CONFIDENTIAL PROJECT
Multi-Tenant IP PBX & UCaaS Platform
One administration plane and API for many organizations, extensions and devices — without mixing tenant call data.
View case study →
AI · Real-Time · Business Software
Vertical SaaS, AI, Voice & Business Platform Engineering
Ship domain software—education ERP, restaurant & hotel ops, membership loyalty, PM/workgroups, insurance & telecom ERP, marketplaces with telephony, device license desks, AI equity research—plus the voice and AI planes when the product needs them.
Stacks on public case studies include Laravel & CodeIgniter, NestJS & Next.js, Vue/React, React Native, Ionic & Android Studio, PostgreSQL/MySQL, Asterisk 22 & FreeSWITCH, and LLM/RAG with explicit integration boundaries—not a generic dev shop or hosted-PBX login.
School ERP · Hospitality & PMS · Loyalty · PM tool · Device AMC · Expert marketplace · SandeshX CPaaS · EAIBAP · PBX/CCaaS · AI voice
One practice · complete stack
UNIFIEDPBXProduct engineering planes
- business
- CRM / ERP · industry workflows · SaaS
- ai
- Agents · RAG · Automation · AI Voice
- realtime
- FreeSWITCH · Asterisk · WebRTC · SIP
- app
- Next.js · NestJS · Python · PostgreSQL
- ops
- Linux · Docker · AWS/Azure/GCP · Prometheus · OpenTelemetry
✓ AI + business software + real-time + production
At a glance
Experience
20+ years engineering
Delivery
90+ Upwork projects
Scope
E2E to production
Proof
15+ case studies · 45 demos
WHAT I BUILD
Product engineering across AI, business software and real-time systems
Telecom is the deepest specialization — not the only definition of the practice. Start with the capability your buyer is searching for.
START HERE
Problems solved — pick the job, not the framework
Buyers search for the outcome. Each row names a common pain, the business domain and where to read proof on this site.
Your team spends hours on repetitive business workflows
Problem: Manual lead qualification, document processing, customer follow-up and data entry burn hours every week.
Solution: AI agents + deterministic automation + CRM/ERP integration — with human escalation when confidence drops.
AI Agentsn8nCRM / ERP
AI Agent & Automation →
n8n workflows →
Your knowledge is scattered across documents and databases
Problem: Employees cannot quickly find reliable answers across docs, tickets, CRM fields and operational DBs.
Solution: RAG + enterprise search + knowledge graphs + controlled AI access tied to your systems of record.
RAGNeo4jPostgreSQL
AI & Data Engineering →
Private AI Architect →
Your AI prototype isn’t production-ready
Problem: Slow responses, uncontrolled costs, unreliable workflows and no observability after the demo works.
Solution: Production AI architecture — model routing, retries, monitoring, tool boundaries and human escalation.
Production AIObservabilityHITL
AI production architecture →
Agent engineering →
After the call, five tools own the work
Problem: Leads, GST-style bills, stock and HR live in different products — the desk re-types what the phone already captured.
Solution: One CRM/ERP login with telecom or insurance workflow baked in.
CRM / ERPTelecomInsurance
Custom CRM & ERP →
Clixxo case study →
CRM, dialer, campaigns and AI pilots do not share one tenant record
Problem: RevOps, BPO and vertical SaaS teams stitch HubSpot, dialers and AI experiments together—tenant boundaries, consent and call-session state stay inconsistent.
Solution: Commission a multi-tenant CRM + workflow + integration hub (optional voice)—industry packs for insurance, collections, BPO or owned vertical SaaS.
RevOps SaaSWorkflowsAI agentsVoice
EAIBAP product & estimator →
Industry workflow hub →
Technical case study →
You resell seats, not own the platform
Problem: Zoom or a locked UCaaS bill grows forever; tenants, billing and white-label are not yours.
Solution: Multi-tenant hosted PBX or CCaaS with isolation, RBAC and provisioning you control.
Multi-tenant PBXCCaaSBilling
Multi-tenant PBX →
CCaaS case study →
Field crews and customers need one API
Problem: Dispatch, payouts and mobile apps drift from the admin desk — duplicate rules in spreadsheets and app stores.
