Un error 400: Solicitud incorrecta es un código de estado HTTP que aparece cuando el servidor no puede procesar una solicitud debido a que algo no está bien con la solicitud en sí. Es un problema del lado del cliente, lo que significa que el problema proviene del navegador, la herramienta o el proxy que envía la solicitud.
Causas comunes de un error 400:
- URL no válida: Errores tipográficos, caracteres especiales o problemas de formato en la URL.
- Cookies corruptas: Las cookies caducadas o rotas pueden causar problemas.
- Cabeceras sobredimensionadas: Encabezados de solicitud que superen el límite de tamaño del servidor.
- Problemas de DNS: Problemas para resolver la dirección del sitio web.
Cómo le afecta
Un error 400 impide el acceso a una página web o un recurso, lo que puede resultar frustrante e interrumpir el flujo de trabajo. En el caso de las empresas, los errores repetidos pueden dañar la experiencia del usuario y el rendimiento del sitio.
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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?
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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?
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No. A block usually returns a 403 Forbidden. A 400 means your request itself was invalid.
Can rotating proxies cause 400 Bad Request?
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Yes, if cookies or headers are reused inconsistently between sessions.
How is 400 different from 422 Unprocessable Entity?
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400 is about malformed syntax. 422 means the syntax is fine, but the server can’t process it due to semantic errors.
