Real-Time Collaboration Backend Engineer (CRDT/WebSocket)

Synaps GmbH; United States; Remote; USD 140,000 - 190,000; Full time

Benefits offered by this job

Competitive compensation

Flexible, trust-based work setup

Relocation and visa support

Offsites that aren’t cringe

Device of choice

Five weeks of paid vacation

Job summary

Synaps GmbH is building a new standard for architectural design with AI. Real-time collaboration is a core part of the product, and we’re looking for an engineer who understands how shared systems actually work: room-based state, synchronization, failure recovery, and correctness under churn.

You’ll own the real-time infrastructure that powers collaborative editing, including WebSocket servers, room lifecycle, presence, reconnect and resync flows, and CRDT-based synchronization.

Qualifications

• Experience building real-time or shared-state systems.
• Comfort designing and operating stateful WebSocket services.
• Clear intuition for event ordering, consistency, and failure modes.
• Practical experience with CRDTs, or strong understanding of how they work.
• Experience running backend systems in production and debugging edge cases.

Responsibilities

• Own real-time infrastructure powering collaborative editing.
• Develop real-time WebSocket servers using PartyKit on Cloudflare.
• Design room lifecycle with ephemeral vs persistent state.
• Implement presence systems: cursors, selections, live updates.
• Handle reconnect, resync, and conflict recovery flows.
• CRDT-based synchronization development and maintenance.

Skills

Real-time systems

WebSocket services

Stateful design

CRDTs

Distributed systems

Event ordering

Tools

PartyKit

Cloudflare Workers

Durable Objects

WebSockets

CRDTs (Loro, Yjs)

React

XState

Job description

Synaps GmbH is building a new standard for architectural design with AI. Real-time collaboration is a core part of the product, and we’re looking for an engineer who understands how shared systems actually work: room-based state, synchronization, failure recovery, and correctness under churn.

You’ll own the real-time infrastructure that powers collaborative editing, including WebSocket servers, room lifecycle, presence, reconnect and resync flows, and CRDT-based synchronization.