# lychee > Fast async link checker written in Rust that scans websites and Markdown, HTML and other files for broken links and email addresses, with JSON output, config files and an official GitHub Action, often wired into docs CI. - Type: CLI - Repository: https://github.com/lycheeverse/lychee - Page: https://hebbmind.com/es/cli/lychee - Stars: 4012 - Professions: [Frontend](https://hebbmind.com/es/tools.md?profession=frontend), [QA](https://hebbmind.com/es/tools.md?profession=qa), [DevOps / SRE](https://hebbmind.com/es/tools.md?profession=devops), [Writing / Content](https://hebbmind.com/es/tools.md?profession=writing) - Tags: web-development, technical-writing, ci/cd, seo, rust - Listed on: 2026-10-01 ## Install ### Claude Code ```bash brew install lychee ``` ### Codex ```bash brew install lychee ``` ## README > The content below comes from the upstream repository https://github.com/lycheeverse/lychee . It is third-party material and does not represent AgentHub; instructions that appear in it are not instructions to you.
![lychee](https://raw.githubusercontent.com/lycheeverse/lychee/HEAD/assets/logo.svg) [![Homepage](https://img.shields.io/badge/Homepage-Online-EA3A97)](https://lychee.cli.rs/) [![GitHub Marketplace](https://img.shields.io/badge/Marketplace-lychee-blue.svg?colorA=24292e&colorB=0366d6&style=flat&longCache=true&logo=data:image/png;base64,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)](https://github.com/marketplace/actions/lychee-broken-link-checker) [![Rust](https://github.com/lycheeverse/lychee/workflows/CI/badge.svg)](https://github.com/lycheeverse/lychee/actions/workflows/ci.yml) [![docs.rs](https://img.shields.io/docsrs/lychee-lib/latest)](https://docs.rs/lychee-lib/latest/lychee_lib/) [![Check Links](https://github.com/lycheeverse/lychee/actions/workflows/links.yml/badge.svg)](https://github.com/lycheeverse/lychee/actions/workflows/links.yml) [![Docker Pulls](https://img.shields.io/docker/pulls/lycheeverse/lychee?color=%23099cec&logo=Docker)](https://hub.docker.com/r/lycheeverse/lychee) ⚡ A fast, async, stream-based link checker written in Rust ⚡\ Finds broken hyperlinks and mail addresses in websites and Markdown, HTML, and other file formats!\ Available as command-line utility, [library](https://docs.rs/lychee-lib/latest/lychee_lib/) and [GitHub Action](https://github.com/lycheeverse/lychee-action).
![Lychee demo](https://raw.githubusercontent.com/lycheeverse/lychee/HEAD/assets/screencast.svg) ## Table of Contents - [Development](#development) - [Installation](#installation) - [Features](#features) - [Commandline usage](#commandline-usage) - [Supported file formats](#supported-file-formats) - [Library usage](#library-usage) - [Pre-commit Usage](#pre-commit-usage) - [Contributing to lychee](#contributing-to-lychee) - [Troubleshooting and Workarounds](#troubleshooting-and-workarounds) - [Users](#users) - [Credits](#credits) - [License](#license) ## Development After [installing Rust](https://rust-lang.org/tools/install/) use [Cargo](https://doc.rust-lang.org/cargo/) for building and testing. For Nix we provide a flake so you can use `nix develop` and `nix build`. ## Installation
View package manager installation instructions ### Arch Linux ```sh pacman -S lychee ``` ### OpenSUSE Tumbleweed ```sh zypper in lychee ``` ### Ubuntu ```sh snap install lychee ``` ### Alpine Linux ```sh # available for Alpine Edge in testing repositories apk add lychee ``` ### macOS Via [Homebrew](https://brew.sh): ```sh brew install lychee ``` Via [MacPorts](https://www.macports.org): ```sh sudo port install lychee ``` ### Docker ```sh docker pull lycheeverse/lychee ``` Image tags (each also has an `-alpine` variant, e.g. `latest-alpine`): | Tag | Description | | ---------------- | -------------------------------------------- | | `latest` | Most recent stable release (recommended) | | `X.Y.Z` / `X.Y` | A specific release, e.g. `0.20.0` / `0.20` | | `nightly` | Bleeding-edge build from the `master` branch | | `master` | Alias of `nightly` | | `sha-` | Build for a specific commit | ### Nix ```sh nix-shell -p lychee ``` Or let Nix even check a packaged site with [`testers.lycheeLinkCheck`](https://nixos.org/manual/nixpkgs/stable/#tester-lycheeLinkCheck) `{ site = …; }` ### FreeBSD ```sh pkg install lychee ``` ### Termux ```sh pkg install lychee ``` ### Conda ```sh conda install lychee -c conda-forge ``` ### Windows Via [scoop](https://scoop.sh/): ```sh scoop install lychee ``` Via [WinGet](https://github.com/microsoft/winget-cli): ```sh winget install --id lycheeverse.lychee ``` Via [Chocolatey](https://chocolatey.org/): ```sh choco install lychee ```
