SIM Engineer
About this role
About Telnyx
Telnyx is an industry leader that's not just imagining the future of global connectivity—we're building it. From architecting and amplifying the reach of a private, global, multi-cloud IP network, to bringing hyperlocal edge technology right to your fingertips through intuitive APIs, we're shaping a new era of seamless interconnection between people, devices, and applications.
We're driven by a desire to transform and modernize what's antiquated, automate the manual, and solve real-world problems through innovative connectivity solutions. As a testament to our success, we're proud to stand as a financially stable and profitable company. Our robust profitability allows us not only to invest in pioneering technologies but also to foster an environment of continuous learning and growth for our team.
Our collective vision is a world where borderless connectivity fuels limitless innovation. By joining us, you can be part of laying the foundations for this interconnected future. We're currently seeking passionate individuals who are excited about the opportunity to contribute to an industry-shaping company while growing their own skills and careers.
About you
We're looking for a Junior SIM Engineer with a technical background and a drive to specialize in SIM and eUICC engineering. You're organized, detail-oriented, and genuinely curious about how SIMs work — from profile structures and file systems to eSIM provisioning and OTA updates. You're comfortable with scripting and automation, and you see AI as a productivity multiplier — whether that's automating repetitive tasks, generating documentation, or building internal tooling.
The opportunity
You'll join the Mobile Core Services squad, responsible for subscriber identity & authentication, core network services, and subscriber data & policy across the Telnyx wireless network. You'll work on the technical foundations of our SIM and eSIM product — learning from a senior SIM engineer while contributing to day-to-day operations, profile management, and new feature delivery.
Telnyx operates as a global MVNO/MVNE, provisioning millions of SIMs across multiple profile vendors and eSIM platforms. You'll learn the SIM lifecycle end-to-end while building real expertise in a niche, high-value domain.
Responsibilities
• Support SIM/eSIM profile creation and management across multiple vendor platforms
• Assist with eSIM DP+ operations: profile download, activation, and lifecycle management
• Perform and validate OTA updates for SIM applets and file structures
• Manage SIM logistics: ordering, fulfillment, stock tracking, and shipment coordination
• Support BAP (Baseline Application Profile) creation and maintenance
• Troubleshoot SIM-related issues reported by customers or internal teams
• Maintain documentation for SIM processes, configurations, and vendor procedures
• Coordinate with Mobile Platform Engineering on HSS/subscription provisioning
• Assist with testing and validation of new SIM features before production rollout
What we're looking for
• 1-3+ years in telecom, IT, or a related technical field (internship experience counts)
• Understanding of SIM/UICC fundamentals: file systems (EF/DF structures), applets, USIM/ISIM
• Basic familiarity with at least one SIM profile creation tool or vendor platform
• Willingness to learn eSIM and Remote SIM Provisioning standards (GSMA SGP.22, SGP.32)
• Organized and detail-oriented — SIM logistics and profile management require accuracy
• Comfortable with scripting or automation (Python, Bash, or similar)
• Strong written communication for documentation and cross-team coordination
• Interest in using AI tools to enhance productivity — automating tasks, generating docs, analyzing logs, or building tooling
Bonus points
• Experience with eSIM DP+ platforms or RSP systems (SMDP+/SMDS)
• Familiarity with Java Card or SIM applet development
• Understanding of OTA update mechanisms (SCP02, SCP03, SCP80, SCP81)
• Knowledge of GlobalPlatform for secure element lifecycle management
• Understanding of LTE/5G network attach and SIM authentication (AKA, EPS-AKA)
• Experience with SIM management systems (OTAAP, SMSC)
• Experience building AI-assisted workflows (LLM-powered tooling, copilots, automated reporting)
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