⚡ A fast, async, resource-friendly link checker written in Rust.\ Finds broken hyperlinks and mail addresses inside Markdown, HTML, reStructuredText, or any other text file or website!

Available as a CLI utility and as a GitHub Action: lycheeverse/lychee-action.

Features

This comparison is made on a best-effort basis. Please create a PR to fix outdated information. use

	lychee	awesome_bot	muffet	broken-link-checker	linkinator	linkchecker	markdown-link-check	fink
Language	Rust	Ruby	Go	JS	TypeScript	Python	JS	PHP
Async/Parallel
JSON output						1
Static binary						️
Markdown files							️
HTML files
Text files
Website support
Chunked encodings
GZIP compression
Basic Auth
Custom user agent
Relative URLs
Skip relative URLs
Include patterns	️
Exclude patterns
Handle redirects
Ignore insecure SSL
File globbing
Limit scheme
Custom headers
Summary
HEAD requests
Colored output
Filter status code
Custom timeout
E-mail links
Progress bar
Retry and backoff
Skip private domains
Use as library
Quiet mode
Config file
Recursion
Amazing lychee logo

¹ Other machine-readable formats like CSV are supported.

Contributing to lychee

We'd be thankful for any contribution.
We try to keep the issue-tracker up-to-date so you can quickly find a task to work on.

Try one of these links to get started:

• good first issues
• help wanted

Using the Commandline Client

You can run lychee directly from the commandline.

Installation

Using cargo

cargo install lychee

Using the official Docker image

docker pull lycheeverse/lychee

Using pre-built binaries

We provide binaries for Linux, macOS, and Windows for every release.
You can download them from the releases page.

Commandline usage

Run it inside a repository with a README.md:

lychee

You can also specify various types of inputs:

# check links on a website:
lychee https://endler.dev/

# check links in a remote file:
lychee https://raw.githubusercontent.com/lycheeverse/lychee/master/README.md

# check links in local file(s):
lychee README.md
lychee test.html info.txt

# check links in local files (by shell glob):
lychee ~/projects/*/README.md

# check links in local files (lychee supports advanced globbing and ~ expansion):
lychee "~/projects/big_project/**/README.*"
# ignore case when globbing and check result for each link:
lychee --glob-ignore-case --verbose "~/projects/**/[r]eadme.*"

GitHub token

Optionally, to avoid getting rate-limited while checking GitHub links, you can set an environment variable with your Github token like so GITHUB_TOKEN=xxxx, or use the --github-token CLI option. It can also be set in the config file.

The token can be generated in your GitHub account settings page. A personal token with no extra permissions is enough to be able to check public repos links.

Commandline Parameters

There is an extensive list of commandline parameters to customize the behavior, see below for a full list.

USAGE:
    lychee [FLAGS] [OPTIONS] [--] [inputs]...

FLAGS:
    -E, --exclude-all-private    Exclude all private IPs from checking. Equivalent to `--exclude-private --exclude-link-
                                 local --exclude-loopback`
        --exclude-link-local     Exclude link-local IP address range from checking
        --exclude-loopback       Exclude loopback IP address range from checking
        --exclude-mail           Exclude all mail addresses from checking
        --exclude-private        Exclude private IP address ranges from checking
        --glob-ignore-case       Ignore case when expanding filesystem path glob inputs
        --help                   Prints help information
    -i, --insecure               Proceed for server connections considered insecure (invalid TLS)
    -n, --no-progress            Do not show progress bar. This is recommended for non-interactive shells (e.g. for
                                 continuous integration)
        --skip-missing           Skip missing input files (default is to error if they don't exist)
    -V, --version                Prints version information
    -v, --verbose                Verbose program output

OPTIONS:
    -a, --accept <accept>                      Comma-separated list of accepted status codes for valid links
    -b, --base-url <base-url>                  Base URL to check relative URLs
        --basic-auth <basic-auth>              Basic authentication support. E.g. `username:password`
    -c, --config <config-file>                 Configuration file to use [default: ./lychee.toml]
        --exclude <exclude>...                 Exclude URLs from checking (supports regex)
    -f, --format <format>                      Output file format of status report (json, string) [default: string]
        --github-token <github-token>          GitHub API token to use when checking github.com links, to avoid rate
                                               limiting [env: GITHUB_TOKEN=]
    -h, --headers <headers>...                 Custom request headers
        --include <include>...                 URLs to check (supports regex). Has preference over all excludes
        --max-concurrency <max-concurrency>    Maximum number of concurrent network requests [default: 128]
    -m, --max-redirects <max-redirects>        Maximum number of allowed redirects [default: 10]
    -X, --method <method>                      Request method [default: get]
    -o, --output <output>                      Output file of status report
    -s, --scheme <scheme>                      Only test links with the given scheme (e.g. https)
    -T, --threads <threads>                    Number of threads to utilize. Defaults to number of cores available to
                                               the system
    -t, --timeout <timeout>                    Website timeout from connect to response finished [default: 20]
    -u, --user-agent <user-agent>              User agent [default: lychee/0.6.0]

ARGS:
    <inputs>...    The inputs (where to get links to check from). These can be: files (e.g. `README.md`), file globs
                   (e.g. `"~/git/*/README.md"`), remote URLs (e.g. `https://example.org/README.md`) or standard
                   input (`-`). Prefix with `--` to separate inputs from options that allow multiple arguments
                   [default: README.md]

Exit codes

• 0 for success (all links checked successfully or excluded/skipped as configured)
• 1 for missing inputs and any unexpected runtime failures or config errors
• 2 for link check failures (if any non-excluded link failed the check)

Library usage

You can use lychee as a library for your own projects. Here is a "hello world" example:

use lychee_lib::Result;

#[tokio::main]
async fn main() -> Result<()> {
  let response = lychee_lib::check("https://github.com/lycheeverse/lychee").await?;
  println!("{}", response);
  Ok(())
}

This is equivalent to the following snippet, in which we build our own client:

use lychee_lib::{ClientBuilder, Result, Status};

#[tokio::main]
async fn main() -> Result<()> {
  let client = ClientBuilder::default().build()?;
  let response = client.check("https://github.com/lycheeverse/lychee").await?;
  assert!(response.status().is_success());
  Ok(())
}

The client builder is very customizable:

let client = lychee_lib::ClientBuilder::default()
    .includes(includes)
    .excludes(excludes)
    .max_redirects(cfg.max_redirects)
    .user_agent(cfg.user_agent)
    .allow_insecure(cfg.insecure)
    .custom_headers(headers)
    .method(method)
    .timeout(timeout)
    .verbose(cfg.verbose)
    .github_token(cfg.github_token)
    .scheme(cfg.scheme)
    .accepted(accepted)
    .build()?;

All options that you set will be used for all link checks. See the builder documentation for all options.

GitHub Action usage

A GitHub Action that uses lychee is available as a separate repository: lycheeverse/lychee-action which includes usage instructions.

Troubleshooting and workarounds

We collect a list of common workarounds for various websites in our troubleshooting guide.

Users

• https://github.com/pawroman/links
• https://github.com/analysis-tools-dev/static-analysis
• https://github.com/analysis-tools-dev/dynamic-analysis
• https://github.com/mre/idiomatic-rust
• https://github.com/lycheeverse/lychee (yes, the lychee docs are checked with lychee 🤯)

If you are using lychee for your project, we'd be delighted to hear about it.

License

lychee is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Credits

The first prototype of lychee was built in episode 10 of Hello Rust. Thanks to all Github- and Patreon sponsors for supporting the development since the beginning. Also, thanks to all the great contributors who have since made this project more mature.