Solution: Laravel or NestJS backend plus React Native, Ionic or native Android on the same JSON API.
Field serviceLaravelReact NativeIonic
Field service platform →
Care home platform →
Becketts Android →
Missed inbound or agents without context
Problem: IVR dead-ends, no click-to-dial, or AI demos that cannot transfer to a human queue.
Solution: WebRTC desk, programmable IVR and hybrid AI + human queues on real SIP.
WebRTCAI VoiceIVR
AI call center →
WebRTC softphone →
Twilio IVR testing platform →
It works in development — production is paging
Problem: One-way audio, dead trunks, WebRTC ICE failures, flaky AI tools or API timeouts — the incident is already paging.
Solution: Trace across application, API, database, network, SIP/RTP, AI and infrastructure — then Debug → Stabilize → Monitor → Modernize.
RescueSIP / RTPAI / APIsObservability
Production rescue →
SIP/WebRTC diagnostic lab →
FusionPBX toll-fraud monitor →
Rescue articles →
Vertical product, not a chatbot wrapper
Problem: Legal, markets, messaging or hospitality rules must live in the app — not in a generic LLM prompt.
Solution: Domain products with APIs first: Indian-law assistant, SandeshX CPaaS, portfolio P&L, event and school ERP.
Domain SaaSLegal AIMessaging
Domain products →
All capabilities →
AI ENGINEERING
AI that works inside the business — not beside it
Build AI systems that connect your business data, CRM, ERP, communications and workflows — with tools, retrieval and human escalation designed in.
AI Agents
RAG
Knowledge Graphs
AI Voice
Lead Intelligence
Workflow Automation
Multi-Agent Systems
LLM Integration
AI Observability
Agentic AI & Intelligent Automation
Design AI agents that use tools, retrieve enterprise knowledge, interact with APIs, coordinate workflows and escalate to humans when required.
Agent loop
Business eventLead · ticket · document
AI agentRAG · CRM · ERP · APIs · KG
DecisionScore · route · draft
Automationn8n · webhooks
Human approvalWhen needed
Business actionCRM update · call · message
Why this combination matters
AI + Business Systems + Real-Time Communications — most providers specialize in one layer. You can connect all three.
Connected product
CRM / ERPSystem of record
AI agentRAG · tools
Automationn8n · APIs
CommunicationAsterisk / FreeSWITCH
SIP / WebRTCHuman desk when needed
Example: Lead enters CRM → AI qualifies → workflow enriches → Asterisk calls lead → AI voice handles first conversation → qualified lead reaches human agent → CRM updates automatically. That is a complete business system.
One engineering practice across the complete product stack
Planes owned end-to-end
BusinessCRM · ERP · industry workflows
ApplicationNext.js · NestJS · Python
AILLM · Agents · RAG · Automation
Real-timeWebRTC · SIP · FreeSWITCH · Asterisk
DataPostgreSQL · Redis · Neo4j
EventsKafka · RabbitMQ · Webhooks
ObservabilityOpenTelemetry · Prometheus · Grafana
InfrastructureLinux · Docker · AWS · Azure · GCP
Quantitative + software engineering foundation
Mathematics & Statistics · Mathematics · Computer Applications · Data Analytics — credentials support the AI and data work; the homepage sells what ships.
Next step
Describe the workflow, data sources and constraints — get an architecture direction, not a generic sales script.
Describe Your Problem
DOMAINS & PROOF
Business domains shipped on one engineering practice
Insurance & telecom ERP, CCaaS/hosted PBX, hospitality (restaurant CMS, PMS, Italian guest compliance), education, membership, field service, care homes, events, sports fan apps, device license desks, capital-markets research, messaging CPaaS and AI voice—each tile links to a case study naming the domain rules and stack (Laravel, CodeIgniter, NestJS, Vue, React Native, Ionic, Android, Python, Asterisk, FreeSWITCH).
CommunityLaravel · React Native
EducationSchool ERP · CodeIgniter
PM / OpsWorkgroups · boards · docs
MembershipEvents · loyalty · PHP MVC
Hosted PBXTenants you can isolate
Custom CRM & ERP
Leads, stock, GST-style bills, purchasing, finance, HR portals and public careers on one login — for operators who outgrew five tools.
