The Plain Fetch viewer

In short

The viewer requests a URL the way a plain-fetch agent does: no JavaScript, one request for HTML, one for markdown, one for llms.txt and one for a path that should not exist. It shows the initial HTML on the left, the readable text on the right, and seven flags underneath.

Pre-loaded with www.wikipedia.org, read 4 November 2026. Type any public URL to run your own.

GET https://readthedocs.io/ answered 200 with text/html, 33 KB, 3 redirects, read 9 November 2026, 15:06 UTC. Final URL: https://about.readthedocs.com/?ref=app.readthedocs.org.

Permalink: /viewer/?url=https://readthedocs.io/

The page answers a plain fetch: 3 of 6 checks found.

Initial HTML what a plain fetch receives

<!DOCTYPE html>
<html lang="en">

<head>
<title>Full featured documentation deployment platform - Read the Docs</title>
<meta charset="utf-8" />
<meta name="generator" content="Pelican" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
[... 1 more head element folded ...]
<link rel="canonical" href="https://about.readthedocs.com/" />
[... 3 more head elements folded ...]
<meta name="description" content="Read the Docs is a documentation building and hosting platform aimed at helping developers creating documentation from code with versioned documentation, integrated search, pull request previews and more." />
[... 12 more head elements folded ...]
<link href="https://about.readthedocs.com//feeds/atom.xml" type="application/atom+xml" rel="alternate" title="Read the Docs Atom Feed" />
[... 9 more head elements folded ...]
</head>

<body>

<div class="ui basic fitted attached segment">
  <div class="ui container">
    <div class="ui middle aligned grid">

        <div class="four wide computer five wide tablet eleven wide mobile left aligned column">
          <div class="ui horizontally fitted basic segment">
            <a href="https://about.readthedocs.com/" aria-label="Read the Docs homepage">
              <img class="ui image" src="https://about.readthedocs.com/theme/img/logo-wordmark-dark.svg" width="220" alt="Read the Docs logo"/>
            </a>
          </div>
        </div>

        <div class="five wide mobile only right aligned column">
          <div class="ui wide dropdown" data-module="dropdown" data-action="select">
            <i class="fad fa-bars large icon" style="--fa-secondary-opacity: 0.8;"></i>
            <div class="left menu">

              <a class="item" href="https://about.readthedocs.com/features/">
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                Product
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              <a class="item" href="https://about.readthedocs.com/pricing/">
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                Pricing
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              <a class="item" href="https://about.readthedocs.com/blog/">
                <i class="fad fa-newspaper fa-swap-opacity primary icon"></i>
                Blog
              </a>
              <a class="item" href="https://docs.readthedocs.io" target="_blank">
                <i class="fad fa-book primary icon"></i>
                Docs
              </a>

              <div class="divider"></div>

                <div class="header">Log in</div>
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    Read the Docs Community

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      <code>https://readthedocs.org</code>
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    <i class="fad fa-circle-question grey icon"></i>
    Choosing a platform
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        <div class="twelve wide computer eleven wide tablet left aligned tablet only computer only column">
          <div class="ui big borderless secondary menu">

            <a class="item" href="https://about.readthedocs.com/features/">
              Product
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              Pricing
            </a>

            <a class="item" href="https://about.readthedocs.com/blog/">
              Blog
            </a>

            <a class="item" href="https://docs.readthedocs.io" target="_blank">
              Docs
            </a>

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              <div class="item">
                <div class="ui floating top right pointing dropdown" data-module="dropdown" data-action="select" data-display-type="block">
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      <code>https://readthedocs.org</code>
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                  </div>

Shown with 4 long blocks (scripts, styles, long tags) folded into a marker that says how many characters they hide; the pane stops after the first 200 words; the page is 33 KB.

Reading view the text a plain-fetch client can extract

title: Full featured documentation deployment platform - Read the Docs

Your Documentation Infrastructure Layer

Product Pricing Blog Docs Log in Read the Docs Community https://readthedocs.org Read the Docs Business https://readthedocs.com Sign up Choosing a platform Product Pricing Blog Docs Log in Log in Read the Docs Community https://readthedocs.org Read the Docs Business https://readthedocs.com Choosing a platform Sign up Get started with Read the Docs Which site best fits your project? Read the Docs Community For free and open-source projects Clone public repositories Public documentation Ads supported hosting Free for open-source software. Sign up Read the Docs Business For commercial and non-free projects Clone private and public repositories Public and private documentation Team management for your organization Plans starting at $50/month. Sign up Choosing a platform Explore all the features Your Documentation Infrastructure Layer Connect your Git repository and treat docs like code. We run the hard parts: builds, previews, auth -- so you can focus on creating great docs. For engineering and docs teams Your engineering team shouldn't have to run a docs platform team. We run the infrastructure so your writers and developers ship documentation, instead of worrying about pipelines. Start your 30-day free trial For open source projects Always free for open source and community projects. We've hosted open source documentation since

515 more words follow in the initial HTML.

