cURL to Code Converter

Paste a cURL command and get working code in Python, JavaScript, PHP, or Go. Handles headers, request bodies, authentication, and cookies. Everything runs in your browser.

What Is cURL

cURL is a command-line tool for transferring data using various network protocols. The name stands for "Client URL" and it has been around since 1998. If you have ever worked with APIs, web services, or done any kind of web development, chances are you have used cURL or at least seen cURL examples in documentation.

The tool runs on virtually every operating system. It comes pre-installed on macOS and most Linux distributions. Windows 10 and later include it as well. Its ubiquity is why API documentation almost universally includes cURL examples for making requests.

A basic cURL command looks like this: curl https://api.example.com/data. That sends a GET request to the URL and prints the response to the terminal. Add flags to customize the request. The -X flag sets the HTTP method, -H adds headers, and -d sends a request body. These flags can be combined to construct complex API requests that include authentication tokens, custom content types, and structured data payloads.

According to the Wikipedia article on cURL, Daniel Stenberg started developing cURL in 1996, initially releasing it as httpget before renaming it to cURL in March 1998. The project has grown to support over 25 network protocols and is used by billions of devices worldwide. The cURL library (libcurl) is embedded in countless applications, from web browsers to IoT devices.

Why Convert cURL to Code

The typical developer workflow for API integration goes something like this. You read the API documentation, which provides a cURL example. You run it in the terminal to confirm it works. Then you need to write the equivalent request in your application's programming language. That translation step is where this tool saves time.

Translating cURL to code manually is tedious and error-prone. A moderately complex cURL command with five headers, an auth token, and a JSON body requires understanding the HTTP client library for your language, getting the syntax right, and making sure nothing gets lost in translation. A missing header or a slightly wrong content type can mean the difference between a working API call and a confusing 400 error.

This converter handles all of that automatically. It parses the cURL command, extracts every component (method, URL, headers, body, auth, cookies), and generates idiomatic code for your chosen language. The output uses standard libraries that professional developers actually use in production, like requests for Python and fetch for JavaScript.

Another common scenario is copying requests from browser developer tools. Chrome, Firefox, and Safari all let you right-click a network request and select "Copy as cURL." This gives you a complete cURL command with every header the browser sent. Paste that into this converter and you have working code to replicate that exact request from your application.

Supported cURL Flags

Here is a breakdown of the cURL flags this converter recognizes and how they map to code in each language.

The -X or --request flag specifies the HTTP method. Without it, cURL defaults to GET (or POST if data is provided). The converter detects this and uses the appropriate method function or parameter in the generated code.

The -H or --header flag adds request headers. Multiple -H flags can be used in a single command. The converter collects all headers into a dictionary or map structure appropriate for the target language. Common headers like Content-Type and Authorization are handled seamlessly.

The -d, --data, and --data-raw flags provide the request body. When these are present and no -X flag is specified, the method automatically becomes POST. The converter includes the body as a string in the generated code. If the Content-Type is application/json and the data is valid JSON, the Python output will use the json parameter instead of data for cleaner code.

The -u or --user flag handles HTTP basic authentication. The converter extracts the username and password (separated by a colon) and uses the appropriate auth mechanism for each language, whether that is a tuple in Python requests or a base64-encoded Authorization header in other languages.

The -b or --cookie flag sets cookies for the request. The converter adds these to the appropriate cookie handling mechanism in each language.

The -A or --user-agent flag sets the User-Agent header. This is equivalent to using -H "User-Agent: value" and is merged with other headers in the output.

Language-Specific Output Details

Each target language has its own idioms and standard libraries for HTTP requests. The converter generates code that follows the conventions of each language.

Python output uses the requests library. Headers go in a dictionary passed as the headers parameter. JSON bodies use the json parameter when appropriate, which automatically sets the Content-Type and serializes the data. Basic auth uses the auth parameter with a tuple. The generated code includes proper imports and is ready to paste into a Python script.

JavaScript output uses the fetch API, which is available in all modern browsers and in Node.js 18+. Headers are set in a Headers object or plain object. The body is passed as a string in the options parameter. For older Node.js environments, you would need node-fetch or another polyfill, but the syntax remains identical.

