zlib

A CLI for Z-Library.

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Features

🔍 Interactive search — browse results with ↑/↓, switch pages with ←/→
📥 Book download — by book ID, from search results, with live progress
📚 Download history — paginated history browser with download support
📖 Send to Kindle — deliver files to your Kindle address
🕒 Usage profile — view daily download quota
🎨 Themes — auto, mocha, latte, dracula, tokyo, nord, gruvbox
🌐 Proxy & custom domain support for restricted networks

Install

Homebrew (macOS / Linux):

brew install heartleo/tap/zlib

winget (Windows):

winget install heartleo.zlib

curl (macOS / Linux):

curl -fsSL https://raw.githubusercontent.com/heartleo/zlib/main/install.sh | sh

Go install (requires Go 1.25+):

go install github.com/heartleo/zlib/cmd/zlib@latest

Build from source:

git clone https://github.com/heartleo/zlib
cd zlib
go build -o zlib ./cmd/zlib

Claude Code plugin

zlib ships a Claude Code plugin, so Claude can search and download books for you.

/plugin marketplace add heartleo/zlib
/plugin install zlib@zlib-plugin-cc

/zlib "the pragmatic programmer" to search and download. /zlib:kindle sends a book to your Kindle.

Codex plugin

zlib also ships a skills-only plugin for Codex:

codex plugin marketplace add heartleo/zlib
codex plugin add zlib@zlib

Ask Codex to search or download a book with zlib. Use the bundled Kindle skill when you want to send a local book file to your Kindle.

Quick Start

Set ZLIB_DOMAIN first. Z-Library mirrors change often and most of them are behind DiamWall, so there is no default that stays correct. Every command resolves its mirror from ZLIB_DOMAIN before anything else, and a wrong or stale value is the single most common cause of a login that succeeds and a next command that fails.

Most current Z-Library web domains put automated requests behind DiamWall, so the recommended setup uses EAPI. Probe the candidates first, then set ZLIB_DOMAIN to one reported as healthy or challenged:

zlib doctor --eapi
export ZLIB_DOMAIN=https://z-lib.gd     # pick one doctor reported usable
zlib login --eapi
zlib search "dune"

A successful login records that domain as ZLIB_DOMAIN in ~/.config/zlib/.env, so the setting survives a new shell and you do not have to remember it. Other keys in that file are left untouched. Two things still outrank it, and a stale value in either shadows what the login wrote: a real environment variable, and a .env in the working directory.

challenged means the domain answered with Z-Library's own JS proof-of-work page. That domain is usable: the client solves the challenge automatically, so pick it as readily as a healthy one. Only diamwall_blocked, http_error, redirect_loop and network_error are unusable.

EAPI login checks the selected domain again before asking for account credentials. If no candidate is usable, see Troubleshooting DiamWall.

Commands

login

zlib login
zlib login --email [email protected] --password secret
zlib login --cookies ~/Downloads/cookies.txt --domain https://z-lib.gd
zlib login --eapi --domain https://z-lib.gd
# or set ZLIB_DOMAIN=https://z-lib.gd, then:
zlib login --eapi

Saves session to ~/.config/zlib/session.json, and records the domain it used as ZLIB_DOMAIN in ~/.config/zlib/.env so later commands reach the same mirror without you setting anything. The interactive login remembers and prefills the last successful email address, but never stores the password. --cookies imports a user-supplied Netscape/Mozilla-format cookie file; only unexpired root cookies matching --domain are saved to the session. Cookie files contain reusable credentials, so keep the exported file private.

If you omit --domain, both HTML and EAPI login read ZLIB_DOMAIN. When neither is set, the command prints the required setting and exits. EAPI login also checks the selected domain before asking for account credentials. If the check fails, it tells you to choose another domain. Cookie imports follow the same rule.

--eapi selects the unofficial mobile app API and saves that choice in the session. Search, profile, history, book details, downloads, and Kindle delivery then use the EAPI path where needed. Book references use id:hash, for example zlib download 115066162:e9f13b --send-to-kindle. See EAPI mode for the endpoint list and stability notes.

If /eapi/user/login refuses to issue credentials, --eapi login falls back to the HTML login form and continues in EAPI mode. The EAPI authenticates on nothing but remix_userid/remix_userkey, and the HTML form hands out the same pair, so the fallback session is not degraded. See EAPI login says Authorization failed.

logout

zlib logout

search

Without arguments, opens an interactive picker:

type a query and confirm
browse results with ↑/↓
switch pages with ←/→
press Enter to download

zlib search # interactive mode
zlib search "dune" --page 2 # static table
zlib search "dune" --json   # machine-readable output for scripts and plugins

Filter by file format with --ext (or its alias --format), repeatable.

zlib search "python crash course" --ext epub --ext pdf

Use --full-title to disable title truncation

zlib search "civilized to death" --full-title

download

zlib download Gz31nyAV5E
zlib download Gz31nyAV5E --dir ./books --send-to-kindle
zlib download Gz31nyAV5E --dir "~/Downloads"

--dir expands a leading ~ itself, so it works whether or not the shell expanded it.

