Senior / Staff Software Engineer, Mobile — Core (Messaging)

OKX will be prioritising applicants who have a current right to work in Hong Kong, and do not require OKX's sponsorship of a visa.

About The Team

Own OKX's in-app messaging end to end — from a fully in-house IM engine to a messaging platform powering community chat, payments, VIP service, and user-to-agent (AI) chat for millions. The more senior you are, the more you set the technical direction others build on.

What You'll Be Doing

Build our multi-platform unified IM SDK — unify the logic core across platforms and push performance and stability as a lever for growth.

Platformize the engine — turn it into a platform that product teams build business scenarios on (community chat, payments, VIP service).

Build user-to-agent (AI) chat — the conversational AI surface on top of IM, from real-time delivery to the agent interaction experience.

Own delivery end-to-end — real-time WebSocket long-connection and offline push across overseas + China vendor channels — so messages reach users whether the app is open or not.

Push latency, reliability, and battery/memory to their limits under real production and weak-network conditions.

Build our AI-native engineering practice — design automated development workflows and harness systems (agents, evals, guardrails, CI integration) that let AI do real engineering work, while safeguarding delivery quality and efficiency.

Raise the bar through design and code review, and by making the engineers around you better.

At the Staff level: set technical direction beyond your own area and drive cross-team decisions that shape the IM platform.

What We Look For In You

Deep, hands-on experience building native iOS and/or Android — you understand the platform, not just a framework on top of it.

Experience with a cross-platform / shared business-logic layer. We build ours in Rust + UniFFI; direct Rust-on-mobile experience is a strong plus, but experience with any shared-logic approach — KMP, Flutter, or React Native — transfers well and is valued.

Fluent in at least one of: Swift / Kotlin / Rust / Objective-C / Java / JavaScript, with strong CS fundamentals.

Architecture experience with large-scale mobile apps — you've applied maintainable design patterns and own solutions from requirements through to production.

Depth in at least one layer of the messaging stack, and the ability to work across both — whether your strength is chat/feature-level UX or real-time / networking internals: WebSocket / long-connection, and/or offline push delivery across overseas + China channels (APNs, FCM, and China vendor push). Bonus if you have the depth to reason about a messaging engine from the ground up, not just consume one.

Strong mobile performance chops (memory, battery, concurrency, weak-network).

You apply AI deeply in your own engineering — not just code generation. You've built, or are driven to build, automated development workflows and harnesses that make delivery both faster and more reliable. Solid grasp of LLM fundamentals, prompt engineering, RAG, and agent concepts, with hands-on experience taking an AI pipeline from scratch to shipped — and you're excited to build user-facing conversational / agent-chat experiences too.

Comfortable with ambiguity and high scale — you've debugged problems that only appear under real production load.

Signals we value: you naturally raise the standard of teams you join, mentor without being asked, and can grow into a technical anchor for the group.

Nice-To-Haves

Built or maintained an IM / chat product, or an SDK consumed by other teams.

Experience with mini-program or dynamic/hot-update frameworks.

Crypto trading / Web3 experience.

Perks & Benefits

Competitive total compensation package

L&D programs and Education subsidy for employees' growth and development

Various team building programs and company events

Wellness and meal allowances

Comprehensive healthcare schemes for employees and dependants

Please note that Hong Kong is a group-level service hub, and OKX does not carry on a business of operating a virtual asset trading platform in Hong Kong.