Senior Full Stack Engineer

Senior Full Stack Engineer Client: US based venue intelligence platform (occupancy, foot traffic, and crowd analytics) Engagement: hourly, contracted through Flylance Location: Remote, LATAM Why This Role Exists The client has a working MVP already running in live venues, including occupancy control across 250+ events at a major US tech conference week. One engineer built essentially all of it. That is an impressive piece of solo work, and it is also the reason this role exists: the product now has to become a revenue ready v1, and a single person cannot carry a greenfield web platform, a maturing mobile app, hardware integration, and a hardened data layer at the same time. You are being brought in as the second senior engineer to take real scope off that person's plate and own it outright. This is not augmentation on a defined backlog. Half of what you build does not exist yet, and the architecture decisions you make in the first fortnight are the ones the company lives with well after this engagement closes. The Opportunity Own the build of a production web platform from an empty repository, extend a mobile app that runs on nights where the count cannot be wrong, and wire physical ID scanning hardware into a live capture flow. Three engineers total. No product committee, no ticket queue, no waiting a week for a decision. You work directly with the person who built the product and with the founder. The engagement is deliberately scoped as a sprint. The client is upfront that it may extend into a longer term role if their funding round lands, and equally upfront that they want people who are comfortable committing to the sprint as written. If you are an independent contractor who works in engagement cycles, this is a clean, well bounded piece of senior work with genuine architectural ownership attached to it. What You Will Own Web reporting platform (greenfield) Architect and build the web dashboard from scratch in React and Vite Post event analytics, data export, and compliance reporting suitable for fire marshal and capacity requirements Venue onboarding and account setup flows Counting and venue logic Extend counter logic to support criteria based splits and venue configurations spanning multiple areas Live manager views, including owner and GM perspectives, derived areas, and line tracking Applications that assemble themselves at runtime from venue configuration, where operators define their own zones, entrances, and capacity limits and the data model follows Hardware integration Integrate ID scanning into the existing capture flow, including device connectivity and the demographic data it feeds Data and cloud layer Design and harden the data layer end to end: event ingestion, aggregation, caching strategy, and reporting infrastructure Own scalable cloud architecture across GCP and Firebase Make and defend transport and protocol decisions between mobile clients, hardware, and backend How Your Work Needs to Land You reason about data lifecycles, not screens. There is real interface work here, but the difficulty sits in the data model, the caching strategy, and the async behaviour underneath it. If your strongest instinct is component composition, this is not the fit. You decide and move. Scope will shift as the team learns from live venues. Nobody is going to hand you a specification. You are expected to make the pragmatic call under a compressed clock, document it, and keep shipping. You extract context fast. Most of what you need lives in one person's head, and that person is shipping alongside you. The engineers who succeed here pull context deliberately in week one instead of waiting to be onboarded. You build for whoever inherits it. A very small team maintains this after you leave. Structure and legibility matter more here than they would on a larger team. You are steady when the product is live. Venues run on fixed nights with hard capacity limits. Something that ships broken is not an inconvenience, it is a compliance exposure for the operator. What You'll Bring Senior ownership of complete systems: Track record of building full applications from scratch and owning them through to production, including the architecture and data design decisions behind them. Experience joining a small team and delivering meaningful scope without a ramp period. Core stack: React.js in production, with Vite or comparable modern build tooling. TypeScript in a production codebase. Deep hands on experience with Firebase and Google Cloud Platform, including debugging in a cloud heavy environment where the failure is rarely on your machine. Systems and data thinking: Strong command of data lifecycles, caching, memoization, and asynchronous patterns, and the judgment to know which one a given problem actually calls for. Ability to reason about transport and protocol tradeoffs, including where live streaming approaches beat request and response and where they do not. Comfort with applications whose structure is generated at runtime from configuration rather than hardcoded. Communication and autonomy: Professional English, written and verbal, sufficient to hold architecture discussions directly with US based engineering leadership. Comfort raising blockers early across time zones rather than absorbing them quietly. Availability: Full availability aligned to the schedule above for the duration of the engagement. Reliable home office setup with backup internet and power. What Sets You Apart Hardware or embedded adjacent integration experience, particularly scanners, Bluetooth peripherals, or device connectivity Capacitor or other hybrid mobile frameworks Prior work on live operational dashboards where the data drives an immediate physical decision Compliance or regulatory reporting experience Multi tenant SaaS where customer configuration drives application behaviour Fluent use of AI development tooling such as Claude Code or Cursor to accelerate your own throughput Engagement Details Flylance handles contracting, compliance, and onboarding Possible extension into a longer term role contingent on the client's funding round, with no commitment in either direction at the outset. Please apply on the basis of the 10 week sprint as scoped. Why You'll Love Working With Us Flylance places senior Latin American engineers with US companies on engagements where the ownership is real. You are not staffed into a queue behind three layers of management. On this one you are one of three engineers on a product that is already live in venues, working directly with the person who built it. We handle contracting, compliance, and payment so you can focus on the build, and we stay in the engagement for its full duration rather than disappearing after your start date. For contractors who work in cycles, we aim to be the relationship that brings you the next one. Interested candidates should apply through Flylance. [CONFIRM: application link] Domain Full-Stack Development Locations Latin America Remote status Fully Remote About Flylance We offer you the unique opportunity to work on cutting-edge projects that push the boundaries of technology. Imagine being part of a team that's developing the next big advancement in A.I., or crafting software solutions for Fortune 500 companies. This isn't just a job; it's your chance to make a mark on the tech landscape, showcasing your skills on projects that are at the forefront of innovation. By joining us, you're not just building software; you're building a legacy. Check out our website to learn more.