To stop repeating the same folder, set ZLIB_DOWNLOAD_DIR once and drop the flag. download, search and history all fall back to it, and an explicit --dir still wins for that one run:

echo 'ZLIB_DOWNLOAD_DIR=~/Downloads' >> ~/.config/zlib/.env
zlib download Gz31nyAV5E              # saves to ~/Downloads
zlib download Gz31nyAV5E --dir .      # this one lands here instead

Neither the flag nor the variable creates the directory — make it first if it does not exist.

Press Ctrl+C to cancel. Incomplete files are removed automatically.

history

Without flags, opens an interactive history browser:

browse with ↑/↓, switch pages with ←/→
press Enter to re-download

zlib history
zlib history --download Gz31nyAV5E --dir ./books
zlib history --format epub
zlib history --json   # machine-readable, always non-interactive

profile

zlib profile
zlib profile --json

doctor

Checks all known domains without logging in or changing the active domain. --proxy overrides ZLIB_PROXY for this check only.

zlib doctor
zlib doctor --eapi
zlib doctor --proxy http://127.0.0.1:7890
zlib doctor --proxy socks5://127.0.0.1:9050 --json

--eapi checks /eapi/info/domains instead of the home page. A domain may block the website while leaving EAPI reachable, so the two checks can disagree.

Troubleshooting DiamWall (issue #16)

In issue #16, the mirror serves a DiamWall challenge where the CLI expects Z-Library HTML or JSON. You may see an HTTP 307 redirect loop, HTTP 517, or Access Denied | DiamWall. Older CLI versions may instead fail with searchResultBox not found, dstats-info not found, or invalid character '<' while decoding login JSON.

Check both website and EAPI connectivity:

zlib doctor --json
zlib doctor --eapi --json

Set ZLIB_DOMAIN to a domain reported as healthy or challenged, then log in with EAPI:
```
export ZLIB_DOMAIN=https://z-lib.gd
zlib login --eapi
zlib search "golang"
```
If your network requires a proxy, run the check through that proxy before setting it for other commands:
```
zlib doctor --eapi --proxy http://127.0.0.1:7890
export ZLIB_PROXY=http://127.0.0.1:7890
```

challenged means the domain served Z-Library's own JS proof-of-work page; the client clears it automatically, so the domain is usable. diamwall_blocked means DiamWall intercepted the request. redirect_loop means the redirects never reached content. http_error covers responses such as 403; network_error covers DNS, TLS, timeout, reset, and EOF failures. Changing the User-Agent or importing login cookies does not solve a DiamWall JS/TLS challenge. Use a healthy or challenged EAPI domain, or a different network route.

EAPI login says `Authorization failed`

Error: login failed: zlibrary: login failed: Authorization failed

Z-Library gates /eapi/user/login separately from the rest of the EAPI. An account it refuses this way still drives /eapi/user/profile, /eapi/book/search and /eapi/user/book/downloaded normally. The message is also not a wrong password: a wrong one comes back Incorrect email or password instead.

The CLI handles this on its own by logging in through the HTML form and continuing in EAPI mode, so on a current build the login simply succeeds. If you see the message, you are on a build older than that fallback — upgrade, or import a browser cookie file instead:

zlib login --cookies ~/Downloads/cookies.txt --domain https://z-lib.gd

Incorrect email or password really is a credential failure. Note that a password containing shell metacharacters can be mangled by --password; omit the flag and let the prompt take it.

Commands fail after a successful login

Error: zlibrary: blocked by anti-bot protection (HTTP 517) at https://z-lib.sk/...
Error: zlibrary: unexpected HTTP status 503 at https://z-lib.gd/users/downloads

A ZLIB_DOMAIN left over from an earlier setup overrides the domain the login just saved, so zlib login --domain https://z-lib.gd can succeed and the very next command still target the old mirror. Check the effective value before suspecting anything else — .env files in the working directory and in ~/.config/zlib/ both feed it:

echo "$ZLIB_DOMAIN"
grep -r ZLIB_DOMAIN .env ~/.config/zlib/.env 2>/dev/null

Point it at a domain zlib doctor --eapi reports as healthy or challenged, or remove it entirely to fall back to the domain saved in the session.

A bare 503 from a healthy or challenged domain means the build predates the challenge fix and is treating Z-Library's own proof-of-work page as an error. Upgrade.

Recommended access domains

Measured 2026-09-04 by probing /eapi/user/login on each host. The list is maintained from measurement rather than from Z-Library's own /eapi/info/domains, which advertises hosts that are DiamWall-fronted and omits several that work.

