Hire NestJS Developers
Expert VoIP backend APIs, SIP signalling servers, and microservices. Build scalable communication infrastructure.
Quick answer
How do I hire a NestJS developer?
Share your requirements with CelloIP and get matched NestJS developer profiles within 1–2 days. Interview them, and your developer can start within a week under an NDA, with full IP ownership and a 30-day money-back guarantee. Every developer has 3+ years of hands-on experience, backed by CelloIP's 9+ years in VoIP and real-time communication.
Technology Stack
NestJS Core
API Layer
Database & ORM
VoIP Integration
Messaging & Events
Auth & Security
Developer Roles Available
Senior NestJS Backend Developer
Custom quoteNestJS, TypeScript, REST/GraphQL, PostgreSQL, Prisma, Redis, Docker
Architecture-focused backend engineer with production deployment experience
NestJS VoIP / SIP API Developer
Custom quoteFreeSWITCH ESL, Asterisk AMI, SIP gateway APIs, CDR processing, NestJS WebSocket
Specialized in real-time VoIP backend integration
NestJS Microservices Developer
Custom quoteNestJS microservices, Kafka, RabbitMQ, gRPC, distributed systems, event sourcing
Expert in high-throughput event-driven telecom architectures
NestJS + React Full-Stack Developer
Custom quoteNestJS API backend, React/Next.js frontend, tRPC, JWT auth, Stripe billing
Full-stack capability with backend excellence
Common Use Cases
VoIP Platform REST API
Comprehensive SIP user management, DID provisioning, trunk configuration, and CDR API
FreeSWITCH ESL Event Server
NestJS service consuming FreeSWITCH events for real-time call control and CDR storage
Real-Time Billing Engine
CDR ingestion, LCR rating, prepaid balance deduction with sub-100ms rating per call
SIP Trunk Provisioning API
REST API for carrier trunk management, failover routing, and capacity management
WebRTC Signalling Server
NestJS WebSocket signalling for browser-based calling — offer/answer/ICE exchange
Microservices VoIP Platform
Distributed platform with separate NestJS services for routing, billing, users, and analytics
How We Compare
| Provider | Rate | Expertise | Onboarding |
|---|---|---|---|
| CelloIP | Custom quote | NestJS + VoIP vetting | Within a week |
| Toptal | $90-180/hr | General Node.js | 2-3 weeks |
| Upwork | $15-60/hr | Self-reported skills | 1-5 days |
| Clutch Agencies | $80-150/hr | Agency-managed | 2-4 weeks |
| Fiverr Pro | $15-50/hr | Portfolio-based | 1-3 days |
Our Hiring Process
Requirements
Describe your NestJS backend or VoIP API needs
Match Developer
We find the right NestJS specialist for your project
Code Challenge
Live NestJS API development and TypeScript test
Money-Back Guarantee
Covered by our 30-day money-back guarantee for the first 30 days
Deploy Ready
Fully productive and integrated within a week
Our Guarantees
30-Day Refund
Full refund if not satisfied
48-Hour Onboarding
Productive immediately
Vetted Engineers
NestJS developers with 3+ years of hands-on experience
24-Hour Swap
Instant replacement if needed
Client Reviews & Project Outcomes
“Kaushik has delivered this project very promptly and with high accuracy … He is an excellent VOIP and Mobile Application Developer, as he delivers the project as a work of excellence.”
XMPP messaging app for Android
Verified Upwork review
“Kaushik did excellent work. Hands down the best experience I have had hiring a freelancer. Kaushik listened to my needs and exceeded my expectations.”
Android app bug fixes
Verified Upwork review
Delivered an omnichannel contact centre: inbound and outbound campaigns, WhatsApp, Instagram/Meta, email and SMS in one agent desktop, with SLA tracking and ticketing integration.
Contact centre operator
Project outcome
Frequently Asked Questions
Why use NestJS for a VoIP backend?
NestJS provides a structured, opinionated TypeScript framework with built-in dependency injection, decorators for routing and validation, and modular architecture — ideal for VoIP platforms where call control, billing, CDR processing, and user management each need clean module boundaries. It integrates natively with Socket.io for WebSocket-based AMI/ESL interfaces.
Can NestJS connect to FreeSWITCH ESL?
Yes. We use the modesl library or a custom TCP socket module in NestJS to connect to FreeSWITCH's Event Socket Layer. NestJS's module system isolates the ESL connection cleanly, and its event emitter allows other modules to subscribe to call events without tight coupling.
NestJS vs Express for a SIP API server?
NestJS is strongly preferred for complex VoIP backends: built-in validation pipes, guards for auth, interceptors for CDR logging, and OpenAPI/Swagger auto-generation. Express requires manually wiring all these. For simple single-route proxies, Express is fine; for production VoIP platforms, NestJS is the right choice.
How much does NestJS backend development cost?
A production NestJS VoIP backend API (user management, CDR, billing, SIP configuration) typically costs $10,000–$30,000. Pricing depends on the role, seniority and engagement length — share your requirements and we will send a tailored proposal.
Can NestJS handle high-throughput CDR processing?
Yes. NestJS with Kafka consumers and PostgreSQL (or ClickHouse for analytics) handles millions of CDRs per day. We use BullMQ for background rating jobs and Redis for in-flight prepaid balance management. We've built platforms handling 5M+ CDRs daily.
Does NestJS support WebRTC signalling?
Yes. NestJS's built-in WebSocket gateway (Socket.io or native ws) works perfectly for WebRTC signalling — handling offer/answer exchange and ICE candidate trickling. It pairs with STUN/TURN (coturn) for NAT traversal.
Other Specialized Roles
NestJS Development Resources
Custom Software Development
Full-stack web & mobile development
FreeSWITCH ESL with Node.js Guide
Real-time call control via Event Socket
NestJS Call Control in a VoIP Platform
FreeSWITCH ESL call control and Kubernetes deployment
Hire Node.js Developers
Node.js backend & API specialists
Hire Next.js Developers
Next.js 15 App Router specialists
Hire React.js Developers
React + WebRTC dashboard engineers
Hire FreeSWITCH Developers
FreeSWITCH ESL & media server experts
Developer FAQs & Pricing
Rates, contracts, timelines answered
Ready to Build Your NestJS Backend?
Find your NestJS expert within a week. 30-day money-back guarantee.