Mobile Core Engineer, Carrier

TextNow, Inc.
United States
Hybrid

Who this role is best for

Best suited to experienced carrier mobile core operators with cloud-native and AI integration skills working in a hybrid, geographically distributed team. The role emphasizes technical depth in 4G/5G core functions and collaboration with SRE and developers.

Best fit for

  • Experienced carrier mobile core operators with cloud-native and AI integration skills
    — “You've run a mobile core at a carrier and want to do it on a cloud-native platform.”
  • Candidates who lead production incidents and define monitoring strategies
    — “You'll lead core incidents: protocol, charging and policy issues.”
  • Individuals who can translate network knowledge into automation and runbooks
    — “Teach the automation what good looks like. Turn your network knowledge into runbooks, health checks and investigation steps that AI agents can follow.”

Things to consider

  • Travel to Canada is required several times a year for lab work and team meetings
    — “You'll travel to our Waterloo office a few times a year to work in the device lab and meet the team”
  • The role requires managing both subscriber and network capacity planning
    — “Own capacity and SIMs: subscriber, session and license headroom”

How to stand out

  • Emphasize your experience in defining monitoring alarms and KPIs for mobile core systems
    — “Define what we monitor: the alarms, KPIs and thresholds that matter”
  • Showcase your ability to lead core incidents and identify root causes
    — “Lead core incidents: protocol, charging and policy issues. Read the capture, find the cause.”
  • Highlight your hands-on experience with EPC/5GC packet core functions like PGW, SMF, and UPF
    — “Hands-on EPC/5GC packet core (PGW, SMF, UPF); working knowledge of IMS”
  • Demonstrate your ability to use AI for triaging alarms and analyzing logs
    — “Use AI across the job: triaging alarms, reading logs and captures”
  • Show a track record of writing and executing MOPs, upgrades, and maintenance windows
    — “You've written and run MOPs, upgrades and maintenance windows in production”
Pace · Fast PacedCollaboration · HighAutonomy · HighDecision Impact · Team

Derived from job-description analysis by Serendipath's career intelligence engine.

What success looks like

  • Successfully operated a converged 4G/5G mobile core in AWS
Typical background
5+ years operating a live mobile core in production for an operator

Skills & requirements

Required

Mobile Core OperationsCloud-native PlatformsNetwork FunctionsPacket CoreIMSPolicy And ChargingPacket Capture AnalysisVendor Software ValidationCapacity ManagementSIM ManagementPartner And Device OnboardingCore IncidentsVoice InterconnectRoaming SignalingLawful InterceptAI Integration

Preferred

SREDevelopersAutomationNetwork Security

Stack & domain

Mobile CoreCloud-native Platform4g/5gAWSEpc/5gc Packet CoreIMSPolicy And ChargingLawful InterceptAILeadershipTeamworkProblem-solvingNetwork OperationsTelecommunications

About the role

Original posting from TextNow, Inc. via Greenhouse

TextNow is a full MVNO. We run our own converged 4G/5G mobile core in AWS for hundreds of thousands of subscribers, growing toward millions, and we're growing the team that owns and evolves it. AI is built into how this team works: it's how a small team operates, triages and changes a network this size.

About the role

You've run a mobile core at a carrier and want to do it on a cloud-native platform. You'll be the person on the team who knows what the network is supposed to do: how an attach should flow, why a Diameter or SIP request failed, what a policy rule does to a subscriber's traffic.

You'll work alongside our SRE, who owns the cloud platform, and developers who build the services around the core.

Where you'll work: remote anywhere in the US or Canada, with working hours that overlap Eastern time. You'll travel to our Waterloo office a few times a year to work in the device lab and meet the team, so you need to be able to travel to Canada.

What you'll do

Operate our converged 4G/5G core: packet core, IMS, HSS/UDM and related network functions.

Define what we monitor: the alarms, KPIs and thresholds that matter, wired into paging with SRE.

Own config changes: change plans, rollback criteria and impact analysis, shipped through the change pipeline our SRE runs.

Validate vendor software in our lab before it reaches production.

Own capacity and SIMs: subscriber, session and license headroom, SIM management and over-the-air (OTA) updates.

Lead partner and device onboarding: devices (UE), roaming partners and SIM profiles. You'll learn the parts that are new to you and lead the area.

Lead core incidents: protocol, charging and policy issues. Read the capture, find the cause.

Lead voice interconnect and roaming signalling: SBCs and SIP trunks, Diameter routing and IPX, and signalling security, so fraud and spoofed signalling get caught early. You'll learn the parts that are new to you.

Keep lawful intercept working with the team, with checks so changes don't break it.

