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 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
