web2cli

Every website is a Unix command.

Browse Hacker News, search X.com, write Discord messages, read Reddit — all from your terminal. No browser, no API keys, no $100/mo plans.

$ web2cli hn top --limit 3
┌──────┬──────────────────────────────────────────┬───────┬──────────┐
│ RANK │ TITLE                                    │ SCORE │ COMMENTS │
├──────┼──────────────────────────────────────────┼───────┼──────────┤
│ 1    │ Show HN: I built a CLI for every website │ 313   │ 37       │
│ 2    │ Why agents don't need browsers           │ 271   │ 89       │
│ 3    │ The Unix philosophy, 50 years later      │ 198   │ 64       │
└──────┴──────────────────────────────────────────┴───────┴──────────┘

$ web2cli login x --browser
$ web2cli x search --query "build for agents" --limit 1 --format json
[
  {
    "author": "@karpathy",
    "text": "CLIs are super exciting precisely because they are a \"legacy\" technology, which means AI agents can natively and easily use them, combine them, interact with them via the entire terminal toolkit.\n\nE.g ask your Claude/Codex agent to install this new Polymarket CLI and ask for any https://t.co/gzrpg0erGz",
    "date": "2026-02-24 18:17",
    "retweets": 1085,
    "likes": 11481,
    "replies": 610,
    "views": "1923316"
  }
]

$ web2cli login discord --browser
$ web2cli discord send --server "My Server" --channel general --message "deployed 🚀" > /dev/null

Why?

• For agents: HTTP GET, not Chromium. 50ms not 5s. $0.000001 not $0.10.
• For humans: curl for the modern web. Pipe, grep, script anything.
• For both: One interface. web2cli <site> <command>. That's it.

pip install web2cli

Performance

web2cli makes direct HTTP requests. No browser, no DOM, no screenshots.

Metric	Browser automation	web2cli
Fetch 10 top news from HN	~20s (launch + render)	0.5s
Memory per request	~821.3MB (Chromium)	~5MB (HTTP)
Cost at 10k req/day	$20/day (just LLM) ~$23.3/day (LLM + remote browser)	~$0 (HTTP)
Tokens to parse	~8647 (HTML/DOM estimate)	~300 (Markdown table)

Real-world benchmarks

Task	Official API	Browser	web2cli	Speedup
Read Discord messages	✓ has API	26s	0.63s	41x
Send a Slack message	✓ has API	35s	0.60s	58x
Search X	$100/mo API	75s	1.54s	50x
Search Stack Overflow	300 req/day	41s	0.65s	63x
Fetch HN submissions	partial API	36s	1.42s	25x

Some sites have great APIs. Some have expensive ones. Some have none. web2cli gives you one interface for all of them

What this means for agents

Scenario	Browser automation	web2cli
Monitor Discord (1 check/min)	$2.88/day	$0.0015/day
Scan X every 5 min, 24/7	$1.58/day	$0.0003/day
10k daily actions (typical bot)	~$50/day	~$0.01/day
Monthly infra for active agent	$50+/mo	$4/mo

Browser automation is the right choice for sites that require JS rendering or complex interaction flows. web2cli is for the 80% of tasks that don't.

More code examples

Daily HN top stories summary

web2cli hn top --limit 3 --fields title,url --format md | \
claude -p "For each story, fetch the URL and write a 1-sentence summary. Output as a bullet list." --allowedTools "WebFetch" | \
web2cli discord send --server "ZENO.blue" --channel "testy-mo" > /dev/null

Minimal Discord answering bot

import json, subprocess, time, anthropic

NICK = "your_nickname"
SERVER = "YOUR_SERVER_NAME"
CHANNEL = "channel_name_here"
SYSTEM = "You are a bot on Discord. Respond briefly, in user language, without markdown."