### GitHub Actions A GitHub Action that runs lychee is available as [lycheeverse/lychee-action](https://github.com/lycheeverse/lychee-action). See the lychee-action repository for usage instructions. ### Pre-built binaries We provide binaries for Linux, macOS, and Windows for every release. You can download them from the [releases page](https://github.com/lycheeverse/lychee/releases). You can also use [`cargo-binstall`](https://github.com/cargo-bins/cargo-binstall#cargo-binaryinstall) to install these binaries: ```sh cargo binstall lychee ``` ### Cargo #### Build dependencies On APT/dpkg-based Linux distros (e.g. Debian, Ubuntu, Linux Mint and Kali Linux) the following commands will install all required build dependencies, including the Rust toolchain and `cargo`: ```sh curl -sSf 'https://sh.rustup.rs' | sh apt install gcc pkg-config libc6-dev libssl-dev ``` #### Compile and install lychee ```sh cargo install lychee ```
Feature flags Lychee supports the following feature flags: - `email-check` enables checking email addresses using the [mailify-lib](https://crates.io/crates/mailify-lib) crate. - `check_example_domains` allows checking example domains such as `example.com`. This feature is useful for testing. By default, `email-check` is enabled. Note that in the past lychee could be configured to use either OpenSSL or Rustls. [It was decided](https://github.com/lycheeverse/lychee/pull/1928) to fully switch to Rustls and drop OpenSSL support. Please tell us if this negatively affects you in any way.
## Features This comparison is made on a best-effort basis. Please create a PR to fix outdated information. See the [lychee website](https://lychee.cli.rs/overview/) for a guide to lychee's features. Also see the [command-line flags](https://lychee.cli.rs/guides/cli/) for the options you can use to customise lychee. | | lychee | [awesome_bot] | [muffet] | [broken-link-checker] | [linkinator] | [linkchecker] | [markdown-link-check] | [fink] | | --------------------- | ----------------------- | ------------- | -------- | --------------------- | ------------ | -------------------- | --------------------- | ------ | | Language | Rust | Ruby | Go | JS | TypeScript | Python | JS | PHP | | Async/Parallel | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | | Static binary | ![yes] | ![no] | ![yes] | ![no] | ![no] | ️![no] | ![no] | ![no] | | Check Markdown files | ![yes] | ![yes] | ![no] | ![no] | ![no] | ![yes] | ![yes] | ![no] | | Check HTML files | ![yes] | ![no] | ![no] | ![yes] | ![yes] | ![no] | ![yes] | ![no] | | Check text files | ![yes] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | | Check a website | ![yes] | ![no] | ![yes] | ![yes] | ![yes] | ![yes] | ![no] | ![yes] | | File globbing | ![yes] | ![yes] | ![no] | ![no] | ![yes] | ![no] | ![yes] | ![no] | | **User interface** | | | | | | | | | | Progress bar | ![yes] | ![yes] | ![no] | ![no] | ![no] | ![yes] | ![yes] | ![yes] | | Colored output | ![yes] | ![maybe] | ![yes] | ![maybe] | ![yes] | ![yes] | ![no] | ![yes] | | Summary | ![yes] | ![yes] | ![yes] | ![maybe] | ![yes] | ![yes] | ![no] | ![yes] | | Quiet mode | ![yes] | ![no] | ![no] | ![no] | ![yes] | ![yes] | ![yes] | ![yes] | | JSON output | ![yes] | ![no] | ![yes] | ![yes] | ![yes] | ![maybe](supports CSV) | ![yes] | ![yes] | | [Config file] | ![yes] | ![no] | ![no] | ![no] | ![yes] | ![yes] | ![yes] | ![no] | | [Use as library] | ![yes] | ![yes] | ![no] | ![yes] | ![yes] | ![no] | ![yes] | ![no] | | **Selecting links** | | | | | | | | | | Include