updates and API changes.
