curlcpp: an object-oriented C++ wrapper around libcurl

A C++ object model over the libcurl C API

The README describes curlcpp as an object-oriented C++ wrapper for the cURL tool, and the repository description says the same thing more precisely, an object oriented C++ wrapper for CURL (libcurl). The audience is a C++ developer who has decided to use libcurl and finds the C interface awkward, since the C API is a long sequence of calls that pass option identifiers and void pointers.

The library is MIT licensed, and the documentation lives at a GitHub Pages site rather than in the repository. The repository itself is a CMake project with an `include` directory for the public headers, a `src` directory for the implementation, a `test` directory, and helper directories named `CMake`, `CMakeScripts` and a top-level `CMakeLists.txt`.

The object model shows through in the example code. A request is made with a `curl_easy` object, options are attached with a template call that names the libcurl macro, and failures arrive as a `curl_easy_exception` that you catch rather than as a return code you have to remember to check. The header set follows the same naming, with separate headers for the easy interface, the I/O stream helper, the form builder and the exception type.

The topics attached to the repository list libcurl, lcurlcpp-lcurl, cross-platform and network-requests, which matches a project whose job is to make an existing C library pleasant rather than to add a networking model of its own.

Building is CMake, static or shared

The build instructions cover two standalone variants. The static library is built with:

cd build
cmake ..
make

and the shared library variant adds a CMake option:

cd build
cmake .. -DBUILD_SHARED_LIBS=SHARED
make

The README states a hard version floor in bold: cURL >= 7.86.0 is required. That is a recent enough libcurl that it will rule out the version shipped with older distributions, which is a real consideration on a long-lived build image.

The linking step is where people get it wrong, and the README calls it out: when linking curlcpp to your application, do not forget to also link `curl`. The example compile line makes both libraries visible:

g++ -std=c++11 example.cpp -I/usr/local/include/curlcpp/ -lcurlcpp -lcurl 

Note the standard: the example is compiled with `-std=c++11`, which is the baseline the library's own examples target.

Homebrew is the other installation route, and it is the shortest of the three:

brew install curlcpp

Vendoring it with a submodule and add_subdirectory

For a project that prefers to vendor the dependency rather than install it system wide, the README describes the git submodule route with CMake. Two lines go into the host project's `CMakeLists.txt`:

ADD_SUBDIRECTORY(ext/curlcpp) # Change `ext/curlcpp` to a directory according to your setup
INCLUDE_DIRECTORIES(${CURLCPP_SOURCE_DIR}/include)

The comment on the first line is the practical instruction: the path has to be changed to match where the submodule was placed, and the `ext/curlcpp` in the example is a convention rather than a requirement. The second line adds the public headers to the include path using the variable the project exports.

This is the approach that avoids the libcurl version problem in a controlled way, since the submodule pins a known-good state of the wrapper, and it is also the approach that puts the vendored source in your own tree. The trade is that the version floor on libcurl itself still applies, because the wrapper is built against the system libcurl either way, and only the wrapper source is vendored.

The `CMake` and `CMakeScripts` directories at the repository root hold the pieces the build needs, and the `test` directory is where the README says more usage examples live, which is worth checking before writing your own.

Options are set with a typed template call

The mechanism that makes the wrapper feel like C++ is the `add` template. Options are set by naming the libcurl macro as a template argument, and the value type follows from the macro:

    // Easy object to handle the connection.
    curl_easy easy;

    // Add some options.
    easy.add<CURLOPT_URL>("http://<your_url_here>");
    easy.add<CURLOPT_FOLLOWLOCATION>(1L);

The value types differ between the two calls in that example, a string for the URL and a long for the follow-location flag, and that is the point. In the C API the same call takes a void pointer and the type discipline is the programmer's problem.

The rest of the shape is equally conventional. `perform()` executes the request, and it throws `curl_easy_exception` on failure, which you catch and print with `error.what()`. A `curlcpp_traceback` object holds the error stack, and `error.print_traceback()` prints the whole stack, which is the thing to reach for when a request fails and you need to know which step failed rather than just that something did.

