Experienced Senior Software Engineer

1oT is looking for an Experienced Senior Software Engineer to help us build connectivity solutions based on the latest eSIM IoT standard.


1oT has built a platform that helps global IoT service providers manage their SIM cards and billing. Our self-service platform lets users control and monitor SIM card sessions, switch SIMs on and off, purchase new SIMs, send SMS messages, and more. We work with clients across e-mobility, asset tracking, and smart city solutions, so you'll get exposure to a wide range of IoT sectors and telecom companies.


1oT eSIM team builds and maintains services that implement the M2M, Consumer and IoT eSIM specifications of GSMA.

Number of vacancies

1

Deadline for applying

31.01.2026

Job location

Tallinn

Work assignments

  • Develop large-scale services using Java, REST, Spring, and SQL
  • Contribute to our back-office UI built with Vue.js
  • Run and maintain our services in AWS using Terraform, Docker, and Grafana
  • Lead discussions on the platform's architecture
  • Identify bottlenecks in the team's technical solutions
  • Lead the implementation of technical initiatives
  • Prioritize security and compliance in development initiatives
  • Mentor junior team members on best practices and ways of working
  • Ensure that eSIM services are built according to GSMA specifications
  • Handle external integrations via APIs

Work experience

  • 6+ years of development experience with Java, REST, Spring, and SQL
  • Previous experience as a Senior Engineer, Solution Architect, or Tech Lead
  • Experience with cloud-hosted services (AWS, Azure, or GCP)
  • Familiarity with modern UI frameworks is a huge plus
  • Experience with cryptography or HSM is a huge plus

Personal qualities

  • Enjoy working as part of a team and like driving technical discussions forward
  • Approach challenges with a problem-solver mindset and focus on getting things done
  • Take strong ownership of your work
  • Have the curiosity and drive to build products that don't yet exist

Language skills

English

Additional requirements

  • Ability to work with APIs and integrations
  • Comfortable with security-focused development
  • Willingness to mentor and guide other engineers
  • Readiness to take ownership of technical domains

Company/organization offers

  • Meaningful, globally impactful work on cutting-edge eSIM technology
  • Diverse tasks—from building new features to optimizing existing systems
  • Influence and ownership within a growing, sustainable company
  • A cozy and productive work environment at our Tallinn HQ
  • Ambitious teammates who challenge the status quo
  • A supportive, fun team with great vibes
Technical EngineeringInformation Technology
  • Work time: Full time work
  • Workload: 1
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