Technical Support Engineer - API & AI-Driven Troubleshooter

OneRail; Kraków; Hybrid; PLN 134,000 - 179,000; Full time

Job summary

OneRail in Kraków is seeking a Technical Support Engineer to serve as a frontline technical partner for customers. You’ll handle incoming technical issues, perform triage and deep investigation, debug problems across APIs, databases, integrations, and application behavior, and work closely with Engineering when escalation is required.

This is a hands-on role for someone who has already worked in technical or product support and enjoys digging into how systems work, not just passing tickets

Qualifications

• 2-4 years of experience in technical support, product support, software development, or a customer-facing technical role.
• Strong troubleshooting skills and comfort working through ambiguous problems independently.
• Comfort using modern AI‑assisted tools (e.g., for code understanding, debugging, or documentation) to improve investigation speed and accuracy.
• Ability to read and understand code (JavaScript / TypeScript preferred; other languages welcome).
• Hands-on experience debugging REST APIs (requests, responses, auth, payloads, status codes).
• Working knowledge of SQL for investigation and validation.
• Experience owning support tickets from intake through resolution.
• Clear written and verbal communication, including explaining technical issues to non-technical audiences.
• Comfortable collaborating with Engineering and Product teams during escalations.
• Advanced proficiency in English & Polish, both written and spoken (B2+).

Responsibilities

• Serve as a primary technical support contact for customer-reported issues.
• Triage incoming issues to assess severity, impact, and scope.
• Investigate problems using logs, monitoring tools, API requests, and SQL queries.
• Reproduce issues when possible and clearly document steps, conditions, and outcomes.
• Use AI‑assisted development tools to quickly understand unfamiliar code paths, APIs, and system behavior during investigations, to quickly understand expected behavior.
• Leverage AI tools to help analyze logs, error traces, and reproduction steps to accelerate root cause identification.
• Contribute to bug fixes, config updates, and other safe improvements, using AI tooling to assist with coding, validating, and reviewing changes before submitting for review.
• Escalate issues to Engineering with high-quality context: repro steps, evidence, suspected cause, and suggested next actions.
• Communicate technical findings clearly to internal stakeholders and, when appropriate, directly to customers.
• Maintain and improve support documentation, KB articles, runbooks, and SOPs.
• Identify recurring issues and trends; suggest improvements to tooling, logging, alerts, or documentation.

Skills

Troubleshooting

AI-assisted tools

Code reading (JS/TS)

REST API debugging

SQL queries

Ticket ownership

Clear communication

English & Polish (B2+)

Job description

OneRail in Kraków is seeking a Technical Support Engineer to serve as a frontline technical partner for customers. You’ll handle incoming technical issues, perform triage and deep investigation, debug problems across APIs, databases, integrations, and application behavior, and work closely with Engineering when escalation is required.

This is a hands-on role for someone who has already worked in technical or product support and enjoys digging into how systems work, not just passing tickets