Bolt deployment

Vercel Serverless Function Timeout - API Routes Taking Too Long

API routes that work fine locally timeout on Vercel. Long-running tasks like file processing, bulk database operations, or external API calls exceed the timeout limit.

Requests return 504 Gateway Timeout and logs show the function was killed.

Error Messages You Might See

504 - Gateway Timeout FETCH_ERROR: request timeout Function timeout after 30s Vercel Serverless Function Error: timed out
504 - Gateway TimeoutFETCH_ERROR: request timeoutFunction timeout after 30sVercel Serverless Function Error: timed out

Common Causes

  1. Function execution time exceeds timeout (default 30s, max 60s on Pro)
  2. Waiting for slow external API calls without timeout
  3. Database query not optimized or hitting connection limits
  4. Large file processing happening synchronously
  5. Missing async/await causing hanging requests

How to Fix It

Upgrade to Vercel Pro for 60s limit (free tier is 30s max)

Add timeout to external calls: fetch(url, { timeout: 10000 })

Use background jobs for long tasks - trigger async processing, return immediately

Optimize DB queries: add indexes, use pagination for large result sets

Consider moving heavy lifting to cron jobs or separate worker services

Real developers can help you.

Matthew Jordan Matthew Jordan I've been working at a large software company named Kainos for 2 years, and mainly specialise in Platform Engineering. I regularly enjoy working on software products outside of work, and I'm a huge fan of game development using Unity. I personally enjoy Python & C# in my spare time, but I also specialise in multiple different platform-related technologies from my day job. rayush33 rayush33 JavaScript (React.js, React Native, Node.js) Developer with demonstrated industry experience of 4+ years, actively looking for opportunities to hone my skills as well as help small-scale business owners with solutions to technical problems Omar Faruk 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. Matt Butler Matt Butler Software Engineer @ AWS Taufan Taufan I’m a product-focused engineer and tech leader who builds scalable systems and turns ideas into production-ready platforms. Over the past years, I’ve worked across startups and fast-moving teams, leading backend architecture, improving system reliability, and shipping products used by thousands of users. My strength is not just writing code — but connecting product vision, technical execution, and business impact. Anthony Akpan Anthony Akpan Developer with 8 years of experience building softwares fro startups Kingsley Omage Kingsley Omage Fullstack software engineer passionate about AI Agents, blockchain, LLMs. MFox MFox Full-stack professional senior engineer (15+years). Extensive experience in software development, qa, and IP networking. Milan Surelia 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. Bastien Labelle Bastien Labelle Full stack dev w/ 20+ years of experience

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Frequently Asked Questions

What's the maximum timeout on Vercel?

Free: 30s. Pro: 60s. Enterprise: up to 5min

How do I handle long-running tasks?

Trigger them asynchronously. Save a job record to DB, return immediately, process in background

Should I wait for all async tasks?

No! Return response to user, then run cleanup/processing. Use background jobs for long tasks

Related Bolt Issues

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