Senior Frontend Engineer

Adapty.io; Greater London; Hybrid; GBP 90,000 - 150,000; Full time

Benefits offered by this job

Flexible remote work

London office

Belgrade office

Language learning

Health insurance

Laptop coverage

Job summary

Adapty is looking for a Senior Frontend Engineer to own the frontend of Flow Builder. You will shape architecture, collaborate with product and design, and ensure fast, scalable editor performance across multiple runtimes.

You’ll work on an editor-like product with a document model, AI-driven features, and cross-platform rendering. The role offers flexible remote work with onsite options in London or Belgrade.

Qualifications

• 5+ years shipping production web applications in React and TypeScript.
• Editor-class interfaces: canvas, drag and drop, node or graph editors, WYSIWYG, design tools.
• Think in product terms: articulate problems solved and impact.
• Owned architecture on a product that keeps growing and boundaries you drew.

Responsibilities

• Take features from a customer problem to production: decide with product and design what to build, defend the call, ship it, and check what changed after release.
• Own the architecture of the editor and move it forward as the product grows: module boundaries, document model shape, reusable components, keep editor fast as flows scale.
• Ship across the editor surface: canvas and layers, element inspector, selectable groups and states, navigation, actions, variables, and conditional logic.
• Own the layer that translates editor config into SDK execution on device; negotiate the five-runtime contract with mobile team.
• Close the gap between browser preview and device rendering across layout, typography, media, dark mode, screen sizes, and orientations.
• Build the document model underneath all: nested configs, undo/redo, autosave, drafts vs published, and concurrent editing.
• Build the product around the AI Editor so generated screens are inspectable and reversible: prompt history, per-prompt undo, and a clear view of changes.

Skills

React

TypeScript

Frontend Architecture

Editor UI

Performance

Job description

At Adapty, we make it easy for mobile apps to manage in-app purchases and paywalls. We power 20K+ apps, process $2B+ in subscriptions every year, and have been growing fast for the last four years. Our mission is simple: make apps rich.

We are a team of 210+ passionate, product-driven people who love solving big challenges. Backed by top investors like 500 Startups and Surface Ventures, we are building one of mobile's fastest-growing SaaS companies and aiming for number one worldwide.

Why This Role Matters

Flow Builder is one of Adapty's core products and the biggest bet we're making right now.

Our customers use it to assemble the screens their users see before paying: onboarding, quizzes, paywalls, and post-purchase experiences. They build multi-screen flows with branching, variables, and conditional content directly in the browser. The Adapty SDK renders those flows natively on iOS, Android, React Native, Flutter, and Capacitor, and a change published in the editor reaches users without an app release.

We're building the most capable native-rendering builder on the market, and that sets a high bar for engineering. This is an editor with the complexity of a design tool: a document model, a layer tree, layout and styling systems, a preview that has to agree with five runtimes, and an AI Editor that can rewrite the screen you're looking at from a prompt.

It's closer to Figma than to a dashboard, with subscription revenue running through every screen it renders.

We're hiring a Senior Frontend Engineer to own the frontend of Flow Builder and help shape what it becomes. You'd set architectural direction rather than pick up specced tickets, work with the SDK team on the config contract, and take features from a customer problem to production. It's a small team, with no analysts between you and the decision.

The product is public, so you can see what you'd be building before you talk to us: Adapty Flow Builder

What You’ll Do

• Take features from a customer problem to production: decide with product and design what to build, defend the call, ship it, and check what changed after release.
• Own the architecture of the editor and move it forward as the product grows: module boundaries, the shape of the document model, where reusable components live, and keeping the editor fast when a flow grows from four screens to hundreds of branches.
• Ship across the editor surface: canvas and layers, element inspector, selectable groups and states, navigation, actions, variables, and conditional logic.
• Own the layer that translates the editor config into what the SDKs execute on device. It's a contract with five runtimes, and you'll negotiate it with the mobile team.
• Close the gap between browser preview and device rendering across layout, typography, media, dark mode, screen sizes, and orientations.
• Build the document model underneath all of it: nested configs, undo and redo, autosave, drafts versus published versions, and concurrent editing.
• Build the product around the AI Editor so a generated screen is as inspectable and reversible as a hand-built one: prompt history, per-prompt undo, and a clear view of what changed.

About You

• 5+ years shipping production web applications in React and TypeScript.
• You’ve built editor-class interfaces: canvas, drag and drop, node or graph editors, WYSIWYG, design tools, page builders. Something with a document underneath, not forms over a database.
• You think in product terms. You can say what problem your last feature solved, who had it, and what changed after you shipped it.
• You’ve owned architecture on a product that kept growing. You can explain the boundaries you drew, and what you’d draw differently now.
• You’re at home in complex client state: normalized models, immutability, undo and redo, optimistic updates, versioning.
• You can own rendering and performance end to end: box model, flex, absolute positioning, reproducing a target exactly rather than approximately, and profiling before you optimize.
• You go after requirements and contracts yourself, and you say it out loud when something is wrong.

What’s in it for you

• Strong product with industry-best metrics. Adapty is among the top 5% fastest-growing SaaS companies.
• Exceptional compensation directly tied to your results.
• Direct communication and ownership. No bureaucracy, no politics, just impact.
• Flexible remote work. Join us from anywhere or work onsite in our Belgrade or London offices.
• Professional support. Language learning, sports, health insurance, laptop coverage, and more.