seen = set()


def web2cli(*args):
    result = subprocess.run(["web2cli", "discord", *args, "--format", "json"], capture_output=True, text=True)
    return json.loads(result.stdout or "[]")


def fetch():
    return web2cli("messages", "--server", SERVER, "--channel", CHANNEL, "--limit", "20")


def send(text):
    web2cli("send", "--server", SERVER, "--channel", CHANNEL, "--message", text)


def fmt(msgs):
    return "\n".join(f'{m["author"]}: {m["content"]}' for m in msgs)


def ask(context, new_msgs):
    resp = anthropic.Anthropic().messages.create(
        model="claude-sonnet-4-6", max_tokens=512, system=SYSTEM,
        messages=[{"role": "user", "content": f"Last messages:\n{context}\n\nNew for you:\n{new_msgs}"}],
    )
    return resp.content[0].text


# Seed seen IDs
for m in fetch():
    seen.add(m["id"])

print(f"Watching #{CHANNEL} for @{NICK}...")

while True:
    time.sleep(30)
    msgs = fetch()
    new = [m for m in msgs if m["id"] not in seen and NICK in m.get("content", "").lower()]
    for m in msgs:
        seen.add(m["id"])
    if not new:
        continue
    reply = ask(fmt(msgs), fmt(new))
    print(f"→ {reply}")
    send(reply)

Built-in Adapters

Current built-in adapters and actions:

discord.com (dc, discord)

• me - Show current user info
• servers - List your Discord servers (guilds)
• channels - List channels in a server
• messages - Get messages from a channel
• send - Send a message to a channel
• dm - List DM conversations
• dm-messages - Get messages from a DM conversation
• dm-send - Send a DM to a user

news.ycombinator.com (hn)

• top - Get top stories from Hacker News
• new - Get newest stories
• item - Get a single HN item (story, comment, job)
• search - Search HN stories (via Algolia)
• saved - Get saved stories (requires login)
• upvoted - Get upvoted stories (requires login)
• submissions - Get a user's submissions

reddit.com (reddit)

• posts - List posts from a subreddit
• thread - Get a thread with comments
• search - Search posts in a subreddit

slack.com (slack)

• me - Show current user and workspace info
• channels - List channels in workspace
• messages - Get messages from a channel
• send - Send a message to a channel
• dm - List DM conversations
• dm-messages - Get messages from a DM conversation
• dm-send - Send a DM to a user

stackoverflow.com (so)

• search - Search Stack Overflow questions
• question - Read a specific question and its top answers
• tagged - Browse questions by tag

x.com (x, twitter)

• tweet - Get a single tweet by ID or URL
• profile - Get user profile info
• search - Search tweets
• timeline - Home timeline (For you tab)
• following - Following timeline

To inspect adapter details from CLI:

web2cli adapters list
web2cli adapters info <domain-or-alias>

Documentation

Key docs for contributors:

• docs/adapter-spec.md - canonical adapter specification (current: 0.2)
• docs/llm-adapter-playbook.md - adapter authoring workflow for LLM agents
• docs/adapter-spec.schema.json - machine-readable schema for quick structural checks

Custom Adapters Quickstart

Create a minimal custom adapter end-to-end using httpbin.org (global, simple, auth-friendly test target).

1. Create adapter directory:

mkdir -p ~/.web2cli/adapters/httpbin.org

2. Create ~/.web2cli/adapters/httpbin.org/web2cli.yaml:

meta:
  spec_version: "0.2"
  name: httpbin
  domain: httpbin.org
  base_url: https://httpbin.org
  version: 0.2.0
  description: "HTTPBin demo adapter"
  author: custom
  aliases: [hb]
  transport: http
  impersonate: chrome
  default_headers:
    Accept: "application/json"

auth:
  methods:
    - type: token
      env_var: WEB2CLI_HTTPBIN_TOKEN
      inject:
        target: header
        key: Authorization
        prefix: "Bearer "
    - type: cookies
      keys: [session]
      env_var: WEB2CLI_HTTPBIN_COOKIES