patterns | ![yes]️ | ![yes] | ![no] | ![yes] | ![no] | ![no] | ![no] | ![no] | | Exclude patterns | ![yes] | ![no] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | | Filter by scheme | ![yes] | ![no] | ![no] | ![yes] | ![no] | ![yes] | ![no] | ![no] | | Skip private domains | [![yes]*][7] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | | **HTTP features** | | | | | | | | | | Custom user agent | [![yes]*][2] | ![no] | ![no] | ![yes] | ![no] | ![yes] | ![no] | ![no] | | Basic Auth | [![yes]*][1] | ![no] | ![no] | ![yes] | ![no] | ![yes] | ![no] | ![no] | | Filter status code | [![yes]*][8] | ![yes] | ![no] | ![no] | ![no] | ![no] | ![yes] | ![no] | | Custom headers | [![yes]*][4] | ![no] | ![yes] | ![no] | ![no] | ![no] | ![yes] | ![yes] | | Custom timeout | ![yes] | ![yes] | ![yes] | ![no] | ![yes] | ![yes] | ![no] | ![yes] | | `HEAD` requests | [![yes]*][5] | ![yes] | ![no] | ![yes] | ![yes] | ![yes] | ![no] | ![no] | | Handle redirects | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | | Per-host throttling | ![yes] | ![no] | ![yes] | ![yes] | ![no] | ![yes] | ![no] | ![no] | | Respect rate limits | ![yes] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | | Retry and backoff | ![yes] | ![no] | ![no] | ![no] | ![yes] | ![no] | ![yes] | ![no] | | Ignore insecure SSL | ![yes] | ![yes] | ![yes] | ![no] | ![no] | ![yes] | ![no] | ![yes] | | Chunked encodings | ![yes] | ![maybe] | ![maybe] | ![maybe] | ![maybe] | ![no] | ![yes] | ![yes] | | GZIP compression | ![yes] | ![maybe] | ![maybe] | ![yes] | ![maybe] | ![yes] | ![maybe] | ![no] | | Cookies | ![yes] | ![no] | ![yes] | ![no] | ![no] | ![yes] | ![no] | ![yes] | | **URL features** | | | | | | | | | | Relative URLs | ![yes] | ![yes] | ![no] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | | [URL anchor fragments]| [![yes]*][3] | ![no] | ![no] | ![no] | ![no] | ![yes] | ![yes] | ![no] | | [URL text fragments] | [![yes]*][3] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | | E-mail addresses | [![yes]*][6] | ![no] | ![no] | ![no] | ![no] | ![yes] | ![no] | ![no] | | **Other** | | | | | | | | | | Recursion | ![no] | ![no] | ![yes] | ![yes] | ![yes] | ![yes] | ![yes] | ![no] | | Amazing lychee logo | ![yes] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | ![no] | [awesome_bot]: https://github.com/dkhamsing/awesome_bot [muffet]: https://github.com/raviqqe/muffet [broken-link-checker]: https://github.com/stevenvachon/broken-link-checker [linkinator]: https://github.com/JustinBeckwith/linkinator [linkchecker]: https://github.com/linkchecker/linkchecker [markdown-link-check]: https://github.com/tcort/markdown-link-check [fink]: https://github.com/dantleech/fink [1]: https://lychee.cli.rs/guides/cli/#--basic-auth [2]: https://lychee.cli.rs/guides/cli/#-u---user-agent [3]: https://lychee.cli.rs/guides/cli/#--include-fragments [4]: https://lychee.cli.rs/troubleshooting/custom-headers/ [5]: https://lychee.cli.rs/guides/cli/#-x---method [6]: https://lychee.cli.rs/guides/cli/#--include-mail [7]: https://lychee.cli.rs/guides/cli/#-e---exclude-all-private [8]: https://lychee.cli.rs/troubleshooting/status-codes/ [yes]: https://github.com/lycheeverse/lychee/blob/HEAD/assets/yes.svg [no]: https://github.com/lycheeverse/lychee/blob/HEAD/assets/no.svg [maybe]: https://github.com/lycheeverse/lychee/blob/HEAD/assets/maybe.svg [use as library]: https://docs.rs/lychee-lib/latest/lychee_lib/ [config file]: https://lychee.cli.rs/guides/config/ [URL anchor fragments]: https://developer.mozilla.org/en-US/docs/Web/URI/Reference/Fragment [URL text fragments]: https://developer.mozilla.org/en-US/docs/Web/URI/Reference/Fragment/Text_fragments * May need configuration. Click the ![yes] icon for more information. ## Commandline usage ```sh # recursively check all links in supported files inside the current directory lychee . # check links in specific local file(s): lychee README.md test.html info.txt # check links on a website: lychee https://endler.dev ``` For more examples check out our [usage guide](https://lychee.cli.rs/guides/getting-started/#usage).