Next.jsNestJSPostgreSQLHRMS
CRM / ERP brief →
Clixxo ERP case →
Vertical SaaS & industry ops
School ERP, restaurant CMS + Android API, PMS/booking, loyalty clubs, PM/workgroups, device AMC desks, FSM marketplaces, care-home scheduling—usually Laravel, CodeIgniter or NestJS with React/Vue or mobile clients.
LaravelCodeIgniterReact NativeAndroid
School ERP case →
Restaurant platform →
All vertical products →
Domain products (regulated & markets)
Insurance agency OS, Indian-law assistant, Foliolytics portfolios, AI equity research, SandeshX messaging—APIs first, screens second. Not a broker, not legal advice, not a carrier.
InsuranceLegal AIMarketsMessaging
Domain outcomes →
Insurance ERP →
Voice plane
FreeSWITCH, Asterisk, FusionPBX — trunks, IVR, DID, failover and the carrier path, not only a dialplan.
FreeSWITCHAsteriskFusionPBXSIP
FreeSWITCH brief →
Asterisk brief →
FusionPBX brief →
VoIP / SIP brief →
AI Voice
Conversational IVR and outbound agents on a real trunk — STT, LLM tools, TTS and a transfer you can audit.
AI VoiceSTTTTSSIP
AI Voice brief →
AI voice agent case study →
AI Agents, RAG & Private AI
Agents with tools, RAG over enterprise knowledge, knowledge graphs and model serving in a VPC or on-prem — AI that writes back to the same systems voice and CRM already use.
AI AgentsRAGPrivate AIn8n
AI Agent Engineering →
AI & Data Engineering →
Private AI Architect →
CCaaS
Queues, campaigns, agent state, recordings and CRM write-back on a tenant-isolated stack.
CCaaSQueuesCRM
Contact center brief →
Mobile & Web clients
Browser softphones plus field and consumer apps on the same API — React Native (ISL, ChurchEvent), Ionic/Capacitor (Oober), native Android (Becketts), SIP.js, push and ICE/TURN that survive NAT.
WebRTCReact NativeIonicAndroid StudioLaravel API
WebRTC brief →
React SIP lab case study →
Mobile brief →
Oober mobile demo →
SaaS
Tenant isolation, provisioning, billing, white-label and RBAC — the product plane around the voice plane.
Multi-tenantBillingRBAC
SaaS brief →
APIs & data
REST, webhooks, PostgreSQL, Redis and the n8n / GHL / WhatsApp path that writes the same record the phone writes.
PostgreSQLRESTn8n
APIs brief →
AI & Workflow Automation →
Automation brief →
Identity
TLS/SRTP, tenant roles, fraud controls and HA — the isolation the SaaS admin claims has to be in the data.
TLS / SRTPRBACHA
Security brief →
Migrate
Hardware IPPBX → software/cloud, chan_sip → PJSIP, or a suite you cannot extend. Same DIDs, a cut that can roll back.
MigrationPJSIPCloud PBX
Migration outcome →
Rescue
One-way audio, dead trunks, WebRTC that dies on guest Wi-Fi — traces first, then the smallest change that restores traffic.
One-way audioSIP / RTPWebRTC
Rescue outcome →
SELECTED CASE STUDIES
Shipped platforms across operations, voice and domains
Same outcome thumbnails as the full portfolio — voice, CCaaS, ERP, insurance, markets, legal and field-service mobile. Eight featured studies below; fifteen public case studies in all.
CONFIDENTIAL PROJECT
Hebrew & Yiddish IVR Development
Hebrew, Yiddish and English recorded-prompt IVR plus Twilio safety alerts — not an LLM voice agent.
View case study →PRODUCT / INTERNAL BUILD
FreeSWITCH CCaaS — Multi-Tenant IPPBX
Super-admin tenants and FreeSWITCH sync, tenant-admin PBX and campaigns, agent SIP.js workspace — captures from the running UI.
View case study →
PRODUCT / INTERNAL BUILD
Clixxo ERP — Custom CRM & Telecom Ops
CRM, sales, inventory, purchasing, finance, telecom billing, HRMS and workflows — APIs first, screens second.
