Bolt
api
CORS Preflight Request Timeout - OPTIONS Request Failing
POST or other non-simple requests fail because the CORS preflight OPTIONS request times out. Browser doesn't even send the actual request.
Requests work in some browsers but not others, or fail intermittently.
Error Messages You Might See
OPTIONS request timeout
Preflight request failed
No 'Access-Control-Allow-Methods' header
CORS preflight failed
Common Causes
- Server doesn't handle OPTIONS method
- OPTIONS request takes too long to respond
- Firewall blocking OPTIONS method
- CORS headers missing in OPTIONS response
- Preflight cache too short, requesting too frequently
How to Fix It
Ensure server responds to OPTIONS: if(request.method === 'OPTIONS') return new Response(null, { status: 200, headers: corsHeaders })
Response must include CORS headers: 'Access-Control-Allow-Methods', 'Access-Control-Allow-Headers', 'Access-Control-Max-Age'
Set long max-age: 'Access-Control-Max-Age': '86400' (24 hours)
Use middleware to add CORS to all routes
Real developers can help you.
ISHANTDEEP SINGH
Senior Software Engineer with 7+ years of experience in React, JavaScript, TypeScript, Next.js, and Node.js. I’ve also worked as a tech lead for startups, owning end-to-end technical execution including architecture, development, scaling, and delivery. I bring a strong mix of hands-on coding, product thinking, and technical leadership, and I’m comfortable building products from scratch as well as improving and scaling existing systems.
MFox
Full-stack professional senior engineer (15+years). Extensive experience in software development, qa, and IP networking.
Stanislav Prigodich
15+ years building iOS and web apps at startups and enterprise companies. I want to use that experience to help builders ship real products - when something breaks, I'm here to fix it.
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.**
Meïr Ankri
Full-stack developer specializing in React / Next.js / Node.js with 6+ years of experience. I've worked across various sectors including automotive (Reezocar/Société Générale), healthcare (Medical Link SaaS), and e-commerce (Glasman). I build web apps end-to-end, from architecture to production, with a focus on scalability, performance, and code quality. I also mentor junior developers and contribute to technical decisions and code reviews.
Luca Liberati
I work on monoliths and microservices, backends and frontends, manage K8s clusters and love to design apps architecture
BurnHavoc
Been around fixing other peoples code for 20 years.
Daniel Vázquez
Software Engineer with over 10 years of experience on Startups, Government, big tech industry & consulting.
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.
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.
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
What is preflight?
Browser sends OPTIONS request to check if server allows cross-origin request. Server responds with allowed methods/headers
How long should preflight cache?
Access-Control-Max-Age: 86400 (24 hours). Longer is better - fewer OPTIONS requests
Which requests need preflight?
Non-simple: PUT, DELETE, POST with custom headers. Simple: GET, HEAD, POST with form-data