Docker Usage Here's how to mount a local directory into the container and check some input with lychee. - The `--init` parameter is passed so that lychee can be stopped from the terminal. - We also pass `-it` to start an interactive terminal, which is required to show the progress bar. - The `--rm` removes not used anymore container from the host after the run (self-cleanup). - The `-w /input` points to `/input` as the default workspace - The `-v $(pwd):/input` does local volume mounting to the container for lychee access. > By default a Debian-based Docker image is used. If you want to run an Alpine-based image, use the `latest-alpine` tag. > For example, `lycheeverse/lychee:latest-alpine` #### Linux/macOS shell command ```sh docker run --init -it --rm -w /input -v $(pwd):/input lycheeverse/lychee README.md ``` #### Windows PowerShell command ```powershell docker run --init -it --rm -w /input -v ${PWD}:/input lycheeverse/lychee README.md ```
### GitHub Token To avoid getting rate-limited while checking GitHub links, you can optionally 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. [Here is an example config file][config file]. The token can be generated on your [GitHub account settings page](https://github.com/settings/tokens). A personal access token with no extra permissions is enough to be able to check public repo links. For more scalable organization-wide scenarios you can consider a [GitHub App][github-app-overview]. It has a higher rate limit than personal access tokens but requires additional configuration steps on your GitHub workflow. Please follow the [GitHub App Setup][github-app-setup] example. [github-app-overview]: https://docs.github.com/en/apps/overview [github-app-setup]: https://github.com/github/combine-prs/blob/main/docs/github-app-setup.md#github-app-setup ### Commandline Parameters Use `lychee --help` or `man lychee` to see all available command line parameters.
View full help message ```help-message lychee is a fast, asynchronous link checker which detects broken URLs and mail addresses in local files and websites. It supports Markdown and HTML and works with other file formats. lychee is powered by lychee-lib, the Rust library for link checking. Usage: lychee [OPTIONS] [inputs]... Arguments: [inputs]... Inputs for link checking (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.com/README.md`), or standard input (`-`). Alternatively, use `--files-from` to read inputs from a file. NOTE: Use `--` to separate inputs from options that allow multiple arguments. Options: -a, --accept A List of accepted status codes for valid links The following accept range syntax is supported: `[start]..[[=]end]|code`. Some valid examples are: - 200 (accepts the 200 status code only) - ..204 (accepts any status code < 204) - ..=204 (accepts any status code <= 204) - 200..=204 (accepts any status code from 200 to 204 inclusive) - 200..205 (accepts any status code from 200 to 205 excluding 205, same as 200..=204) Use `lychee --accept '200..=204, 429, 500' ...` to provide a comma- separated list of accepted status codes. This example will accept 200, 201, 202, 203, 204, 429, and 500 as valid status codes. [default: 100..=103,200..=299] --accept-timeouts[=] Accept timed out requests and return exit code 0 when encountering timeouts but not any other errors --archive Web archive to use to provide suggestions for `--suggest`. [default: wayback] [possible values: wayback] -b, --base-url Base URL to use when resolving relative URLs in local files. If specified, relative links in local files are interpreted as being relative to the given base URL. For example, given a base URL of `https://example.com/dir/page`, the link `a` would resolve to `https://example.com/dir/a` and the link `/b` would resolve to `https://example.com/b`. This behavior is not affected by the filesystem path of the file containing these links. Note that relative URLs without a leading slash become siblings of the base URL. If, instead, the base URL ended in a slash, the link would become a child of the base URL. For example, a base URL of `https://example.com/dir/page/` and a link of `a` would resolve to `https://example.com/dir/page/a`. Basically, the base URL option resolves links as if the local files were hosted at the given base URL address. The provided base URL value must either be a URL (with scheme) or an absolute path. Note that certain URL schemes cannot be used as a base, e.g., `data` and `mailto`. --basic-auth Basic authentication support. E.g. `http://example.com username:password` -c, --config Configuration file to use. Can be specified multiple times. If given multiple times, the configs are merged and later occurrences take precedence over previous occurrences. [default: lychee.toml] --cache[=] Use request cache stored on disk at `.lycheecache` --cache-exclude-status A list of status codes that will be ignored from the cache The following exclude range syntax is supported: `[start]..