Tool Overview

The Markdown TOC Generator builds a table of contents for your Markdown documents automatically. You paste or type Markdown into the editor, and the tool scans your headings, builds a nested list of links, and outputs either Markdown list syntax or HTML list code depending on your settings. It supports different anchor presets so that generated links work with common Markdown viewers.

This solves a real problem for writers and developers. Long Markdown files are hard to navigate without a table of contents. Manually creating a TOC is tedious and easy to forget when headings change. Updating anchor links by hand is error prone, and a small typo can break navigation. The generator keeps your TOC synchronized with the headings in your content.

The tool is for people who write documentation, README files, tutorials, or technical blogs in Markdown. It works well for beginners who do not want to learn every detail of anchor formatting, and for experienced users who want a quick, reliable way to keep their TOC up to date. No programming is required beyond basic comfort with Markdown itself.

Background & Concept Explanation

Markdown is a plain text format for writing content with simple syntax for headings, lists, links, and more. Headings are written with one or more # characters at the start of a line, from H1 (#) to H6 (######). A table of contents is a list of links at the top of a document that point to these headings, making it easier for readers to jump to sections.

Most Markdown processors convert headings into HTML elements with id attributes derived from the heading text. For example, a heading like “## Install and setup” might become an h2 element with id="install-and-setup". A TOC entry for this heading uses a link to #install-and-setup. The exact rules for building ids differ between platforms such as GitHub, GitLab, and Bitbucket.

Manually writing a TOC means reading through your document, finding each heading, converting the text into the correct slug according to your platform’s rules, and then writing Markdown list items with proper indentation for different levels. When you rename a heading or change its level, you must remember to update the TOC. In practice, this often does not happen, and TOCs drift out of date.

The Markdown TOC Generator automates this process. It reads your content, finds headings within a configurable depth range, creates slugs using preset rules that mimic popular platforms, and outputs a formatted TOC. It also optionally skips code blocks to avoid picking up headings that appear inside fenced or inline code. An AI helper can suggest improved heading text to make your TOC clearer and more consistent.

Key Features

• Real-time heading parsing. The tool watches your Markdown input and, after a short delay, parses headings from the content. It works with up to one megabyte of input and up to fifty thousand lines, while protecting performance with sensible limits. If the document is empty, it clears the TOC.
• Configurable anchor presets. You can choose between presets for GitHub, GitLab, Bitbucket, and a generic URL style. Each preset uses its own slugging rules, such as stripping punctuation, replacing spaces with hyphens, or adding a markdown-header prefix. This ensures that TOC links match how your platform actually generates anchors.
• Depth control for headings. Settings allow you to control which heading levels appear in the TOC. You set a minimum and maximum depth between 1 and 6. For example, you can include only H1–H3 in the TOC and ignore deeper headings for a simpler structure.
• Code block exclusion. By default, the tool removes fenced code blocks (```…```) and inline code (`…`) before scanning for headings. This prevents false positives when code snippets contain lines starting with # that are not true headings.
• Markdown or HTML output. The generator can produce a Markdown list TOC or an HTML unordered list. Markdown output uses nested indentation with two spaces per level and builds items like - [Heading](#anchor). HTML output builds a ul list with escaped text and anchor tags pointing to the computed slugs.
• Input size and safety checks. The tool enforces a maximum input length of about one megabyte. If the content exceeds this limit, it shows a clear error message and stops processing. It also limits the number of lines examined to guard against memory issues in extremely large files.
• Copy to clipboard support. A Copy button copies the current TOC output to your clipboard when there is content. A small visual state change shows when the copy is successful, so you know it is ready to paste into your Markdown file.
• AI-powered heading refinement. An optional Optimize button calls an AI service that reviews your heading texts and suggests improvements. It returns a list of original and suggested headings with reasons, such as making them more concise, consistent, or descriptive. You can apply suggestions individually, and the tool updates the original Markdown content.
• Suggestion modal with apply actions. AI suggestions open in a dedicated modal dialog. Each suggestion shows the original heading (struck through), the improved version, and an explanation. An Apply button replaces the matching heading line in your Markdown while preserving the correct number of # characters.
• Settings panel for fine control. A settings panel lets you adjust anchor presets, depth range, whether to include HTML output, and whether to exclude code blocks. Changes take effect immediately and cause the TOC to regenerate on the next parse cycle.
• Error handling and status indicators. If parsing fails or input is too large, an error banner appears beneath the toolbar with a short message and a close button. Small indicators show character counts and parsing activity, for example when the tool is currently processing your input.

Common Use Cases

A documentation writer preparing a long user guide in Markdown can paste the entire file into the Markdown TOC Generator. The tool reads all H1–H3 headings, builds a nested TOC list, and the writer copies it into the top of the document. When new sections are added, they paste the updated content again and refresh the TOC in seconds.

A developer maintaining a project README wants a GitHub-compatible TOC. They select the GitHub preset, keep default depth settings, and paste their README text. The generator creates anchor links that match GitHub’s slug rules, including handling spaces and punctuation correctly. The developer can then paste the TOC back into the README, confident that links will work in the repository.

A technical blogger writing multi-part tutorials wants to ensure headings are consistent and well structured. They use the Optimize feature to get heading suggestions. After reviewing each suggestion and applying the ones they like, they regenerate the TOC so that the improved headings appear in a cleaner, more readable list.

A team writing internal standards for documentation uses the generator to show examples of good headings and matching TOCs. They paste in a sample document, show how changes to minDepth and maxDepth affect the TOC, and demonstrate HTML output for tools that require explicit HTML lists.

