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With a few exceptions, WinINet is a superset of WinHTTP. When you're choosing between the two, you should use WinINet unless you plan to run within a service or service-like process that requires impersonation and session isolation.
Comparison of features
| Feature | WinINet | WinHTTP |
|---|---|---|
| Credential cache. Allows all built-in applications in Windows Internet Explorer to get credentials automatically. It also allows an application running outside of Internet Explorer to prompt/specify the credentials for the server only once. From then on the requests are automatic. | yes | no |
| Credential prompting. Provides an API that allows the calling code to prompt the user for credentials. | yes | no |
| FTP | yes | no |
| Autodial/RAS support. This is legacy functionality. Use Remote Access instead. | yes | no |
| Zones. Automatic integration with Internet Explorer security zones. | yes | no |
| IDNA support. Integrated support for the IDNA RFC/Punycode. | yes | yes |
| Cookie Jar APIs. Persistent and non-persistent cookies are supported. Any application or script can use this to see the same cookies as the browser. | yes | no |
| Protected mode IE support | yes | no |
| Decompression support. Support for gzip and deflate compression scheme. | yes | yes |
| Chunked upload support. Client code must perform the chunking. | no | yes |
| SOCKS4 (SOCKS version 4) support. Doesn't include v4a. | yes | no |
| SOCKS5 (SOCKS version 5) support | no | no |
| Bidirectional send and receive | no | no |
| Overlapped I/O | no | no |
| File scheme support. Useful for proxy scripts with a file scheme. | yes | no |
| InternetOpenUrl. Simplified code to open a URL. | yes | no |
| Services support. Can be run from a service or a service account. | no | yes |
| Session isolation. Separate sessions do not impact each other. | no | yes |
| Impersonation. Supports being called while the thread is impersonating a different user. | no | yes |
Related topics
Quick decision guide
Use this flowchart to select the right HTTP client stack:
- Is your code running in a Windows service, system process, or under impersonation?
- Yes → Use WinHTTP.
- Is your code a desktop app that needs the user's Internet Options (IE) proxy settings, cookies, or credential prompts?
- Yes → Use WinINet.
- Are you writing a modern C++ desktop or UWP/WinUI app?
- Yes → Use Windows.Web.Http (C++/WinRT via Windows.Web.Http namespace).
- Are you writing a .NET application?
- Yes → Use System.Net.Http.HttpClient.
- Do you need cross-platform compatibility?
- Yes → Use libcurl or a similar portable library.
Note
When to use neither WinINet nor WinHTTP — If you are building a new application and don't require legacy Win32 integration, prefer the modern alternatives listed above. They offer simpler APIs and better async support. Some alternatives also offer additional benefits: libcurl and .NET HttpClient are cross-platform; TLS 1.3 availability depends on the underlying TLS stack and OS configuration. Reserve WinHTTP/WinINet for scenarios that specifically require Win32 service support, browser credential sharing, or deep proxy integration.
Important
Security reminder — Regardless of which HTTP stack you choose, never disable TLS certificate validation in production. Both WinHTTP and WinINet allow ignoring certificate errors via flags, but doing so exposes your application to man-in-the-middle attacks.