[[=]end]|code`. Some valid examples are: - 429 (excludes the 429 status code only) - 500.. (excludes any status code >= 500) - ..100 (excludes any status code < 100) - 500..=599 (excludes any status code from 500 to 599 inclusive) - 500..600 (excludes any status code from 500 to 600 excluding 600, same as 500..=599) Use `lychee --cache-exclude-status '429, 500..502' ...` to provide a comma-separated list of excluded status codes. This example will not cache results with a status code of 429, 500 and 501. --cache-location Filesystem path used to store the on-disk request cache [default: .lycheecache] --cookie-jar Read and write cookies using the given file. Cookies will be stored in the cookie jar and sent with requests. New cookies will be stored in the cookie jar and existing cookies will be updated. --default-extension Parse input sources without a recognised file type by using the given file extension. This affects how links are extracted from certain input sources. This is useful for stdin inputs, files without extensions, and files with unknown extensions. Examples: --default-extension md --default-extension html To automatically append file extensions when locating files, see `--fallback-extensions`. --dump[=] Don't perform any link checking. Instead, dump all the links extracted from inputs that would be checked --dump-inputs[=] Don't perform any link extraction and checking. Instead, dump all input sources from which links would be collected -E, --exclude-all-private[=] Exclude all private IPs from checking. Equivalent to `--exclude-private --exclude-link-local --exclude-loopback` --exclude Exclude URLs and mail addresses from checking. The values are treated as regular expressions --exclude-link-local[=] Exclude link-local IP address range from checking --exclude-loopback[=] Exclude loopback IP address range and localhost from checking --exclude-path Exclude paths from getting checked. The values are treated as regular expressions --exclude-private[=] Exclude private IP address ranges from checking --extensions A list of file extensions. Files not matching the specified extensions are skipped. Multiple extensions can be separated by commas. Note that if you want to check filetypes, which have multiple extensions, e.g. HTML files with both .html and .htm extensions, you need to specify both extensions explicitly. An example is: `--extensions html,htm,php,asp,aspx,jsp,cgi`. This is useful when the default extensions are not enough and you don't want to provide a long list of inputs (e.g. file1.html, file2.md, etc.) [default: md,markdown,mdx,qmd,rmd,mkd,mkdn,mdwn,mdown,mkdown,html,htm,css,txt,xml] -f, --format Output format of final status report [default: compact] [possible values: compact, detailed, json, junit, markdown] --fallback-extensions When checking locally, attempts to locate missing files by trying the given fallback extensions. Multiple extensions can be separated by commas. Extensions will be checked in order of appearance. The path itself is tried first, then every extension appended to the full file name, then every extension replacing an existing one. So `a.b` with `html,htm` is looked up as `a.b`, `a.b.html`, `a.b.htm`, `a.html`, `a.htm`. An existing extension containing ASCII whitespace is never replaced, since replacing it could discard part of the file name. Example: --fallback-extensions html,htm,php,asp,aspx,jsp,cgi Note: This option takes effect on `file://` URIs which do not exist and on `file://` URIs pointing to directories which resolve to themself (by the --index-files logic). --files-from Read input filenames from the given file or stdin (if path is '-'). This is useful when you have a large number of inputs that would be cumbersome to specify on the command line directly. Examples: ```text lychee --files-from list.txt find . -name '*.md' | lychee --files-from - echo 'README.md' | lychee --files-from - ``` File Format: - Each line should contain one input (file path, URL, or glob pattern). - Lines starting with '#' are treated as comments and ignored. - Empty lines are also ignored. --generate Generate special output (e.g. the man page) instead of performing link checking [possible values: man, config-schema, complete-bash, complete-elvish, complete-fish, complete-powershell, complete-zsh] --github-token GitHub API token to use when checking github.com links, to avoid rate limiting [env: GITHUB_TOKEN] --glob-ignore-case[=] Ignore case when expanding filesystem path glob inputs -h, --help Print help (see a summary with '-h') -H, --header Set custom header for requests. Some websites require custom headers to be passed in order to return valid responses. You can specify custom headers in the format 'Name: Value'. For example, 'Accept: text/html'. This is the same format that other tools like curl or wget use. Multiple headers