O que é 400 — Bad Request? (Proxies explicados)
Um erro 400 — Bad Request é um código de status HTTP que aparece quando o servidor não consegue processar uma solicitação devido a algo estar errado com a solicitação em si. É um problema do lado do cliente, o que significa que o problema vem do navegador, da ferramenta ou do proxy que está enviando a solicitação.
Causas comuns de um erro 400:
- URL inválida: Erros de digitação, caracteres especiais ou problemas de formatação na URL.
- Cookies corrompidos: Cookies expirados ou quebrados podem causar problemas.
- Cabeçalhos grandes: Solicite cabeçalhos que excedam o limite de tamanho do servidor.
- Problemas de DNS: Problemas na resolução do endereço do site.
Como isso afeta você
Um erro 400 impede que você acesse uma página da Web ou um recurso, o que pode ser frustrante e atrapalhar seu fluxo de trabalho. Para empresas, erros repetidos podem prejudicar a experiência do usuário e o desempenho do site.
What’s your use case?
Chat with one of our Data Nerds and unlock a 2GB free trial tailored to your project.
Use Cases
Web Scraping With Proxies
A malformed request body sent through a rotating proxy pool will be rejected with 400. Ensuring payload consistency is critical.
Geo-Targeted Requests
If a proxy in one region appends characters incorrectly (e.g., localized symbols), the request may break and return 400.
Browser Automation
Using headless browsers with proxies can generate 400s if session cookies aren’t synced correctly or requests aren’t fully formed.
Best Practices
Rotate Clean Sessions
Don’t rely on stale cookies. With residential or ISP proxies, start fresh sessions to avoid corrupted state leading to 400s.
Validate Before Scaling
Test requests without proxies first. Once you know the request works, scale through proxy pools.
Monitor and Log Errors
Track when 400s occur. If they spike only on certain proxy subnets, it could point to encoding or misconfiguration issues.
Implement Retry Logic Carefully
400 usually means “fix your request,” not “try again.” Avoid blind retries—diagnose and correct the malformed request.
Conclusion
A 400 Bad Request happens when the server can’t understand what was sent. For proxy users, it’s often tied to malformed headers, bad cookies, or misconfigured requests. Clearing sessions, validating requests, and checking proxy settings are the keys to fixing it.
Frequently Asked Question
Does using proxies increase the chance of 400 errors?
+
Not directly. A 400 is about malformed requests, not about being blocked. But poor proxy setup (wrong headers, broken cookies) can cause them.
Is a 400 error the same as being blocked?
+
No. A block usually returns a 403 Forbidden. A 400 means your request itself was invalid.
Can rotating proxies cause 400 Bad Request?
+
Yes, if cookies or headers are reused inconsistently between sessions.
How is 400 different from 422 Unprocessable Entity?
+
400 is about malformed syntax. 422 means the syntax is fine, but the server can’t process it due to semantic errors.