PHP output uses the built-in cURL extension (curl_init, curl_setopt, curl_exec), which is available in virtually every PHP installation. Headers are set as an array with CURLOPT_HTTPHEADER. The request body uses CURLOPT_POSTFIELDS. The generated code includes proper resource initialization and cleanup.

Go output uses the standard library net/http package. The code creates a request with http.NewRequest, sets headers individually, and executes it with http.DefaultClient. Error handling with if err != nil checks follows Go conventions. The body is wrapped in a strings.NewReader when present.

Common cURL Patterns

Certain cURL patterns show up repeatedly in API documentation and real-world usage. Understanding these patterns helps you work with the converter more effectively.

JSON API calls are the most common pattern. They typically include a Content-Type header set to application/json and a JSON-formatted body. The cURL command looks something like:

curl -X POST https://api.example.com/data \
  -H "Content-Type: application/json" \
  -d '{"key": "value"}'

Authenticated API calls add a Bearer token or API key in the Authorization header. Most modern APIs use Bearer token authentication:

curl https://api.example.com/me \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1..."

Form submissions use URL-encoded data, which is the default content type when using -d without specifying a Content-Type. The data looks like key=value&other=data.

File downloads and uploads involve different flags (-o for output file, -F for form file uploads) that are partially supported. The converter focuses on API request patterns since those are the primary use case for code conversion.

Background and History

The need for cURL-to-code conversion tools emerged alongside the explosion of REST APIs in the mid-2010s. As microservices architecture gained popularity and companies started offering APIs as products, the number of developers who needed to integrate with external services grew dramatically.

The Wikipedia article on cURL documents how the tool became the lingua franca of API documentation. Because cURL is available on every platform and its syntax is relatively readable, API providers standardized on cURL examples as the canonical way to demonstrate their endpoints. This created a constant need for translation since developers rarely write production code using cURL directly.

Early conversion tools were simple text-replacement scripts that handled only basic GET and POST requests. Modern converters like this one parse the full cURL syntax including quoted strings, escaped characters, multi-line commands with backslash continuation, and various flag formats. The parser needs to handle the fact that cURL flags can appear in any order, some flags take arguments and some do not, and the URL can appear anywhere in the command.

The official cURL documentation lists over 200 command-line options. No converter handles all of them because many are irrelevant to code conversion (like verbosity flags, progress meters, and connection timing options). The practical goal is supporting the flags that appear in 95% of API documentation examples and browser-copied requests.

Edge Cases and Troubleshooting

If the converter produces unexpected output, here are common issues and how to resolve them.

Multiline cURL commands using backslash continuation (the backslash at the end of each line) sometimes cause problems when copied from documentation. Make sure there is no trailing whitespace after the backslash. Some text editors add invisible characters that break the continuation. If in doubt, put the entire command on a single line.

Single quotes versus double quotes matter in cURL commands. On Unix systems, cURL commands typically use single quotes for the body and double quotes for header values. On Windows, the quoting conventions are reversed. This converter handles both styles, but mixed quoting within a single argument can cause parsing issues.

Browser-copied cURL commands often include the --compressed flag, which tells cURL to decompress the response. This flag is noted in the output but does not typically need to be replicated in code because HTTP client libraries handle decompression automatically.

Very long cURL commands from browsers might include dozens of headers that are not necessary for your use case. Headers like sec-ch-ua, sec-fetch-dest, and x-requested-with are browser-specific and can usually be removed from the generated code without affecting functionality. Focus on keeping Content-Type, Authorization, and any custom API headers.

Community Questions

These Stack Overflow discussions provide additional context on cURL parsing and HTTP client usage across languages.

• How to convert cURL command to Python requests - Detailed discussion of translating cURL flags to Python requests library parameters, with examples for common patterns.
• Convert cURL to JavaScript fetch - Explains the mapping between cURL options and the JavaScript fetch API, including headers, body, and method handling.
• How to send JSON data with cURL - Covers proper JSON body formatting in cURL commands, which is essential for getting correct conversion output.

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