View case study →
PRODUCT / INTERNAL BUILD
Insurance ERP with WebRTC Contact Center
Quotes, DSA/agency tenancy and an agent desk with Dial — Asterisk inside the ERP. Software, not an insurer.
View case study →
PRODUCT / INTERNAL BUILD
Foliolytics — Indian share-market portfolio
Live quotes, holdings P&L, strategies and role-aware admin — FastAPI + Next.js. Software, not a broker.
View case study →
PRODUCT / INTERNAL BUILD
AI Legal Assistant for Indian Law
Jurisdiction-aware chat for BNS, BNSS, BSA and related categories — local models and admin CMS. Not legal advice.
View case study →CONFIDENTIAL PROJECT
Oober — Lawn & Snow On-Demand Platform
Marketplace SaaS — Josh admin, company ACH portal, GPS dispatch and Ionic/Capacitor apps for iOS/Android.
View case study →
WORKING SYSTEM DEMOS
Don't take the architecture claim on trust — see the working systems
45 recorded walkthroughs — CRM, ERP, insurance, legal, Indian markets, IP PBX, CCaaS, SMS CPaaS, WebRTC and mobile SaaS. Each clip shows duration, stack and what you will see on screen.
SOLUTIONS
Outcomes operators and product teams actually buy
What a buyer can point at in a search or an RFP — each outcome page names who owns SIP, media, identity and the system of record. Not sure where to start? Use Start here above or Contact.
Custom CRM & ERP
Sales, stock, GST-style billing, HR and insurance desks on one product — not a generic accounting SKU.
CRMERPHRMS
Build custom CRM / ERP →
Domain products
Legal AI, Indian-market portfolios, messaging SaaS and insights platforms — for teams who need the domain in the data model.
LegalMarketsMessaging
Build a domain product →
AI Call Center
Hybrid AI and human queues on real SIP trunks, with CRM write-back and QA on both agent types.
AI VoiceQueuesCRM
Build an AI Call Center →
Cloud PBX
Hosted extensions, IVR, recording and failover — a hardware IPPBX or locked UCaaS alternative you can inspect.
Cloud PBXIVRFailover
Build a Cloud PBX →
Multi-tenant PBX
Isolation, provisioning, billing, white-label and RBAC so you can sell hosted PBX without tenant crosstalk.
Multi-tenantBillingRBAC
Build a Multi-Tenant PBX →
VoIP Platform
APIs, number inventory, routing and an admin OS — a vertical TPaaS, not a Twilio clone for its own sake.
APIsRoutingAdmin
Build a VoIP Platform →
WebRTC Softphone
Embed browser and companion-app calling: click-to-call, push, hold/transfer and a TURN path that works off-LAN.
WebRTCSIP.jsICE / TURN
Build a Softphone →
Private AI
RAG, agents and model serving inside a VPC or on-prem — for teams that cannot paste internal knowledge into a public chatbot.
Private AIRAGAgents
Build private AI →
AI Workflow Automation
Connect AI to CRM, ERP, APIs, voice and WhatsApp—with human-in-the-loop approvals and production guardrails, not just a chatbot.
AI agentsCRM / ERPVoiceWhatsApp
Automate a workflow →
AI & Workflow Automation →
AI Voice & IVR
Real-time voice that listens, understands and acts—live transcript, natural response, DTMF fallback, CRM/API workflows and human handoff.
AI VoiceLive transcriptIVR / DTMFCRM
Build AI Voice & IVR →
Migrate
Leave a hardware IPPBX, chan_sip stack or locked suite without losing numbers, hunt groups or the week after cut-over.
MigrationPJSIPCloud PBX
Migration outcome →
Rescue
Calls are dying now. Restore traffic, name the layer, attach the proof — then monitor so Friday does not repeat.
One-way audioSIP / RTPWebRTC
Rescue outcome →
WHY CLIENTS WORK WITH ME
Architecture before code — across voice and software.
The job is an operations system you can maintain in production: CRM, ERP, voice or a domain product — not a demo that dies on the first carrier trunk.
Architecture-first
Planes, tenancy and failure modes on paper before components are chosen — then implementation follows the same drawing.