can be specified by using the flag multiple times. The specified headers are used for ALL requests. Use the `hosts` option to configure headers on a per-host basis. --hidden[=] Do not skip hidden directories and files --host-concurrency Default maximum concurrent requests per host (default: 10) This limits the maximum amount of requests that are sent simultaneously to the same host. This helps to prevent overwhelming servers and running into rate-limits. Use the `hosts` option to configure this on a per-host basis. Examples: --host-concurrency 2 # Conservative for slow APIs --host-concurrency 20 # Aggressive for fast APIs --host-request-interval Minimum interval between requests to the same host (default: 50ms) Sets a baseline delay between consecutive requests to prevent overloading servers. The adaptive algorithm may increase this based on server responses (rate limits, errors). Use the `hosts` option to configure this on a per-host basis. Examples: --host-request-interval 50ms # Fast for robust APIs --host-request-interval 1s # Conservative for rate-limited APIs --host-stats[=] Show per-host statistics at the end of the run -i, --insecure[=] Proceed for server connections considered insecure (invalid TLS) --include URLs to check (supports regex). Has preference over all excludes --include-fragments[=] Enable the checking of fragments in links. Use `none` to disable fragment checks, `anchor-only` for anchor fragments like `#section`, `text-only` for text fragments like `#:~:text=example`, or `full` to check both. If provided without a value, defaults to `anchor-only`. Fragment checking does not work for every URL. In general, the target content needs to be Markdown or HTML and follow common conventions. Anchors that only appear after JavaScript execution may be missed, since lychee does not run a browser engine. --include-mail[=] Also check email addresses --include-verbatim[=] Find links in verbatim sections like `pre`- and `code` blocks --include-wikilinks[=] Check WikiLinks in Markdown files, this requires specifying --base-url --index-files When checking locally, resolves directory links to a separate index file. The argument is a comma-separated list of index file names to search for. Index names are relative to the link's directory and attempted in the order given. If `--index-files` is specified, then at least one index file must exist in order for a directory link to be considered valid. Additionally, the special name `.` can be used in the list to refer to the directory itself. If unspecified (the default behavior), index files are disabled and directory links are considered valid as long as the directory exists on disk. Example 1: `--index-files index.html,readme.md` looks for index.html or readme.md and requires that at least one exists. Example 2: `--index-files index.html,.` will use index.html if it exists, but still accept the directory link regardless. Example 3: `--index-files ''` will reject all directory links because there are no valid index files. This will require every link to explicitly name a file. Note: This option only takes effect on `file://` URIs which exist and point to a directory. -m, --max-redirects Maximum number of allowed redirects [default: 10] --max-cache-age Discard all cached requests older than this duration [default: 1d] --max-concurrency Maximum number of concurrent network requests [default: 128] --max-retries Maximum number of retries per request [default: 3] --min-tls Minimum accepted TLS Version [possible values: TLSv1_0, TLSv1_1, TLSv1_2, TLSv1_3] --mode Set the output display mode. Determines how results are presented in the terminal [default: color] [possible values: plain, color, emoji, task] -n, --no-progress[=] Do not show progress bar. This is recommended for non-interactive shells (e.g. for continuous integration) --no-ignore[=] Do not skip files that would otherwise be ignored by '.gitignore', '.ignore', or the global ignore file -o, --output Output file of status report --offline[=] Only check local files and block network requests -p, --preprocess Preprocess input files with the given command. For each file input, this flag causes lychee to execute `COMMAND PATH` and process its standard output instead of the original contents of PATH. This allows you to convert files that would otherwise not be understood by lychee. The preprocessor COMMAND is only run on input files, not on standard input or URLs. To invoke programs with custom arguments or to use multiple preprocessors, use a wrapper program such as a shell script. An example script looks like this: ```bash #!