Fractional CTO / Technical Co-founder

Promoflix.ai · Remote · Part-time, 15 hours/week minimum · Equity Role
About Promoflix
Promoflix is an AI-powered platform for mass-personalized video outreach. One real recording becomes hundreds of videos that greet each recipient by name, delivered by email, LinkedIn, or SMS. Local businesses use it to win back lapsed customers and collect Google reviews; recruiters and agencies use it for outreach that gets answered. The product is built and in use by trial customers.
The role
We're looking for a technical co-founder who wants to own part of what they build. You'll be the engineer who writes, fixes, and improves the platform yourself — hands-on development, not oversight of other developers. At times some freelance help may be needed; you'll know when and how. The core product exists, so the work is quality, reliability, and making the system smarter with AI.
This is a genuine part-time role, with a minimum of 15 hours a week. It is built for someone who wants a real ownership stake in a product, not a freelance gig paid by the hour.
Our stack
The platform generates a personalized video in 3–4 minutes and is built to scale horizontally.
Backend services: Rust microservices; Python / FastAPI
Database: PostgreSQL
Video and AI: FFmpeg, OpenAI API, voice synthesis and lip-sync AI
Frontend: Next.js, React, TypeScript, Tailwind CSS (HeroUI components)
Cloud: Google Cloud Platform; considering AWS
Delivery channels: Email (Postmark), LinkedIn (Unipile), SMS
Billing: Stripe subscriptions
Integrations: Zapier and third-party APIs
Dev tooling: Cursor AI
What you'll do
Own the platform's code: build features, fix bugs, and keep it reliable and secure.
Lead a full QA pass and close the known gaps — both in the marketing, sales and onboarding flow, and in the portal and app for subscribers.
Redesign key workflows to make better use of AI and streamline the user flow, from video creation to campaign launch. Explore AI options that could deliver higher-quality output or greater efficiency.
Own delivery across email, LinkedIn and SMS: sending reputation, retry and fallback handling, delivery monitoring. Adding test delivery is an early roadmap item.
Keep the video rendering pipeline fast and cost-efficient as volume grows, including the voice synthesis and lip-sync AI.
Document the architecture and codebase so the system stays visible, organized, and easy to hand off.
Decide when a task is better given to a freelance specialist, and manage that work within a limited budget.
Must-haves
5+ years of professional software engineering, including shipping and running a production SaaS product end to end
Production experience with Rust — our backend is Rust microservices
Working fluency in Python (FastAPI) and PostgreSQL
Solid frontend skills in Next.js, React and TypeScript
Experience building reliable message delivery: retry logic, fallbacks, and delivery monitoring
Comfortable inheriting an existing codebase and improving it without rewriting it
Documents architecture and code so systems stay visible, organized, and easy to hand off
Strong pluses
Video and AI media pipelines: FFmpeg, voice synthesis, lip sync, OpenAI API
Google Cloud Platform
Stripe subscription billing
LinkedIn messaging integrations (we use Unipile) and SMS delivery
Email deliverability fundamentals (SPF, DKIM, DMARC)
Uses AI coding tools such as Cursor to move fast as a small team
Experience setting up website, marketing and sales operations systems (Make.com, Airtable, Zapier), and can provide technical support in those areas as needed
Who thrives here
Above all: you want to build value in something you partly own and benefit from, rather than punching a clock to build something for someone else's gain. Equity in a product you shape matters more to you than an hourly rate.
You think like an owner: you fix root causes, not just symptoms.
You say plainly when something isn't worth building or needs another approach.
You can reliably give 15+ hours a week alongside your other commitments.
What we offer
Co-founder equity vesting over 3 years
An early vesting tranche tied to two milestones: closing the QA and reliability gaps, and redesigning the product flow to make better use of AI
Real authority over technical decisions and, as it grows, the development budget
A move to paid hours once revenue supports it
Honest stage disclosure
We are pre-revenue with live trials and cannot pay salaries yet. The role is part-time, with a 15-hour weekly minimum. It suits someone with other income who wants a meaningful stake in an early product — not someone looking for freelance income.

Work arrangement
Yes