---
name: "curl_easy_escape"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/curl_easy_escape"
---

# curl\_easy\_escape(3)

URL encode a string

## NAME

curl\_easy\_escape - URL encode a string

## SYNOPSIS

```
#include <curl/curl.h>
char *curl_easy_escape(CURL *curl, const char *string, int length);
```

## DESCRIPTION

This function converts the given input *string* to a URL encoded string and returns that as a new allocated string. All input characters that are not a-z, A-Z, 0-9, '-', '.', '\_' or '~' are converted to their "URL escaped" version (**%NN** where **NN** is a two-digit hexadecimal number). Although not constrained by its type, the returned string may not be altered.

If *length* is set to 0 (zero), *[curl\_easy\_escape(3)](/curl_easy_escape/3.md)* uses strlen() on the input *string* to find out the size.

You must *[curl\_free(3)](/curl_free/3.md)* the returned string when you are done with it.

## ENCODING

libcurl is typically not aware of, nor does it care about, character encodings. *[curl\_easy\_escape(3)](/curl_easy_escape/3.md)* encodes the data byte-by-byte into the URL encoded version without knowledge or care for what particular character encoding the application or the receiving server may assume that the data uses.

The caller of *[curl\_easy\_escape(3)](/curl_easy_escape/3.md)* must make sure that the data passed in to the function is encoded correctly.

## URLs

URLs are by definition *URL encoded*. To create a proper URL from a set of components that may not be URL encoded already, you cannot URL encode the entire URL string with *[curl\_easy\_escape(3)](/curl_easy_escape/3.md)*, because it then also converts colons, slashes and other symbols that you probably want untouched.

To create a proper URL from strings that are not already URL encoded, we recommend using libcurl's URL API: set the pieces with *[curl\_url\_set(3)](/curl_url_set/3.md)* and get the final correct URL with *[curl\_url\_get(3)](/curl_url_get/3.md)*.

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    char *output = curl_easy_escape(curl, "data to convert", 15);
    if(output) {
      printf("Encoded: %s\n", output);
      curl_free(output);
    }
    curl_easy_cleanup(curl);
  }
}
```

## HISTORY

Since 7.82.0, the **curl** parameter is ignored. Prior to that there was per-handle character conversion support for some old operating systems such as TPF, but it was otherwise ignored.

## AVAILABILITY

Added in curl 7.15.4

## RETURN VALUE

A pointer to a null-terminated string or NULL if it failed.

## SEE ALSO

[**curl\_easy\_unescape**(3)](/curl_easy_unescape/3.md), [**curl\_url\_get**(3)](/curl_url_get/3.md), [**curl\_url\_set**(3)](/curl_url_set/3.md)