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 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
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 cryptography 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
