Senior JS/Go Developer - English must have

Role Summary
We are hiring a Senior Golang Engineer to join the Integrations team. This vertical owns the third-party and partner integrations, external API contracts, integration middleware, and cross-system data contracts that connect the platform to outside vendors and services.
The Senior
Engineer is accountable for designing, building, and running high-quality Golang integration services. They also drive day-to-day execution mechanics within the team, uphold engineering standards, and act as a technical reference point for less experienced engineers.
This is a primarily hands-on role with an approximate 85% hands-on / 15% technical leadership split. The Team Lead governs team outcomes; the Senior Engineer owns the technical quality of the work they and their pairs deliver.
Key Responsibilities
Design, implement, and maintain Golang integration services (partner/vendor APIs, integration middleware, cross-system contracts).
Decompose complex features into well-scoped, estimable tasks together with the Team Lead and contribute to realistic sprint commitments.
Deliver committed sprint scope with high code quality, solid test coverage, and clear documentation.
Perform thorough code reviews and act as named senior reviewer, including for AI-assisted changes.
Apply architecture and engineering standards within team scope and raise deviations early.
Own runtime health of the services you build - observability, alerting, performance - and take part in incident diagnosis, resolution, and the on-call rotation.
Implement API versioning and backward-compatibility practices so integration changes ship with migration paths and no undocumented breaking changes.
Surface technical risks, blockers, and dependencies early to the Team Lead.
Mentor junior and mid-level engineers through pairing, reviews, and knowledge sharing.
Required Experience
5+ years of professional software engineering experience, including 3+ years of recent production experience with Golang.
Proven track record of designing, shipping, and operating backend services in production.
Experience building and consuming external / third-party APIs and integrations.
Experience operating in a microservice, multi-repo environment.
Experience mentoring or reviewing the work of other engineers.
Hands-on experience using AI coding tools in a production team setting, with awareness of review/QA guard rails.
Required Technical Skills
3+ years of experience with Golang (concurrency, goroutines/channels, context, error handling, testing, profiling).
5+ years of experience with one of the following languages: Golang, C++, C#, Java, or [protected info] / TypeScript / JavaScript.
Experience with designing and/or implementing distributed systems.
Experience with designing and/or implementing microservice-oriented architecture.
Experience with design and implementation of RESTful web services.
Experience with Git.
Experience with NoSQL.
Knowledge of UML or similar design languages/methodologies.
Strong knowledge of TCP/IP and HTTP protocol stacks.
Strong analytical and problem-solving skills.
Experience working in Linux environments.
Ability to work in a team-oriented environment, and can work independently.
Experience working in an Agile Development environment.
Strong written and verbal communication in English.
Advanced knowledge of OOP/OOD, design patterns, and SOLID.
Valued / Secondary Skills
[protected info] with JavaScript and TypeScript.
Experience with performance tuning of large-scale platforms.
Experience using tools such as GitLab, SVN, Jira, Confluence, Docker.
Experience with Cassandra, ElasticSearch, and/or Postgres.
Experience with any of the following is considered a strong plus: RabbitMQ, Kafka, Protocol Buffers, gRPC, Redis, JWT, OAuth2.
Experience with observability tooling (metrics, tracing, structured logging) and production troubleshooting.
Experience integrating third-party / external vendor systems.
Prior work in regulated or high-availability environments (online gaming/casino domain a plus).
Leadership & Soft Skills
Takes ownership of delivery and quality for their own work and the features they lead.
Strong written and spoken English - all organizational communication is in English; the team includes distributed engineers.
Willingness to mentor and support junior and mid-level engineers.
Comfortable distinguishing what can be solved within the team versus what needs escalation to the Team Lead.
Effective communication with QA, other verticals, and external partners on shared contracts and dependencies.
Role Boundaries (Cannot Do)
This role explicitly does not:
Approve production releases (release approval is Technical Director authority).
Override architecture standards (Chief Architect owns enterprise standards).
Commit sprint scope or delivery dates on behalf of the team (Team Lead authority).
Redefine cross-team or external API contracts unilaterally.
Hold hiring, budget, or prioritization authority.
Success Metrics (First 6-12 Months)
Consistent delivery of committed sprint scope with high quality.
Zero undocumented breaking API changes in owned services; backward-compatibility discipline upheld.
Owned integration services stable within SLA, with effective incident participation.
Code review turnaround and engineering-standard compliance at team expectations.
Visible growth of mentored engineers.
AI-assisted development used effectively within approved tooling and guard rails - defect rate at or below baseline, no increase in review overhead.