Work with our vendor on defects, bringing evidence to every escalation and pushing for root causes that hold up.

Teach the automation what good looks like. Turn your network knowledge into runbooks, health checks and investigation steps that AI agents can follow. Lead on core alarm correlation, config change auditing and unusual call or data session patterns.

Bring the team up to speed. The SRE and developers all ramp up on the core and share on-call for it with you. You set the direction for the core, and the team shares the load.

Use AI across the job: triaging alarms, reading logs and captures, digging through vendor docs, drafting change plans.

Who you are

5+ years operating a live mobile core in production for an operator (carrier, MVNO or MVNE). Vendor experience counts if you were on call for a customer's live network

Hands-on EPC/5GC packet core (PGW, SMF, UPF); working knowledge of IMS

Working knowledge of policy and charging (PCRF/PCF, OCS, quota enforcement)

Comfortable reading and dissecting a packet capture end to end

You've written and run MOPs, upgrades and maintenance windows in production

You've led production incidents

Comfortable deciding what "correct" looks like when nobody else knows

You don't settle for how things have always been done. You look for better ways to run the network, even when "that's how carriers do it" is the easy answer

You already use AI to triage, analyze logs and captures, and automate the repetitive parts of operations

Nice to have

Alarm correlation or noise reduction on vendor network function alarms, or automated runbooks for core operations

Cloud-native network functions on Kubernetes

DPI-based traffic classification

Onboarding and troubleshooting devices (UE)

Working with GSMA roaming specs (IR.21, IR.88)

Python or Go, git, kubectl

Base Salary Range

The expected base salary range for this role is: $123,900 - $298,800 a year

United States (All other areas not listed above): USD $123,900 - $249,000  

United States (NYC, CT, NJ, Seattle, LA, San Diego): USD $136,300 - $273,900  

United States (San Francisco / Bay Area): USD $148,700 - $298,800  

 Our salary ranges are determined by role, level, and location. Within the range, individual pay is determined by job-related skills, experience, and relevant education or training. 

Our goal is to offer a competitive package that reflects the impact and expertise you bring to the team. 

This posting is for a current, active vacancy.

More about TextNow 

Our culture 

We’re proud of the culture that we’ve built at TextNow, but one of the most common questions we hear is ‘how do you continue to sustain it as the world and the company continues to change?’ The reality is that we’re only able to keep up because each and every TextNovian contributes to our culture through being involved, by living our values, sharing feedback, embracing change and more!  

 Our values 

Customer Obsessed 

We strive to have a deep understanding of our customers. 

Do Right By Our People 

We treat each other with fairness, respect, and integrity. 

Accept the Challenge 

We adopt a "Yes, We Can" mindset to achieve ambitious goals. 

Act Like an Owner 

We treat this company like it's our own... because it is! 

Give a Damn 

We are deeply committed and passionate about our work and achieving results. 

Our benefits and more 

This is a brief overview of the benefits that TextNow offers its employees. More complete details can be found in TextNow’s Benefit Guide and legal plan documents, which are available to employees on or shortly after their start date with TextNow. The benefits listed herein are for illustrative purposes only and may change from time-to-time in TextNow’s sole discretion. 

Free phone service 

Strong work life blend  

Employee stock options  

Unlimited vacation  

12 paid holidays per year 

Competitive pay 

Health, dental, and vision benefits 

Short-term & long-term disability 

$750 annual wellness benefit or healthcare spending account 

401(K) matching   

Parental leave for eligible employees 

Learning & Development opportunities

We travel a few times a year for various team events, company-wide off-sites, and more 

More information about our total rewards package will be available during the hiring process. 

Dogfooding & Customer Obsession 

At TextNow, every employee gets to actively use our app for calling and texting. Dogfooding helps us experience what customers do, to spot issues early, and drive better design, developer, and user experiences. 

Diversity and Inclusion 

Our aim is to make every person who joins TextNow feel like they belong, that they’re valued, and that they’re able to be their authentic selves at work.  

We’re all accountable for creating an inclusive culture and a sense of belonging for one another. By doing this together, we’ll make TextNow better for everyone.  

Equal opportunity 

We are an equal opportunity employer and are committed to creating an inclusive environment for all employees. We consider all qualified applicants without regard to race, color, religion, sex, gender identity or expression, sexual orientation, age, disability, or any other protected characteristic. 

Applicants who require reasonable accommodation during the hiring process may contact our Talent Team. 

AI usage: We use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact our Talent Team.

TextNow Candidate Policy 

By submitting an application to TextNow, you agree to the collection, use, and disclosure of your personal information in accordance with the TextNow Candidate Policy 

Source: TextNow, Inc. careers (Greenhouse)

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