Cloud & Telco Engineer (SIP / Reliability)

Intro
_For this position we are only looking for candidates located in Greece._
Nairon GmbH is a Swiss startup building AI voice agents that answer and make phone calls for businesses. Our platform runs real-time conversations over the phone and on the web, connected to our customers' telephony and business tools. We value clear communication, thoughtful engineering, and a collaborative approach to problem-solving. Join us as we continue to develop tools that make a difference.
You will own the hardest reliability problems on our platform: the telco edge where phone calls enter and leave, and the cloud infrastructure underneath that has to stay up during live calls.
Tasks
As a Cloud & Telco Engineer at Nairon GmbH, your responsibilities will include:
* Running and hardening our SIP edge: _Kamailio_\-based session border controllers, carrier and customer SIP trunks, PBX integrations, TLS and SRTP.
* Making calls survive failures: redundancy, failover between zones and providers, graceful draining and releases without dropped calls.
* Troubleshooting call quality at SIP and RTP level: NAT traversal, codecs, DTMF, one-way audio, transfers and re-INVITEs.
* Running _Kubernetes_ on _AWS_ and European clouds with GitOps (_Argo CD_, _Helm_) and _Terraform_.
* Observability and incident response: metrics, logs and traces (_OpenTelemetry_, _Grafana_), alerting, runbooks and postmortems.
* Load testing, capacity planning and cost at the edge.
Requirements
Experience:
Several years running production infrastructure where downtime is visible to customers, ideally in telecom, VoIP or real-time media.
Technical Skills:
Required:
* SIP in production: trunks, registrations, REFER and re-INVITE, NAT traversal, RTP, codecs and DTMF.
* Routing logic in a SIP proxy such as _Kamailio_ or _OpenSIPS_; GUI-only PBX administration is not enough.
* Linux networking and packet-level troubleshooting (_sngrep_, _Wireshark_, _SIPp_).
* _Kubernetes_ in production and infrastructure as code (_Terraform_ or similar).
Nice to have:
* _AWS_ networking (VPC, load balancers, IAM) and multi-region or multi-provider setups.
* _RTPengine_, _FreeSWITCH_ or _Asterisk_; _LiveKit_ or WebRTC.
* Carrier interconnects and number porting, in Greece or in the German-speaking markets we serve.
* _Python_ or Go for tooling and automation.
Communication:
* _English proficiency is essential, both written and spoken, as it is the working language for all positions._
Soft Skills:
* Calm during incidents; you find the root cause and write it down.
* You prefer boring, reliable systems over clever ones.
* Ownership: a call path that breaks is your problem until it is fixed.
Benefits
* Flexible Work Setup: Work fully remotely or from a co-working space — whichever suits you best.
* Equipment Provided: Company laptop and phone provided for all employees.
* Collaborative Environment: Join a small, agile team where your contributions have a direct impact.
* Growth Opportunities: Own the path of every call, from the carrier to the AI agent.
Closing
If you enjoy making phone calls and infrastructure work reliably under real load, we'd love to hear from you.