Lead Java Developer

Job Title: Sr Java Card / eSIM Applet Developer

Location:

Reports To:

About Telna

Telna provides Mobile Network Operators (MNOs), Communication Service Providers (CSPs), and Original Equipment Manufacturers (OEMs) with a fully managed global cellular connectivity platform. With access to the largest 2G5G and LTE-M coverage from over 800 radio network operators300 of which are direct partnersacross 200 countries, Telna empowers seamless, high-performance connectivity worldwide.

Our global multi-network connectivity platform simplifies integration, offering localized break-out capabilities via cloud infrastructure. With a single integration into Telna's platform, millions of devices are powered by resilient, multi-network connectivityenabling a wide array of innovative cloud-based solutions.

Position Overview

Senior eSIM Applet Developer

You will collaborate with product, platform, and QA teams to design, develop, and maintain Telna's next-generation eSIM applets, ensuring compliance with GSMA, ETSI, and GlobalPlatform standards.

Key Responsibilities

• Own full applet lifecycle:

  from requirements gathering, design, and development to testing, certification, and release.

• Develop and maintain Java Card applets

  for SIM, USIM, and eSIM (eUICC) environments.

• Implement, debug, and troubleshoot applet

  logic on various SIM/eSIM platforms and toolchains.

• Collaborate with OEMs, chipset vendors, and MNOs

  to integrate and validate applet functionality.

• Ensure compliance

  with GSMA, ETSI, and GlobalPlatform standards for SIM/eSIM applets.

• Conduct code reviews, test case design, and performance analysis.

• Work closely with QA to automate testing and validation in both simulated and real device environments.
• Prepare and maintain technical documentation (design specs, test plans, release notes).
• Stay current with advancements in

  eSIM technology, secure element design

  , and

  Java Card platform updates.

Required Qualifications

• Bachelor's or Master's degree in Computer Science, Electrical Engineering, or related field.

• 5+ years

  of hands-on experience developing

  Java Card applets

  for SIM, USIM, or eSIM.
• Deep understanding of:

• Java Card 3.x / GlobalPlatform 2.x

  standards

• APDU communication and ISO 7816

• Security domains, SCP02/SCP03, and OTA mechanisms

• Experience with

  SIM/eSIM development and debugging tools

  (Gemalto, G&D, Thales, VALID, etc.).
• Strong knowledge of

  GSMA SGP.02 / SGP.22 / SGP.32

  specifications.
• Experience deploying and testing applets on

  UICC/eUICC

  hardware.
• Proficiency in troubleshooting using logs, traces, and APDU-level analysis.
• Solid understanding of c

  ryptography and key management

  in secure element contexts.
• Excellent problem-solving skills and attention to detail.
• Strong communication and documentation skills.

Preferred Qualifications

• Experience with

  remote SIM provisioning (RSP)

  environments.
• Knowledge of

  OTA platforms

  and

  backend integration

  with SIM lifecycle management systems.
• Familiarity with

  embedded systems

  or

  secure hardware modules

  .
• Previous work in telecom or IoT connectivity environments

  .

Why Join Us

• Contribute to the advancement of cutting-edge telecom technologies and infrastructure
• Collaborate with a diverse, experienced, and multicultural team of engineers and industry professionals
• Enjoy a flexible work environment with remote work options
• Receive a competitive salary and comprehensive benefits package
• Grow your career through professional development opportunities and technical training