Senior Software Engineer - AI First, Full Stack

Senior Software Engineer — AI Platform Custom AI Solutions | Remote (Brazil) | Contract EngagementAbout 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 ResponsibilitiesBuild and maintain real-time AI voice pipeline components: STT, TTS, LLM orchestration, and telephony integrationDevelop multi-tenant SaaS platform features across web, voice, and SMS channelsImplement AI agent workflows using Mastra orchestration and Anthropic/Gemini LLM integrationsDesign and build backend services, APIs, and data models supporting high-volume production workloadsDevelop frontend interfaces and progressive web app (PWA) features in ReactBuild platform tooling, admin interfaces, and partner-facing configuration systemsContribute to BridgeNode™ open-source framework and VoxaCor™ proprietary feature layersTech StackBackend: Node.js, TypeScript, PostgreSQL, DockerFrontend: React 19, TypeScript, Tailwind CSS, shadcn/ui, PWAVoice & Telephony: Telnyx, Deepgram (STT/TTS), WebRTC, SIPAI / LLM: Anthropic Claude, Google Gemini, Mastra orchestrationInfrastructure: Azure, GitHub Actions CI/CD, multi-tenant architectureCompensationStructure: Paid twice monthly in USD for work performedOn-Target Earnings: $44K–$66K USD - depending on experienceQualifications5+ years of full-stack engineering experience with TypeScript/Node.js and ReactProduction experience building and shipping AI-powered applications — not just prototypesHands-on experience with LLM APIs (Anthropic, OpenAI, Gemini, or equivalent) and agent orchestrationReal-time systems experience: WebSockets, streaming APIs, or telephony/voice pipelinesStrong database and API design fundamentals with PostgreSQLComfortable working in a multi-tenant SaaS architectureProfessional English proficiency — written and verbal communication must be clear, accurate, and effective for async collaboration with a US-based teamAble to work independently, manage your own priorities, and communicate proactively in EnglishAvailable to overlap with US Mountain/Pacific business hours for team collaborationRegistered legal entity in Brazil — required for contract engagement (not negotiable)Strong PlusesExperience deploying or self-hosting open-source LLMs in private or air-gapped infrastructure environmentsPrior work in voice AI, telephony platforms, or real-time audio pipelinesOpen-source contributions, particularly to frameworks or developer toolingExperience with Mastra, Pipecat, or similar AI agent orchestration frameworksBackground in transportation, logistics, or dispatch software ecosystemsWhat 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 IfYou don't have direct experience shipping AI systems to productionYou're looking for a short-term engagementYou don't have a registered Brazilian entity to contract throughYou need heavy management oversight to stay productiveYour English is not sufficient for async written collaborationOriginally posted on Himalayas