Telecom + software
One engagement across SIP/RTP/WebRTC and NestJS/Laravel/PostgreSQL — the desk and the trunk share one record.
Production experience
Real traces for one-way audio, dead trunks, ICE failures and tenant leaks — not greenfield slides.
Full-stack ownership
Frontend, APIs, data, telephony, AI tooling and deploy paths designed as one system when the product needs it.
AI in the call path
AI voice, private RAG and automation wired into queues and CRM events — not a chat widget bolted on later.
Remote engineering
Architecture, build and production support for distributed teams — Delhi base, worldwide delivery. Full biography →
HOW I WORK
A clear path from idea to production
1
Discover
Workflows, constraints, architecture review.
2
Architect
Planes, data, identity and integrations.
3
Build
App, APIs, telecom and client surfaces.
4
Integrate
SIP, AI, CRM/ERP, billing, webhooks.
5
Deploy
CI/CD, cloud/VPC/on-prem, cut-over.
6
Operate
Monitor, rescue, optimize, iterate.
ENGAGEMENT MODELS
How we can work together
Pick the shape that matches your team and stage — the first reply still names the technical plane.
Product engineering
Idea → MVP → production — product thinking, architecture and technical delivery under one roof. Service brief →
Architecture review
You have a team; you need a senior cut line, tenancy model or 90-day plan before spend accelerates.
Rescue / troubleshooting
Production FreeSWITCH, Asterisk, FusionPBX or WebRTC is failing now — traces first, smallest fix that restores traffic.
Fixed-scope project
A defined platform slice: hosted PBX tenant, CCaaS desk, CRM module, mobile app or AI voice workflow with a written deliverable.
Fractional solution architect
Startups and MSPs that need senior architecture without a full-time hire — design authority plus selective implementation.
Long-term engineering
Ongoing build for telecom or AI SaaS products — same owner from schema to SIP to deploy and incident response.
Start the brief
Name the outcome, stack and stage on the contact form — rescue uploads welcome.
Qualify your project →
FIT
When custom engineering earns its cost
Clarity on both sides — this is a consultancy for platforms and production systems, not a five-seat office PBX reseller.
You probably don’t need custom development if…
- You need a basic office PBX for a handful of users this month.
- Standard suite workflows are enough — no custom CRM or tenancy.
- You don’t need to own the platform, billing or isolation story.
- There is no integration, WebRTC desk or AI on real SIP in scope.
Custom engineering is the right move when…
- You sell PBX or CCaaS seats and need tenant isolation you can test.
- CRM/ERP, voice and mobile must share one system of record.
- WebRTC, AI voice or private RAG must live in your VPC or on-prem.
- Hardware IPPBX or chan_sip must migrate without losing DIDs.
- Production is already failing — one-way audio, trunks or ICE.
TECHNOLOGY
The stack these platforms are built on
Grouped by responsibility — core expertise first, supporting tools second, integrations where clients already pay bills. Click a badge for the matching service brief.
Integration ecosystem
Application
ReactNext.jsNestJSLaravelVueFastAPIFlaskCodeIgniterPHP
Mobile
React NativeIonicCapacitorAndroid StudioFCM push
Events & pipelines
KafkaRabbitMQWebhooksData pipelines
Data & integration
PostgreSQLRedisREST APIsCRM / ERP
Business domains
Telecom ERPInsuranceCCaaS / PBXField serviceHealthcareHospitalityEducationLegal AIMarketsMessagingCommunity
Telecom
FreeSWITCHAsteriskFusionPBXSIPRTPIVR
Real-time
WebRTCSIP.jsICE / TURNRealtime APIs
AI platforms
AI Voice — conversational IVR and agents on a real trunk. Private AI — RAG and agents in VPC or on-prem. AI Agents — tools, HITL and automation. Workflow — n8n, CRM and WhatsApp.
Observability
OpenTelemetryPrometheusGrafanaMonitoring
Security & reliability
TLS / SRTPRBACTenant isolationHA
Automation
n8nGoHighLevelZapierMakeWhatsAppHubSpot
Infrastructure
AWSGCPAzureLinuxDockerKubernetesCI/CD
Delivery
ArchitectureMigrationCI/CDDeploymentOptimization
UPWORK REVIEWS
Feedback after the work shipped
Quoted from public Upwork reviews. Older notes that mention a team are left as the client wrote them.
