Senior Software Engineer — AI Platform
Custom AI Solutions | Remote (Brazil) | Contract Engagement
About the Role We are looking for a Senior Software Engineer to engage directly with our CTO and engineering leadership as a dedicated platform engineer on VoxaCor™ and BridgeNode™. This is not a staff augmentation role — you will have real ownership across architecture decisions, feature development, and platform reliability.
VoxaCor™ is our AI voice and SMS platform built for high-volume, real-time communication. BridgeNode™ is the open-source AI conversation framework that powers it — every product CAIS builds runs on it. You will own significant surface area across both — from AI agent orchestration and real-time voice pipelines to frontend interfaces and infrastructure.
AI-first development is core to how we build — if you haven't shipped production AI systems, this role isn't for you.
This is a contract engagement. Applicants must have a registered legal entity in Brazil to contract through. This is a firm requirement and is not negotiable.
Key Responsibilities
Build and maintain real-time AI voice pipeline components: STT, TTS, LLM orchestration, and telephony integration
Develop multi-tenant SaaS platform features across web, voice, and SMS channels
Implement AI agent workflows using Mastra orchestration and Anthropic/Gemini LLM integrations
Design and build backend services, APIs, and data models supporting high-volume production workloads
Develop frontend interfaces and progressive web app (PWA) features in React
Build platform tooling, admin interfaces, and partner-facing configuration systems
Contribute to BridgeNode™ open-source framework and VoxaCor™ proprietary feature layers
Tech Stack
Backend: Node.js, TypeScript, PostgreSQL, Docker
Frontend: React 19, TypeScript, Tailwind CSS, shadcn/ui, PWA
Voice & Telephony: Telnyx, Deepgram (STT/TTS), WebRTC, SIP
AI / LLM: Anthropic Claude, Google Gemini, Mastra orchestration
Infrastructure: Azure, GitHub Actions CI/CD, multi-tenant architecture
Compensation
Structure: Paid twice monthly in USD for work performed
On-Target Earnings: $44K–$66K USD - depending on experience
Qualifications
5+ years of full-stack engineering experience with TypeScript/Node.js and React
Production experience building and shipping AI-powered applications — not just prototypes
Hands-on experience with LLM APIs (Anthropic, OpenAI, Gemini, or equivalent) and agent orchestration
Real-time systems experience: WebSockets, streaming APIs, or telephony/voice pipelines
Strong database and API design fundamentals with PostgreSQL
Comfortable working in a multi-tenant SaaS architecture
Professional English proficiency — written and verbal communication must be clear, accurate, and effective for async collaboration with a US-based team
Able to work independently, manage your own priorities, and communicate proactively in English
Available to overlap with US Mountain/Pacific business hours for team collaboration
Registered legal entity in Brazil — required for contract engagement (not negotiable)
Strong Pluses
Experience deploying or self-hosting open-source LLMs in private or air-gapped infrastructure environments
Prior work in voice AI, telephony platforms, or real-time audio pipelines
Open-source contributions, particularly to frameworks or developer tooling
Experience with Mastra, Pipecat, or similar AI agent orchestration frameworks
Background in transportation, logistics, or dispatch software ecosystems
What We're Looking For The ideal candidate is an experienced, self-directed engineer who defaults to building. You don't need hand-holding — you read the requirements, ask the right questions, and ship. You're excited about AI not as a buzzword but because you've worked in the stack and understand what it takes to run these systems in production. You want a role where your work matters and your decisions have real impact.
Not a Fit If
You don't have direct experience shipping AI systems to production
You're looking for a short-term engagement
You don't have a registered Brazilian entity to contract through
You need heavy management oversight to stay productive
Your English is not sufficient for async written collaboration
Skills Required
- 5+ years full-stack engineering experience with TypeScript/Node.js and React
- Production experience building and shipping AI-powered applications
- Hands-on experience with LLM APIs (Anthropic, OpenAI, Gemini, or equivalent) and agent orchestration
- Real-time systems experience (WebSockets, streaming APIs, telephony/voice pipelines)
- Strong database and API design fundamentals with PostgreSQL
- Experience with Docker and containerized deployments
- Comfortable working in a multi-tenant SaaS architecture
- Professional English proficiency (written and verbal) for async collaboration
- Available to overlap with US Mountain/Pacific business hours
- Registered legal entity in Brazil to contract through (required, non-negotiable)
- Experience with Telnyx, Deepgram, WebRTC, SIP, or equivalent telephony/voice integrations
- Experience deploying or self-hosting open-source LLMs in private or air-gapped environments
- Open-source contributions, particularly to frameworks or developer tooling
- Experience with Mastra, Pipecat, or similar AI agent orchestration frameworks
- Background in transportation, logistics, or dispatch software ecosystems
What We Do
Custom AI Solutions, LLC specializes in designing and deploying emotionally intelligent, voice-first AI agents to solve complex business communication challenges. The company creates customized Intelligent Voice Agents (IVAs) that integrate seamlessly with existing systems to automate high-volume inbound and outbound calls, including scheduling and customer service. Their mission is to empower organizations across various industries, such as healthcare and transportation, with AI that functions as a trusted team member.
