A
TELEPHONY MODERNIZATION
Telephony platform migration
Planning the move from a legacy solution to a modern PBX platform, migrating tenants, routes, IVR, queues, recordings and integrations while maintaining service continuity.
9NE.PL // IT ENGINEERING
VoIP systems, Linux and applications
that work under pressure.
I design, deploy and repair systems that businesses depend on — from VoIP telephony and Linux infrastructure to security, automation and web applications.
- VoIP / SIP / PBX
- Architecture and diagnostics
- Linux / Security
- Stability and protection
- Web / Automation
- Systems built around your process
AREAS OF SPECIALISATION
VoIP / SIPDesign
LinuxMaintenance
ApplicationsDeployment
IncidentsDiagnostics
$
analyze --fix --document
SIPFreeSWITCHFusionPBXLinuxDockerWebRTCSecurityAutomation
01 // EXPERTISE
From the network layer
to the user interface.
I combine telecommunications, systems administration, security and programming. This lets me analyse the whole problem rather than pass it between teams.
Full range of services01
VoIP, SIP and PBX
Design and maintenance of telephony platforms, call routing, WebRTC, NAT, media, carrier integrations and advanced signalling diagnostics.
- FusionPBX / FreeSWITCH / OpenSIPS
- SIP traces, RTP and Wireshark
- HA, migrations and trunk integrations
02
Linux and infrastructure
Building, migrating and stabilising production environments. Configuration of services, networks, reverse proxies, containers, monitoring, backups and recovery procedures.
- Debian / Ubuntu / RHEL
- Docker, Nginx and systemd
- Migrations without unnecessary risk
03
IT security
Configuration reviews, attack surface reduction, system hardening, scan analysis and practical vulnerability remediation without destabilising production.
- Audits and risk analysis
- Firewall, TLS and access control
- Safe deployment of changes
04
Web applications
Custom panels, operational tools and websites. Frontend and backend built for straightforward maintenance, security and a real business process.
- Python, APIs and databases
- Modern frontend
- Deployment and maintenance
05
Automation and reporting
Scripts, integrations and reports that reduce manual work. I automate repetitive operations, aggregate data and build tools to simplify everyday system management.
- Python, Bash and scheduling
- API integrations and data processing
- Technical and business reports
06
Diagnostics and incident response
Intermittent problems across multiple layers that are difficult to reproduce. Analysis of logs, network traffic and application dependencies, followed by a lasting fix and documentation.
- RCA rather than quick workarounds
- tcpdump, Wireshark and log correlation
- Remediation and prevention
02 // SELECTED PROJECTS
Projects that run
in real environments.
From service websites and e-commerce to community platforms and business telephony. Explore selected projects I have designed and deployed.
All case studies
01 / 08Read the case study →
CYBERSECURITY / AI / EVIDENCE
AISeeRisk
A security audit platform combining an authorised scope, reliable evidence, risk prioritisation and controlled remediation with subsequent verification.
02 / 08Read the case study →
EVENTS / ORGANIZER PLATFORM
Eventnado
A two-sided event platform combining a catalogue and search for attendees with planning, administrative requirements, registration and event operations for organisers.
03 / 08Read the case study →
AI / VOIP / COMMUNICATION PLATFORM
Callchestra
A business communication orchestration platform combining AI agents, PBX, routing, workflows, call analytics and integrations in one controlled environment.
04 / 08Read the case study →
MONITORING / OBSERVABILITY
UPnator
A monitoring and reliability platform for websites, APIs, servers, databases and telephony, with alerts, status pages, incident history and SLO reports.
05 / 08Read the case study →
HEALTHCARE / BOOKING
Psycholog Spektrum
A psychology practice website combining a calm presentation of its services, appointment booking, contact forms and tools for everyday administration.
06 / 08Read the case study →
E-COMMERCE / HANDMADE
Sodashi Arts
An online shop for handmade crafts, scrapbooking and mixed media, designed around detailed product presentation, straightforward purchasing and everyday catalogue management.
07 / 08Read the case study →
VOIP / COMMUNICATION PLATFORM
RelayPBX
A platform for building and operating business telephony, combining visual configuration, routing, tenants, SIP diagnostics and different deployment models.
08 / 08Read the case study →
COMMUNITY / AUTOMOTIVE
Pokaż Brykę
A community for car projects with vehicle profiles, modification histories, rankings, categories, a Spotted module and engagement features.
TECHNICAL AREAS
Beyond web projects
I also deliver infrastructure, telecommunications and automation projects where reliability and diagnostics matter more than visual presentation.
B
REAL-TIME COMMUNICATION
WebRTC and media stabilisation
Diagnosing one-way audio, ICE, TURN, NAT, WSS and codec negotiation issues — from the browser through the SBC and PBX to the carrier.
C
PRODUCTION INFRASTRUCTURE
Safe server migration
Service inventory, new environment preparation, containerisation, reverse proxy, TLS, functional tests, DNS cutover and a plan to retire the old infrastructure.
D
OPERATIONS AUTOMATION
Process and reporting automation
Building scripts that gather data from multiple sources, generate recurring reports and eliminate repetitive administrative tasks.
03 // TECHNOLOGIES
Tools matter.
The outcome matters more.
I choose technology to suit the problem, constraints and how the system will be maintained. I do not add dependencies simply because they are fashionable.
Telecommunications
SIPRTPFreeSWITCHFusionPBXOpenSIPSAsteriskWebRTCTURN / STUN
Infrastructure
LinuxDockerNginxsystemdPostgreSQLMongoDBDNSTLS
Development
PythonFastAPIJavaScriptHTML / CSSREST APISQLBashGit
Analysis and security
WiresharktcpdumpNessusFirewallHardeningMonitoringLog analysisRCA
04 // HOW I WORK
Facts first.
Then the right change.
- 01
Diagnosis
I gather requirements, logs, network traces and dependencies. I separate symptoms from their cause.
- 02
Design
I prepare the solution, deployment approach, risks, test plan and a way back.
- 03
Deployment
I introduce the change in a controlled way, observe the system and verify the key scenarios.
- 04
Documentation
I document the configuration, outcome, technical decisions and recommendations so the solution remains understandable.
nameJarosław Staroń
roleIT specialist / engineer
focusreliable systems
methodanalyze → build → verify
05 // ABOUT ME
An engineering perspective
across system layers.
My name is Jarosław Staroń. I specialise in VoIP systems and Linux infrastructure, and regularly work across networking, security, backend, frontend and operations.
I focus on thorough analysis, communication without unnecessary jargon and maintainable solutions. When a system fails, I look for the root cause. When building from scratch, I design for production.
Tell me about your challenge →06 // KNOWLEDGE BASE
Practical articles for people who maintain systems.
I explain diagnostic methods, architectural decisions and deployment processes you can apply in real environments — from SIP traces to application rollback.
01VoIP and SIP
Advanced / 5 MIN
One-way audio in VoIP — NAT, RTP, SDP and firewalls
One-way audio is not a single problem. It is a class of failures involving signalling, address translation, media routing, ACLs and device behaviour.
Read02VoIP and SIP
Intermediate / 6 MIN
How to read a SIP trace and identify why a call fails
A practical method for analysing SIP signalling: from Call-ID and transactions, through routing and headers, to SDP, media and a precise RCA.
Read03Linux and infrastructure
Intermediate / 5 MIN
A safe production server migration, step by step
Migration does not start with copying files. It starts with an inventory, dependencies, acceptance criteria and a practical way back.
Read07 // CONTACT
Have a technical problem
or plans for a new system?
Briefly describe your environment, goal and main constraints. I will let you know whether and how I can help.