SIM Over-The-Air (OTA) Developer

Flint UK Technology Services; Greater London; Hybrid; GBP 60,000 - 80,000; Full time

Job summary

A technology services provider is looking for experienced SIM Over-The-Air (OTA) Developers to support the design and maintenance of OTA solutions for SIM/eSIM platforms. The role involves developing applications compliant with 3GPP and GSMA standards, implementing secure messaging, and collaborating with cross-functional teams to ensure end-to-end solutions. This position offers the flexibility of remote, hybrid, or onsite work in England, and seeks candidates with strong skills in OTA technologies and programming, especially in Java and C/C++.

Qualifications

• Strong experience in SIM OTA technologies.
• Hands-on experience with SIM Toolkit (STK) and OTA protocols.
• Knowledge of cryptography and secure messaging.

Responsibilities

• Design and maintain SIM OTA applications compliant with 3GPP and GSMA standards.
• Implement secure OTA messaging for SIM provisioning and updates.
• Collaborate with teams to deliver end-to-end OTA solutions.

Skills

SIM OTA technologies

Programming in Java

Programming in C/C++

Programming in Python

Cryptography and key management

SMPP and SMSC integration

Mobile telecom ecosystems

OTA protocols (SMS-PP, CAT-TP, SCP80/SCP81)

eSIM/RSP architecture

Tools

SIM Toolkit (STK)/Java Card

Job description

SIM Over-The-Air (OTA) Developer

Contract Type

12-Month Contract (Extendable based on project needs)

Location

Remote/Hybrid/Onsite (as applicable)

Start Date

TBD

Role Overview

We are seeking experienced SIM Over-The-Air (OTA) Developers to support the design, development, deployment, and maintenance of OTA solutions for SIM/eSIM platforms. The role focuses on secure remote provisioning, life cycle management, and updates of SIM profiles across large-scale mobile networks.

Key Responsibilities

• Design, develop, and maintain SIM OTA applications in compliance with 3GPP and GSMA standards
• Implement secure OTA messaging for SIM/eSIM provisioning, updates, and life cycle management
• Integrate OTA platforms with HSMs, SMSCs, SMPP gateways, and mobile core systems
• Develop and manage SIM Toolkit (STK)/CAT-TP based applications
• Support eSIM (Remote SIM Provisioning - RSP) workflows including profile download, enablement, and deletion
• Perform OTA testing, validation, and troubleshooting across multiple devices and operators
• Ensure compliance with security, encryption, and key management standards
• Collaborate with network, security, and platform teams to deliver end-to‑end OTA solutions
• Provide documentation, deployment support, and knowledge transfer

Required Skills & Experience

Technical Skills

• Strong experience in SIM OTA technologies
• Hands‑on experience with:
  • SIM Toolkit (STK)/Java Card
  • OTA protocols (SMS-PP, CAT-TP, SCP80/SCP81)
  • 3GPP, ETSI, and GSMA specifications
• Experience with eSIM/RSP architecture
• Knowledge of cryptography, key management, and secure messaging
• Familiarity with SMPP, SMSC integration, and mobile network environments
• Programming experience in Java, C/C++, or Python

Domain Knowledge

• Mobile telecom ecosystems and SIM life cycle management
• SIM personalization, provisioning, and OTA security domains

Preferred/Nice-to-Have

• Experience with OTA platforms (eg, Thales, G+D, IDEMIA, or equivalent)
• Exposure to IoT SIM/eSIM deployments
• Experience working with HSMs and secure key injection
• Familiarity with CI/CD pipelines in telecom environments
• Prior experience in large‑scale operator or MVNO environments