Lead Java Developer

Job Title: Sr Java Card / eSIM Applet Developer

Location:
India Pune

Reports To:
Engineering Team Lead

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 2G–5G and LTE-M coverage from over 800 radio network operators—300 of which are direct partners—across 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 connectivity—enabling a wide array of innovative cloud-based solutions.

Position Overview

The
Senior eSIM Applet Developer
will own the
entire lifecycle
of eSIM Java applet development — from requirements definition and architecture through coding, testing, certification, and deployment. This role requires deep technical expertise in
Java Card
,
SIM/eSIM environments
, and
secure element application development
.

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