commands:
  ip:
    description: "Show IP seen by server"
    pipeline:
      - request:
          name: fetch
          method: GET
          url: /ip
      - parse:
          name: parsed
          from: fetch
          format: json
          extract: "$"
          fields:
            - name: origin
              from: "$.origin"
    output:
      from_step: parsed
      default_fields: [origin]
      default_format: table

  bearer-check:
    description: "Check bearer auth"
    pipeline:
      - request:
          name: fetch
          method: GET
          url: /bearer
      - parse:
          name: parsed
          from: fetch
          format: json
          extract: "$"
          fields:
            - name: authenticated
              from: "$.authenticated"
              default: false
            - name: token
              from: "$.token"
              default: ""
    output:
      from_step: parsed
      default_fields: [authenticated, token]
      default_format: table

  cookies:
    description: "Echo cookies seen by server"
    pipeline:
      - request:
          name: fetch
          method: GET
          url: /cookies
      - parse:
          name: parsed
          from: fetch
          format: json
          extract: "$.cookies"
    output:
      from_step: parsed
      default_format: json

3. Validate and lint:

web2cli adapters validate
web2cli adapters lint httpbin.org

4. Inspect and run:

web2cli adapters info hb
web2cli hb ip

5. Test token auth (session-based):

web2cli login hb --token "abc123"
web2cli hb bearer-check --trace --verbose

6. Test cookie auth:

web2cli login hb --cookies "session=my-session"
web2cli hb cookies --format json

If you prefer env vars instead of stored sessions:

export WEB2CLI_HTTPBIN_TOKEN="abc123"
export WEB2CLI_HTTPBIN_COOKIES="session=my-session"
web2cli hb bearer-check
web2cli hb cookies

Debugging and Quality

# Validate + semantic lint all adapters
web2cli adapters validate
web2cli adapters lint

# Inspect step-by-step runtime trace for a command
web2cli reddit posts --sub python --limit 3 --trace

# Disable adapter/parser truncation (full text fields)
web2cli so question --id 79861629 --format json --no-truncate

# Diagnose browser stack used by `login --browser`
web2cli doctor browser
web2cli doctor browser --deep

Browser Login

For sites that use cookies and/or runtime tokens, you can capture a session directly from a real browser:

web2cli login x.com --browser

web2cli opens Chromium and waits until all required auth values are available:

• required cookie keys from auth.methods[].keys
• token values defined by auth.methods[].capture (for type: token)

Then it encrypts and stores the session in ~/.web2cli/sessions/<domain>.json.enc.

Token capture example in adapter YAML:

auth:
  methods:
    - type: token
      env_var: WEB2CLI_DISCORD_TOKEN
      inject:
        target: header
        key: Authorization
      capture:
        from: request.header
        key: Authorization
        match:
          host: discord.com
          path_regex: "^/api/"

Inspect current login state:

web2cli login x.com --status

Troubleshoot browser capture flow:

web2cli login slack --browser --browser-debug

This prints live capture state (have/missing cookies, token status, tracked tabs in browser context).

--browser automatically picks the best browser strategy (including local Chrome fallback for stricter sites) so users typically don't need extra setup.

For LLMs

If you are using an LLM/agent to generate a new adapter, use this flow:

1. Start from docs/llm-adapter-playbook.md and the minimal adapter template.
2. Prefer declarative steps (resolve, request, fanout, parse, transform).
3. Avoid custom parser scripts unless declarative parsing is truly insufficient.
4. Always run web2cli adapters validate, web2cli adapters lint, and at least one command with --trace.
5. Do not stop until all three checks pass and output fields look correct.

web2cli Cloud (coming soon)

Building an agent for other people? Cloud handles auth so you don't have to.

Your users click a link, log in to any site in a sandboxed browser, and your agent gets an opaque session token. No cookies touch your server.

Think "OAuth for websites that don't have OAuth."

→ Join the waitlist

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Created by @michaloblak.