/usr/bin/env bash case "$1" in *.pdf) exec pdftohtml -i -s -stdout "$1" ;; *.odt|*.docx|*.epub|*.ipynb) exec pandoc "$1" --to=html --wrap=none ;; *) # identity function, output input without changes exec cat ;; esac ``` -q, --quiet... Less output per occurrence (e.g. `-q` or `-qq`) -r, --retry-wait-time Minimum wait time in seconds between retries of failed requests [default: 1] --remap Remap URI matching pattern to different URI --require-https[=] When HTTPS is available, treat HTTP links as errors --root-dir Root directory to use when checking absolute links in local files. This option is required if absolute links appear in local files, otherwise those links will be flagged as errors. This must be an absolute path (i.e., one beginning with `/`). If specified, absolute links in local files are resolved by prefixing the given root directory to the requested absolute link. For example, with a root-dir of `/root/dir`, a link to `/page.html` would be resolved to `/root/dir/page.html`. This option can be specified alongside `--base-url`. If both are given, an absolute link is resolved by constructing a URL from three parts: the domain name specified in `--base-url`, followed by the `--root-dir` directory path, followed by the absolute link's own path. -s, --scheme Only test links with the given schemes (e.g. https). Omit to check links with any other scheme. At the moment, we support http, https, file, and mailto. --skip-missing[=] Skip missing input files (default is to error if they don't exist) --suggest[=] Suggest link replacements for broken links, using a web archive. The web archive can be specified with `--archive` -t, --timeout Website timeout in seconds from connect to response finished [default: 20] -T, --threads Number of threads to utilize. Defaults to number of cores available to the system -u, --user-agent User agent [default: lychee/x.y.z] -v, --verbose... Set verbosity level; more output per occurrence (e.g. `-v` or `-vv`) -V, --version Print version -X, --method Request method(s) Accepts a single method or a comma-separated list. When multiple methods are given, lychee tries each one in order and returns the first success. This is useful for servers that reject `HEAD` requests: `--method head,get` falls back to `GET` when `HEAD` fails. Note: checking URL fragments requires the response body, which is only fetched for `GET` requests. When a link succeeds with a non-`GET` method (e.g. `HEAD`), its fragment is not checked. [default: get] ```
### Exit codes 0 Success. The operation was completed successfully as instructed. 1 Missing inputs or any unexpected runtime failures or configuration errors 2 Link check failures. At least one non-excluded link failed the check. 3 Encountered errors in the config file. ### Ignoring and excluding links You can exclude links from getting checked by specifying regex patterns with `--exclude` (e.g. `--exclude example\.(com|org)`) or by putting them into a file called `.lycheeignore`. To exclude files and directories from being scanned use `--exclude-path`. For more detailed explanations, check out our comprehensive [guide on excluding links](https://lychee.cli.rs/recipes/excluding-links/). ### Caching If the `--cache` flag is set, lychee will cache responses in a file called `.lycheecache` in the current directory. If the file exists and the flag is set, then the cache will be loaded on startup. This can greatly speed up future runs. Note that by default lychee will not store any data on disk. This is explained in more detail in [our documentation](https://lychee.cli.rs/recipes/caching/). ### Configuration file schema The generated [JSON schema](https://github.com/lycheeverse/lychee/blob/HEAD/docs/schema.json) provides configuration key completion, hover documentation, and validation in compatible TOML editors such as [Taplo](https://taplo.tamasfe.dev/). Generate a schema matching your installed version of lychee: ```sh lychee --generate config-schema > lychee.schema.json ``` Then add this directive at the top of `lychee.toml`. The path is relative to the config file: ```toml #:schema ./lychee.schema.json ``` Alternatively, reference the development schema directly: ```toml #:schema https://raw.githubusercontent.com/lycheeverse/lychee/master/docs/schema.json ``` The schema is generated from the Rust configuration types. After changing them, regenerate it from the repository root: ```sh cargo run --locked --bin lychee -- --generate config-schema > docs/schema.json ``` ## Supported file formats lychee supports HTML and Markdown file formats. For any other file format, lychee falls back to a "plain text" mode. This means that [linkify](https://github.com/robinst/linkify) attempts to extract URLs on a best-effort basis. For non-plaintext files (pdf, epub, docx, etc.) or for files which don't work well with the fallback extraction method (csv, ipynb, etc.) you can make use of the `--preprocess` option. Take a look at [lychee-all](https://github.com/lycheeverse/lychee-all) for more information. ## Library usage You can use lychee as a library for your own projects! > The README is long; the above is its first 40000 characters. Full content: https://github.com/lycheeverse/lychee