Lead Full-Stack Developer

Lead Full-Stack Developer: Flutter / Firebase

DIFY | London / Hybrid | Full-Time | £36,000 + 2% Equity | Starting January 2027

DIFY is building the operating platform for driving instructors and driving schools. Since launching in March 2026, we’ve become the fastest-growing platform for ADIs and the most followed by instructors. We’re a team of three, and we’re now bringing development in-house.

We’re looking for a hands‑on Lead Full‑Stack Developer to take technical ownership of the platform. This isn’t a technical project management role. You’ll personally build, debug, integrate and ship production software, working directly with the founder, and you’ll be ultimately responsible for whether the product works, scales and ships.

Our stack

Flutter / FlutterFlow, Firebase (Firestore, Authentication, Cloud Functions, Cloud Messaging), Stripe, Twilio, OneSignal, PostHog, REST APIs, Git / GitHub, and App Store and Google Play deployment. The platform was built with external development support. Taking ownership of it internally is a major part of this role.

None of this is set in stone. If there’s a better way to build, structure or deploy DIFY, we expect you to make the case and take ownership of it.

What you’ll own

Full‑stack development. You’ll build in Flutter / FlutterFlow, writing custom Dart where FlutterFlow falls short. You’ll design Firestore data structures, write Cloud Functions, manage authentication and permissions, and take features from specification to production. You should be comfortable opening the codebase and solving problems yourself.

Backend. You’ll own the Firebase architecture: security rules, data integrity, event‑driven workflows, performance, monitoring, and separate development and production environments.

Payments. You’ll own the Stripe implementation: payments, subscriptions, webhooks, refund and cancellation logic, and potentially Stripe Connect. You should know how to integrate Stripe properly, not just drop in a pre‑built checkout.

Communications, analytics and integrations. You’ll make SMS, push notifications and booking reminders reliable through Twilio and OneSignal. You’ll instrument PostHog so funnels and product changes can be measured accurately. You’ll build resilient API and webhook integrations, and judge what should be built in‑house versus handled by a provider.

Technical ownership. You’ll document the existing architecture and review the work of external developers. You’ll set development standards, branching and release processes, improve monitoring and error reporting, and manage iOS and Android releases. We don’t expect everything to be rebuilt just because you’ve inherited it. We expect you to understand what works, change what doesn’t, and make pragmatic decisions based on what the business needs.

Product development. You’ll turn commercial requirements into shipped software: User problem → Requirement → Technical approach → Build → Test → Release → Measure. You should be willing to challenge poor product or technical decisions while staying focused on shipping.

Building the team. You’ll start by handling the handover from our external developers. This isn’t a vendor‑management role, though. You’ll be one of the main people building DIFY. As we grow, you’ll recruit and mentor developers, review code, set engineering standards and shape future architecture.

What we’re looking for

You’ll need strong practical experience with Flutter, Dart, FlutterFlow, Firebase (Firestore, Auth, Cloud Functions), REST APIs and Git, and you should have shipped and maintained production mobile apps. We’re particularly interested in people who have shipped mobile products on a Flutter and Firebase stack.

It’s strongly desirable to have experience with Stripe and webhooks, Twilio, OneSignal, PostHog, FCM, App Store Connect and Play Console, CI/CD, error monitoring, mobile security, and SaaS or marketplace products. Node.js, TypeScript, Python or other backend experience is a plus.

This isn’t for you if

Your recent experience is mainly project or delivery management, managing engineers without coding, product management, or coordinating outsourced developers. Leadership experience is valuable, but you must still be an active developer. If something breaks in production, we need someone who will investigate the code and fix it, not hand the issue to someone else.

You’ll probably suit this role if

• You enjoy building products, not just planning them.
• You can independently investigate unfamiliar systems and integrate new services quickly.
• You know when low-code makes sense and when custom code is necessary.
• You care about code quality without over-engineering an early‑stage product.
• You’re comfortable taking responsibility when something breaks.
• You want to build an engineering function rather than join one.

Compensation

• £3,000 per month / £36,000 per year.
• Salary reviewed at 6 and 12 months, then annually. Once DIFY’s net revenue (after instructor payouts) is sustained at £50,000 per month for a full quarter, salary moves to £45,000–£49,000.
• 20,000 DIFY shares/options, equivalent to 2% of DIFY’s current fully diluted pre‑seed share capital. These vest over 4 years, quarterly, with a 1‑year cliff, and are subject to normal dilution in future rounds.

Progression

For someone who shows strong hands‑on ability and can build and lead an engineering function, there’s a potential pathway to Chief Technology Officer within approximately 12 months. This depends on performance, not tenure.