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Fiverr Pro
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$
USD
I will fix cors errors and failed deployments on vercel netlify or cloudflare
Peng Zhou
About this gig
Your API works in Postman. In the browser it just fails.
That is CORS, and it is almost never what it looks like: one misconfigured header, middleware in the wrong order, or an OPTIONS request nobody answers. I find the actual cause and fix it. Not a workaround, not a browser extension, not disabled security.
WHAT I FIX
- blocked by CORS policy, no Access-Control-Allow-Origin header
- preflight request does not pass access control check, 405 on OPTIONS
- cookies or Authorization headers silently not sent
- works locally, fails once deployed, headers stripped by a proxy
- failed builds and 404s on Vercel, Netlify and Cloudflare functions
- environment variables that are missing in production
HOW I WORK
Send me the error. I reproduce it, find the root cause, and fix it in your code or as exact changes you apply yourself. Then I verify it in a real browser with the network tab open. Postman does not enforce CORS and will happily say everything is fine while your users stare at a red console.
Basic covers one error. If it turns out to be three, I tell you before touching anything. Send the error text and your hosting platform, and I will say honestly whether it is in scope.
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Get to know Peng Zhou
Peng Zhou
Java Full Stack Developer, Backend and AI Integration Engineer
- FromChina
- Member sinceJul 2026
- Avg. response time10 hours
Languages
Chinese, English, Japanese
I am a professional full-stack developer with solid undergraduate education from Huazhong University of Science and Technology.
I have rich industry working experience in Tencent, Xiaohongshu (RED) and Ping++.
My main technical stack includes Java, Spring Boot, Vue, React, Python and LLM API integration. I can build enterprise backend systems, internal efficiency platforms and AI web applications.
I will deliver clean, maintainable code and communicate efficiently to meet your business requirements.
FAQ
My API works in Postman but fails in the browser. Why?
Postman is not a browser. It talks straight to your server and ignores browser security rules. A browser enforces same-origin rules and blocks the response unless your server sends the right permission headers, so Postman succeeding tells you nothing about CORS.
Can you fix it if I cannot share repository access?
Yes. Share your config files (vercel.json, netlify.toml, nginx config, environment settings) and the response headers from the failing request. I identify the cause and send exact changes to apply. Slightly slower over messages, but it works.
Will you touch my live production site?
Only if you ask, and only after we have identified the cause. If you would rather apply changes yourself on production, I write them out and you run them. Either way is fine, just tell me your preference up front.
What if you cannot find the cause?
Then I tell you, and we close the order out properly instead of leaving it hanging. In practice, if it really is CORS or deployment configuration it is findable, and I keep asking for what I need until we have it.
Do you only work on JavaScript stacks?
No. CORS is a browser rule, not a JavaScript rule. I work on Node and Express, Java with Spring Boot, Python with FastAPI or Django, and PHP with Laravel. It makes no difference whether the code was hand-written or generated by a tool like Lovable or Bolt - the fix lands in the same layer.
How fast can you start?
A one-error fix is usually delivered within a day, often within hours if you send the error text, the failing URL and your hosting platform up front. If I cannot start immediately I will tell you before you order, not after.
Do you also fix build failures and deploy errors?
Yes, that is why the title says failed deployments too. Broken builds, 404s on serverless and edge functions, missing production environment variables and headers stripped by a proxy all sit in the same family.
What is out of scope?
I fix application-level configuration: CORS headers, preflight handling, proxy and redirect rules, environment variables, deploy configuration and function routing. I do not do server administration, network firewalls, DNS changes or platform migrations.
Can one order cover more than one error?
Basic covers one error, Standard up to three, Premium up to five. If I find your issue is really several problems, I tell you before touching anything and we adjust the order together. I never silently expand scope.
What do you need from me before ordering?
The exact error text or a console screenshot, the failing URL or endpoint, where it is hosted, your stack and framework version, and whether it ever worked. With those five things I usually fix it in hours instead of days.