How to Use This Tool (Step-by-Step)

1. Open the Markdown TOC Generator. At the top of the page you will see a small toolbar with a settings button, an Optimize button, and a Copy button.
2. Click the settings icon if you want to adjust behavior. Choose an anchor preset (such as GitHub), set the minimum and maximum heading depth you want in the TOC, and toggle whether to exclude code blocks and whether to output HTML instead of Markdown list syntax.
3. In the editor section on the left, paste or type your Markdown content. Include headings using standard Markdown syntax: one or more # characters followed by a space and the heading text.
4. As you type or after pasting, watch the character counter. If you approach the maximum input size, the counter will help you avoid hitting the limit. When the tool is parsing, a small “Parsing…” indicator appears briefly.
5. After a short delay, the tool parses your content. It removes code blocks if that option is enabled, then scans line by line looking for heading lines that match the depth range. It builds an internal list of heading items with level, text, and slug.
6. Look at the Table of Contents panel on the right. If headings are found, the tool displays the generated TOC. For Markdown output, you will see a list of - [Heading](#slug) lines with indentation. For HTML output, you will see a ul list with link tags.
7. If no headings are detected, the right panel shows an empty state message prompting you to add headings. Check your content to make sure headings start at the beginning of a line with # characters.
8. When you are satisfied with the TOC, click the Copy button in the toolbar. If there is no output yet, the button is disabled. When copying succeeds, the button briefly shows a success state so you know the TOC is in your clipboard.
9. Paste the TOC into your Markdown file at the top, usually after the main title. Save your document. In your Markdown viewer or platform, clicking TOC links should scroll to the corresponding headings.
10. If you want help improving headings, click the Optimize button. The tool gathers all heading texts and sends them to the AI service, as long as there are no more than one hundred headings and each heading text is within the length limit.
11. Wait while the AI processes your headings. When suggestions are ready, a modal appears showing each original and suggested heading, along with a reason for the change.
12. For each suggestion you like, click Apply. The tool updates your original Markdown by replacing the heading text while preserving the heading level (# count). The suggestion disappears from the list once applied.
13. Close the suggestion modal when you are done. The main editor now contains the updated headings, and the TOC panel updates to reflect these changes automatically.

Calculations & Logic

The Markdown TOC Generator uses a clear parsing pipeline. First, it checks that the input is a non-empty string and does not exceed the maximum allowed length. It also limits the number of lines it will process to avoid memory problems on huge documents. If the input passes these checks, it prepares a version of the content—with optional removal of code blocks—specifically for heading detection.

Code block exclusion operates in two passes. It removes fenced code blocks by matching patterns starting with ``` and ending with the next ``` across multiple lines. It also removes inline code fragments enclosed in single backticks so that heading-like patterns in code are not mistaken for real headings.

Next, it splits the sanitized text into lines and loops through them. For each line, it applies a regular expression that matches one to six # characters at the start, followed by at least one space and some text. For a match, it computes the heading level from the number of # characters and trims the heading text.

The parser enforces that the heading level lies within the configured minDepth and maxDepth range. If it does, it creates a TOC item with level, original text, and a slug computed by the anchor preset function. The slug generator removes or encodes characters based on preset rules, lowercases the text, and normalizes spaces and hyphens. For example, GitHub style slugs remove non-word characters, replace spaces with hyphens, collapse multiple hyphens, and strip leading and trailing hyphens.

When formatting the TOC in Markdown mode, the tool first finds the minimum heading level among all items. It then computes indentation for each line as two spaces times (item.level - minLevel). It escapes square brackets in the heading text to avoid breaking link syntax, then writes a line in the form - [text](#slug). The lines are joined with newlines into the final output.

When formatting in HTML mode, the tool wraps all items in a single ul element. For each heading, it escapes special HTML characters in the text and writes a li with an anchor tag whose href is #slug and content is the escaped text. It does not currently nest lists by level in HTML mode; all items appear in one flat list.

The AI refinement logic validates the heading array before calling the backend. It ensures the number of headings does not exceed the limit and that each heading is a string of acceptable length. It then calls the AI service with the headings array and expects back an array of RefinedHeading objects containing original, suggested, and reason fields. The UI ensures that applying a suggestion only changes exact matches for that heading text and keeps the same heading level.

Reference Tables or Scales

Tips, Limitations & Best Practices

Keep your headings clear and descriptive. A good TOC reflects the outline of your document, so short but meaningful headings will make the TOC more useful. The AI suggestions can help polish wording, but the content and structure still depend on you.

Use a depth range that matches your document. For short documents, including all headings (H1–H6) can create a noisy TOC. For long, structured guides, focusing on top levels such as H1–H3 often makes navigation clearer.

Be aware that different platforms implement their own anchor logic. Always choose the preset that matches where your Markdown will be rendered. If you are unsure, test the generated TOC in your target environment to confirm links work as expected.

Do not paste extremely large files that exceed the documented limits. The tool is optimized for typical documentation and blog posts, not raw logs or huge exports. If your content is very large, consider splitting the document into smaller parts with their own TOCs.

Use the settings to exclude code blocks if your examples contain lines that look like headings. This keeps your TOC focused on actual sections of your document instead of code comments or sample markup.

After copying the TOC back into your Markdown, keep the original document under version control. When you change headings, regenerate the TOC in this tool and update it so documentation and navigation stay in sync.