SIM Engineer
telnyx54 • Ho Chi Minh City, Vietnam; Bangalore, India
Posted: May 14, 2026
Job Description
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+ year 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)
#LI-RH1
Additional Content
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+ year 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)
#LI-RH1