★★★★★
IVR & Alert System Development
Working with Pankaj has been an outstanding experience from start to finish. He consistently demonstrated exceptional professionalism, strong technical skills, and a true sense of ownership over every task.
★★★★★
Voice AI pipeline on VoIP / RTP
Pankaj delivered solid, production-grade work on the voice AI pipeline integration (VoIP, RTP, Whisper STT, Anthropic LLM, Inworld TTS). I recommend Pankaj for VoIP, real-time audio, and AI voice pipeline projects.
★★★★★
CDL Development Backend
Pankaj was highly responsive and quickly grasped the requirements for a complex digital forensics task. He delivered a thorough forensic report in multiple formats, proactively supplemented his work with additional analysis, and offered helpful guidance on tooling. Recommended for backend/forensics and data-parsing engagements.
★★★★★
ClickToBiz
Pankaj kumar joshi completed our project exactly how we instructed. Additionally, he made us aware some server updates that we needed to prevent possible problems in the future. I highly recommend him!
FROM THE BLOG
Recent writing
FreeSWITCH
One-way audio is rarely “just NAT”
How production FreeSWITCH / FusionPBX traces show whether the failure is signaling, RTP or the browser path.
Read article →09 Sep 2026
A PBX is now part of the business app
When the phone system has to live inside CRM, WhatsApp and customer workflows.
Read article →WebRTC · FusionPBX
From broken WebRTC calls to a SIP lab
How one-way audio debugging becomes a reusable diagnostic environment.
Read article →
FAQ
Questions before the first conversation
Founders hire for a spike. Companies hire to own a product. Both start on Contact — not a stacked sales script.
Scope
What kinds of projects do you take on?
AI agents and automation, RAG and knowledge systems, custom CRM/ERP, CCaaS and hosted PBX, AI voice on real SIP trunks, full-stack product engineering, vertical SaaS, migrations and production rescue. Telecom is a deep specialization inside a broader product-engineering practice.
Not only VoIP
Do you only do VoIP?
No. Voice is one plane. AI agents, RAG, CRM/ERP, Clixxo ERP, Insurance ERP, Foliolytics, the Indian-law assistant, SandeshX and Predictive Behavior eXchange are on the same practice. The bar is APIs first, screens second.
Niches
Who is this for?
Teams that need AI agents or RAG inside business systems; operators who need hosted IPPBX or multi-tenant PABX; CRM/ERP around ports, bills and HR; insurance desks next to WebRTC; CCaaS and full-stack SaaS product teams. Not a generic app mill and not a carrier.
Not a login
Is UnifiedPBX.in a hosted PBX dashboard or sign-in?
No. There is no public tenant login here. UnifiedPBX.in is the practice site. If you need hosted IPPBX software, a white-label PABX or a CCaaS built, use Contact — not a “sign in” search.
Worldwide
Do you work with teams outside India?
Yes. Delivery is remote from Delhi to operators, MSPs and product teams in any country. Time-zone overlap is agreed in the first reply. The work is the architecture and the build, not a local-only install.
Individual
Can a founder or solo engineer hire you for a short job?
Yes. Individuals hire for a bug, a spike, or to be the only VoIP engineer on a startup. Upwork and the contact form both work. Send the stack and the failure — not a 40-page RFP.
Company
Can a company hire you to build a product we resell?
Yes. Operators and MSPs hire to own hosted IPPBX, multi-tenant CCaaS or CRM+voice as their product. This is not a Zoom or Teams seat. Source, tenants and recordings stay yours. Use Contact to scope VPC, billing and isolation.
Start
How does an engagement start?
Send the current architecture, the problem, and any constraints through the contact form. The first response is a technical review, clarifying questions, and a recommended next step — not a generic sales script.
Describe your problem — get architecture direction
Share the workflow, data sources and constraints — AI agents, RAG, CRM/ERP, WebRTC, CCaaS, FreeSWITCH/Asterisk or full-stack product engineering. First reply is a technical review, worldwide.