3 found, 2 missing, 2 notes, from 7 checks run

H1Found
200 wordsFound
llms.txtNote
MarkdownFound
Missing pathMissing
JSON-LDMissing
OpenAPINote

What a plain fetch found on readthedocs.io
Check	Result	Detail
H1 in the initial HTML	Found one H1	First H1: Your Documentation Infrastructure Layer
First 200 words in the initial HTML	Found 200 of 200 words	The initial HTML carries 715 words of visible text; the first 200 are marked in the left pane.
llms.txt present and linked	Note present, not linked	7134 bytes, 34 links. Structure grade C (4 of 6). Nothing on the home page points to it. Ora's lab found 86 percent of llms.txt fetches arrived through a link.
Markdown on request	Found text/markdown	Accept: text/markdown returned 200 with text/markdown; charset=utf-8. Vary: Accept is set.
Status of a made-up path	Missing 200 (soft 404)	/agent-ready-html-missing-path-check returned 200. A missing page that answers 200 looks like a live page to an agent.
JSON-LD types	Missing none	No JSON-LD block on the home page. Ora's lab found it made no difference when the answer was already in the HTML; Google says it is not needed for AI features.
OpenAPI link	Note none on the home page	No OpenAPI link on the home page. It matters only for a site that ships an API.

Run the full check

The viewer read one page with four requests. The full check we recommend next is Ora's scan. Its Access layer runs 42 checks worth 30 of its 100 points, among them content without JavaScript, bot detection, llms.txt, markdown on request, JSON-LD and the sitemap (Ora's check catalogue, contract 1.38.0, read 5 November 2026). Open Ora's report for readthedocs.io.

Limits: Ora reads public URLs only, says two runs of one scan land within a couple of points without publishing repeat-scan data, and keeps the product that fixes what it finds behind a waitlist. Cloudflare's scanner at isitagentready.com is a quick free alternative, and Mintlify's score covers documentation.

What the viewer does

It sends four plain GET requests with the user agent Mozilla/5.0 (compatible; agent-readiness-crawl/1.0): the URL itself, the same URL with Accept: text/markdown, /llms.txt on the same host, and a made-up path at the root. It runs no JavaScript. The left pane is the first bytes of the HTML as text, with long scripts and styles folded into a marker that says how many characters they hide. The H1 and the first 200 words of visible text are marked in both panes. The flags under the panes say what the four responses added up to.

Limits

Ten seconds for all four requests together, 1.5 MB read from the home page, at most five redirects, each one checked again.
http and https only, default ports only. Private, local and internal addresses and names are refused.
Ten runs per address per minute. The counter lives in memory on the edge function, so it is per instance rather than global. Past ten you get a 429 with a Retry-After header.
Results are cached for 24 hours by the response headers. Nothing is written to a database: the viewer keeps the first 200 words and the extracted fields for the length of the request and keeps no page body beyond that.

What it does not tell you

A plain fetch from this server is not a real agent. Bot protection weighs the source address more than the user agent, so a page that answers 200 here can still refuse an agent, and the reverse. Ora's lab found (2026-10-19) that returning 403 to agent user agents and hiding the answer in JavaScript were the only two of 19 configurations that stopped retrieval; the viewer can see the second, and can only hint at the first. The initial HTML reference covers both. The server logs and the published crawler address ranges settle the first.

The seven flags

H1 in the initial HTML: Whether the HTML the server sends already contains an H1. It is the cheapest sign that the page does not depend on scripts to say what it is.
First 200 words in the initial HTML: Whether at least 200 words of visible text arrive in the initial HTML. Under 40 words with an app root element is flagged as a JavaScript shell.
llms.txt present and linked: Whether /llms.txt answers with a plain-text file, whether the home page links it (an anchor, a link element or a Link header), and the structure grade the index uses.
Markdown on request: Whether a request with Accept: text/markdown comes back as text/markdown. Cloudflare Radar found 3.9 percent of scanned top sites passing this at its April 2026 launch.
Status of a made-up path: Whether a path that should not exist returns 404 or 410. A 200 is a soft 404 and reads as a live page.
JSON-LD types: The schema.org types found in JSON-LD blocks on the page. Ora's lab found JSON-LD made no difference when the answer was already in the HTML.
OpenAPI link: Whether the page links an OpenAPI file, by an anchor or a service-desc link relation. It matters only for a site that ships an API.

Sources

Ora: AgentReady launch post (Ora's lab findings) https://ora.ai/blog/agentready-launch, read 4 November 2026
Ora check catalogue, contract 1.38.0 (132 checks, 42 in the Access layer) https://ora.ai/api/checks, read 5 November 2026
Ora home page (the fixing product is behind a waitlist) https://ora.ai/, read 5 November 2026
Ora: Introducing Deep Scan (repeat scans) https://ora.ai/blog/introducing-deep-scan, read 5 November 2026
Ora llms.txt (public URLs only) https://ora.ai/llms.txt, read 5 November 2026
Vercel: Make your site readable by AI agents https://vercel.com/kb/guide/make-your-site-readable-by-ai-agents, read 4 November 2026
llms.txt proposal (llmstxt.org) https://llmstxt.org/, read 4 November 2026

Last reviewed 5 November 2026