Cursor
realtime
Server-Sent Events Disconnecting in Cursor Application
Your Cursor-generated application uses Server-Sent Events (SSE) for real-time updates (live notifications, streaming responses, dashboards), but the SSE connection drops after a few seconds or minutes. Users see the real-time feed freeze, and the browser's EventSource silently reconnects only to disconnect again in a loop.
SSE connections are long-lived HTTP connections that must stay open indefinitely. This conflicts with many infrastructure components that expect short request-response cycles. Reverse proxies, load balancers, serverless platforms, and CDNs all have default timeouts that terminate SSE connections prematurely.
The issue is often intermittent — it works fine during development where there's no proxy layer, but fails in production where Nginx, Cloudflare, or a serverless platform sits between the client and server.
Error Messages You Might See
EventSource failed: net::ERR_INCOMPLETE_CHUNKED_ENCODING
EventSource connection lost, reconnecting...
504 Gateway Timeout
Error: stream timeout after 60000ms
ReadableStream has been disturbed or locked
Common Causes
- Reverse proxy timeout — Nginx, Apache, or Cloudflare terminates idle connections after 60-120 seconds by default
- Serverless function timeout — Vercel (30s), Netlify (26s), and Lambda (15min max) kill long-running functions, terminating the SSE stream
- No keep-alive heartbeat — Without periodic data sent on the connection, intermediaries assume it's dead and close it
- Missing SSE headers — The response lacks required headers like
Content-Type: text/event-stream,Cache-Control: no-cache, orConnection: keep-alive - Response buffering enabled — Nginx or Node.js response compression buffers SSE data instead of streaming it, causing events to arrive in batches or not at all
How to Fix It
- Send heartbeat comments every 15-30 seconds — Send SSE comment lines (
: heartbeat\n\n) at regular intervals to keep the connection alive through proxies and load balancers - Configure proxy timeouts — For Nginx: set
proxy_read_timeout 86400s;andproxy_buffering off;. For Cloudflare: enable WebSockets/SSE in the dashboard or use Cloudflare Tunnel - Disable response buffering — Add
X-Accel-Buffering: noheader for Nginx, and disable compression on SSE endpoints - Implement robust client reconnection — Use EventSource's built-in reconnection with a custom
retry:field, and includeLast-Event-IDhandling to resume from where the client left off - Avoid serverless for SSE — If your SSE needs long-lived connections, deploy on a traditional server (VPS, container) rather than serverless functions. Alternatively, use a managed service like Ably or Pusher
- Set correct response headers — Ensure every SSE endpoint sends:
Content-Type: text/event-stream,Cache-Control: no-cache,Connection: keep-alive
Real developers can help you.
Bastien Labelle
Full stack dev w/ 20+ years of experience
Vlad Temian
15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox).
Cursor ambassador and agentic tooling builder.
I've scaled systems, automated deployments, and built observability tools for AI coding workflows. I specialize in taking vibe-coded apps from broken prototype to production-ready: fixing Supabase auth/RLS, Stripe integrations, deployment pipelines, and cleaning up AI-generated spaghetti.
I build tools in this space (agentprobe, claudebin, micode) and understand both sides: how AI generates code and why it breaks.
https://blog.vtemian.com/
Jaime Orts-Caroff
I'm a Senior Android developer, open to work in various fields
Basel Issmail
’m a Senior Full-Stack Developer and Tech Lead with experience designing and building scalable web platforms. I work across the full development lifecycle, from translating business requirements into technical architecture to delivering reliable production systems.
My work focuses on modern web technologies, including TypeScript, Angular, Node.js, and cloud-based architectures. I enjoy solving complex technical problems and helping teams turn product ideas and prototypes into working platforms that can grow and scale.
In addition to development, I often collaborate closely with product managers, business analysts, designers, and QA teams to ensure that solutions align with both technical and business goals.
I enjoy working with startups and product teams where I can contribute both as a hands-on engineer and as a technical partner in designing and delivering impactful software.
Milan Surelia
Milan Surelia is a Mobile App Developer with 5+ years of experience crafting scalable, cross-platform apps at 7Span and Meticha. At 7Span, he engineers feature-rich Flutter apps with smooth performance and modern UI. As the Co-Founder of Meticha, he builds open-source tools and developer-focused products that solve real-world problems.
Expertise:
💡 Developing cross-platform apps using Flutter, Dart, and Jetpack Compose for Android, iOS, and Web.
🖋️ Sharing insights through technical writing, blogging, and open-source contributions.
🤝 Collaborating closely with designers, PMs, and developers to build seamless mobile experiences.
Notable Achievements:
🎯 Revamped the Vepaar app into Vepaar Store & CRM with a 2x performance boost and smoother UX.
🚀 Launched Compose101 — a Jetpack Compose starter kit to speed up Android development.
🌟 Open source contributions on Github & StackOverflow for Flutter & Dart
🎖️ Worked on improving app performance and user experience with smart solutions.
Milan is always happy to connect, work on new ideas, and explore the latest in technology.
Caio Rodrigues
I'm a full-stack developer focused on building practical and scalable web applications. My main experience is with **React, TypeScript, and modern frontend architectures**, where I prioritize clean code, component reusability, and maintainable project structures.
I have strong experience working with **dynamic forms, state management (Redux / React Hook Form), and complex data-driven interfaces**. I enjoy solving real-world problems by turning ideas into reliable software that companies can actually use in their daily operations.
Beyond coding, I care about **software quality and architecture**, following best practices for componentization, code organization, and performance optimization.
I'm also comfortable working across the stack when needed, integrating APIs, handling business logic, and helping transform prototypes into production-ready systems.
My goal is always to deliver solutions that are **simple, efficient, and genuinely useful for the people using them.**
Omar Faruk
As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience.
My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture.
I played a key role in creating a scalable and maintainable platform to support educators and learners globally.
I'm enthusiastic about embracing new challenges and making meaningful contributions.
David Olverson
Solo dev shipping production apps with AI-assisted development. I specialize in rescuing broken Lovable/Bolt/Cursor builds and taking them to production. 10+ apps shipped including SaaS CRMs, gaming platforms, real estate tools, and Discord bots. Stack: Next.js 16, TypeScript, Tailwind CSS, FastAPI, PostgreSQL, Prisma. I use Claude Code with 50+ custom skills for rapid delivery. Average turnaround: 2-4 weeks from broken prototype to production.
Pratik
SWE with 15+ years of experience building and maintaining web apps and extensive BE infrastructure
Kingsley Omage
Fullstack software engineer passionate about AI Agents, blockchain, LLMs.
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
Can I use SSE with serverless platforms like Vercel?
Standard SSE with long-lived connections doesn't work well with serverless platforms due to function execution time limits. Vercel supports streaming responses for up to 30 seconds. For longer connections, use a dedicated WebSocket service (Ably, Pusher, Supabase Realtime) or deploy the SSE endpoint on a traditional server.
How is SSE different from WebSockets?
SSE is unidirectional (server to client only), uses standard HTTP, and has built-in reconnection. WebSockets are bidirectional, use a separate protocol (ws://), and require manual reconnection logic. Use SSE when you only need server-to-client updates; use WebSockets when you need two-way communication.