Allowed domain	EAPI (measured 2026-09-04)
`z-lib.gd`	works (EAPI default)
`z-lib.gl`	works
`z-library.ec`	works (EAPI only; the HTML site is Cloudflare-blocked)
`zlib.bz`	works
`article.sk`	works
`articles.sk`	works
`zliba.ru`	redirects to `zlib.bz`; `login --eapi` follows it
`1lib.sk`	DiamWall-blocked
`z-lib.fm`	DiamWall-blocked
`z-lib.sk`	DiamWall-blocked

z-library.gs was removed: its TLS handshake fails. Run zlib doctor --eapi for the current picture rather than trusting this table, which ages.

kindle

Configure Kindle delivery settings:

recipient Kindle address
sender address
SMTP host and port

SMTP password is never stored on disk — set ZLIB_SMTP_PWD instead.

zlib kindle                  # configure
zlib kindle send             # pick a file interactively
zlib kindle send ./dune.epub # send a local file

Supported formats: EPUB PDF MOBI TXT DOC DOCX RTF HTML

theme

zlib theme           # show current
zlib theme auto      # follow terminal background
zlib theme nord      # set globally

Available: auto · mocha · latte · dracula · tokyo · nord · gruvbox

Configuration

Keep secrets like ZLIB_SMTP_PWD out of your shell history — put them in an .env file instead of exporting them inline. zlib reads env vars with this precedence: real environment > working-directory .env > ~/.config/zlib/.env. The global file is the recommended home for machine-wide values.

HTML and EAPI both read ZLIB_DOMAIN. It overrides the domain saved in ~/.config/zlib/session.json; if you unset it, the CLI uses the saved domain. A new login without --domain requires ZLIB_DOMAIN. EAPI login checks that domain before requesting account credentials.

A successful login writes ZLIB_DOMAIN into ~/.config/zlib/.env, replacing the assignment already there and leaving every other line alone. That is the lowest-precedence of the three sources, so an exported variable or a working-directory .env still wins over it — check those first when a command targets a mirror you did not choose.

Variable	Description
`ZLIB_DOMAIN`	Domain for HTML and EAPI; used when login omits `--domain`
`ZLIB_PROXY`	Proxy URL, e.g. `http://127.0.0.1:7890`
`ZLIB_SMTP_PWD`	SMTP password for Kindle delivery
`ZLIB_THEME`	Override theme without changing config
`ZLIB_DOWNLOAD_DIR`	Default destination for downloads when `--dir` is omitted
`ZLIB_DOWNLOAD_RETRIES`	Retries for dropped connections and `502`/`503`/`504` responses

ZLIB_DOWNLOAD_RETRIES defaults to 3.

ZLIB_DOWNLOAD_DIR applies to download, search and history, and expands a leading ~. An explicit --dir always overrides it, so --dir . still means the current directory. Unset or blank, downloads land in the current directory as before.

Edit the global env file (~/.config/zlib/.env, one KEY=value per line):

mkdir -p ~/.config/zlib && touch ~/.config/zlib/.env && chmod 600 ~/.config/zlib/.env
# open it in your editor:
notepad "$env:USERPROFILE\.config\zlib\.env"   # Windows (PowerShell)
open -t ~/.config/zlib/.env                       # macOS
${EDITOR:-nano} ~/.config/zlib/.env               # Linux

Name		Name	Last commit message	Last commit date
.agents/plugins		.agents/plugins
.claude-plugin		.claude-plugin
.github/workflows		.github/workflows
cmd/zlib		cmd/zlib
docs		docs
internal		internal
plugins/zlib		plugins/zlib
scripts		scripts
site		site
.env.example		.env.example
.gitignore		.gitignore
.goreleaser.yml		.goreleaser.yml
LICENSE		LICENSE
Makefile		Makefile
README.md		README.md
README.zh.md		README.zh.md
book.go		book.go
book_test.go		book_test.go
challenge.go		challenge.go
client.go		client.go
client_test.go		client_test.go
constants.go		constants.go
constants_test.go		constants_test.go
domain_policy.go		domain_policy.go
domain_policy_test.go		domain_policy_test.go
domain_probe.go		domain_probe.go
domain_probe_test.go		domain_probe_test.go
download.go		download.go
download_test.go		download_test.go
eapi.go		eapi.go
eapi_book.go		eapi_book.go
eapi_book_test.go		eapi_book_test.go
eapi_profile.go		eapi_profile.go
eapi_profile_test.go		eapi_profile_test.go
eapi_test.go		eapi_test.go
errors.go		errors.go
go.mod		go.mod
go.sum		go.sum
install.sh		install.sh
kindle.go		kindle.go
kindle_test.go		kindle_test.go
model.go		model.go
parser.go		parser.go
parser_test.go		parser_test.go
profile.go		profile.go
search.go		search.go
urls.go		urls.go
version.go		version.go

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zlib

Features

Install

Claude Code plugin

Codex plugin

Quick Start

Commands

login

logout

search

download

history

profile

doctor

Troubleshooting DiamWall (issue #16)

EAPI login says `Authorization failed`

Commands fail after a successful login

Recommended access domains

kindle

theme

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zlib

Features

Install

Claude Code plugin

Codex plugin

Quick Start

Commands

login

logout

search

download

history

profile

doctor

Troubleshooting DiamWall (issue #16)

EAPI login says Authorization failed

Commands fail after a successful login

Recommended access domains

kindle

theme

Configuration

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EAPI login says `Authorization failed`