Session information comes back through `get_info`, with a `CURLINFO_CONTENT_TYPE` call in the examples. The return is a `curl_easy_info` object whose `get` method yields a pair, the request return code and the value of the requested libcurl macro.

curl_ios is where the response body goes

The I/O helper is the most useful idea in the library, and it is what keeps response handling from turning into buffer management. The constructor takes a stream, and the easy object is built around it, so the body lands where you want it.

The README shows the pattern with a string stream, where the request output goes into a previously declared stream:

    // Let's declare a stream
    ostringstream stream;

    // We are going to put the request's output in the previously declared stream
    curl_ios<ostringstream> ios(stream);

    // Declaration of an easy object
    curl_easy easy(ios);

and with a file, where the same helper writes the response straight to disk:

    // Create a file
    ofstream myfile;
    myfile.open ("/path/to/your/file");
    
    // Create a curl_ios object to handle the stream
    curl_ios<ostream> writer(myfile);
    // Pass it to the easy constructor and watch the content returned in that file!
    curl_easy easy(writer);

Forms are assembled from curl_pair values

POST bodies that are HTML form encoded are built with the `curl_form` class, and each field is a pair of a name and a value. The README's login form example creates the pairs explicitly with the libcurl form options:

    curl_form form;
    curl_easy easy;

    // Forms creation
    curl_pair<CURLformoption,string> name_form(CURLFORM_COPYNAME,"user");
    curl_pair<CURLformoption,string> name_cont(CURLFORM_COPYCONTENTS,"you username here");
    curl_pair<CURLformoption,string> pass_form(CURLFORM_COPYNAME,"passw");
    curl_pair<CURLformoption,string> pass_cont(CURLFORM_COPYCONTENTS,"your password here");

The pairs are then added to the form and the form is attached to the request as the POST body, which is what `easy.add<CURLOPT_HTTPPOST>(form.get())` does in the same example. The naming is a little awkward because a field needs two objects, one for the name and one for the value, but it is explicit about which libcurl form option each object carries.

One detail in that example deserves a warning rather than a copy. It sets `CURLOPT_SSL_VERIFYPEER` to false on what the README calls an HTTPS POST login form, which disables server certificate verification for a request that carries a password. The README is presenting the mechanics of the form API, not a security recommendation, and that line should not survive into production code.

The error handling in the same example shows the traceback API, where `error.get_traceback()` returns the stack as a `curlcpp_traceback` object and `error.print_traceback()` writes it out.

Version 3.1 from 2023 with a branch pushed in June

The licence is MIT, with the LICENSE file at the root of the repository. There is no licence complication here beyond the standard notice requirement, and the project is usable in commercial code on MIT terms.

On maintenance, the repository is not archived and the last push was on 2026-06-28, so there is recent activity on the branch. The published releases are older: curlcpp 3.1 from 2023-04-17, curlcpp 3.0 from 2023-03-25 and curlcpp 2.1 from 2022-10-24. So a consumer of the released artefacts is more than three years behind the branch, and there is no changelog file at the top level to bridge that gap, which means the commit history is where the differences live.

The documentation lives on a separate GitHub Pages site, and the README's donate section carries a Bitcoin address link, which is the project's funding route.

One design question remains open for anyone evaluating it, and the README does not answer it: libcurl's option set is large and versioned, and a wrapper can only expose what its author implemented. The escape hatch exists, since the wrapper sits on the C API and the underlying handle is reachable, but a wrapper that is a release behind the C library it wraps is a maintenance question for whoever adopts it, not for the upstream project.

Editorial conclusion

curlcpp fits a C++ codebase that already links libcurl and wants typed options, exception based error handling and response bodies delivered into a stream without hand-managed buffers. It is the wrong choice for a project that wants the smallest possible dependency surface, since it adds a wrapper you must maintain, and the wrong choice if you need an option that the wrapper has not exposed. Verify first that your libcurl is at least 7.86.0, that the option you need is represented in the wrapper rather than reachable only through the escape hatch, and that you link both libcurlcpp and curl as the README insists.

Frequently asked questions

Official sources

1. JosephP91/curlcpp on GitHub
2. License: MIT
3. Project website
4. README
5. Releases