nvim-inline-markdown

Clean, toggleable inline markdown rendering for Neovim — with mermaid diagrams rendered as real images inside your buffer.

• Headings with icons and subtle backgrounds, styled bullets and checkboxes, code block backgrounds with language labels, box-drawing table borders, quote bars, concealed **bold** / *italic* / `code` / ~~strike~~ / link / <autolink> syntax
• GFM alerts (> [!NOTE], [!TIP], [!IMPORTANT], [!WARNING], [!CAUTION]) rendered as colored icon badges with matching quote bars
• Two style presets: default (icons + heading backgrounds) and github (underlined h1/h2, ▎ accent bars, closed table borders with header shading — closest to GitHub's web rendering)
• ```mermaid blocks are rendered to PNG via mermaid-cli (async, content-hash cached) and displayed inline below the block via image.nvim
• Toggle-centric UX: :InlineMarkdown toggle (default <leader>mp) switches between rendered view and plain text; while enabled, edits re-render automatically (debounced), and only changed diagrams are re-generated
• Broken diagrams show the mmdc error inline instead of retrying forever

Requirements

• Neovim ≥ 0.10 with markdown / markdown_inline treesitter parsers
• mermaid-cli: npm i -g @mermaid-js/mermaid-cli
• image.nvim + ImageMagick (brew install imagemagick)
• A terminal with image support (kitty, ghostty, WezTerm, …).
  • WezTerm: enable_kitty_graphics = true
  • tmux: set -gq allow-passthrough on

Everything degrades gracefully: without mmdc or image.nvim you still get full text styling. Run :checkhealth inline-markdown to diagnose your setup.

Installation

lazy.nvim / AstroNvim

{
  "minsuhya/nvim-inline-markdown",
  ft = "markdown",
  dependencies = {
    {
      "3rd/image.nvim",
      opts = {
        processor = "magick_cli",
        integrations = { markdown = { enabled = false } },
        max_width_window_percentage = 80,
      },
    },
  },
  opts = {},
}

Usage

Command	Action
:InlineMarkdown / :InlineMarkdown toggle	Toggle rendering for the current buffer
:InlineMarkdown enable / disable	Explicit on / off
:InlineMarkdown refresh	Force re-render (also retries failed diagrams)

Default keymap: <leader>mp in markdown buffers.

Configuration (defaults)

require("inline-markdown").setup({
  file_types = { "markdown" },
  render_on_open = false,      -- auto-enable when opening markdown files
  keymap = "<leader>mp",       -- false to disable
  debounce_ms = 300,
  win_options = { conceallevel = 2, concealcursor = "nc" },
  style = {
    preset = "default",        -- "default" | "github"
    headings = { icons = { "󰲡 ", "󰲣 ", "󰲥 ", "󰲧 ", "󰲩 ", "󰲫 " }, background = true, bar = "▎" },
    bullets = { "●", "○", "◆", "◇" },
    checkbox = { unchecked = "󰄱 ", checked = "󰱒 " },
    code = { background = true, language_label = true },
    quote = { icon = "▍" },
    link = { icon = "󰌹 " },
    rule = { char = "─", width = 80 },
    table_borders = true,
    conceal_inline = true,
  },
  mermaid = {
    enabled = true,
    mmdc_path = "mmdc",
    theme = "auto",            -- follows vim.o.background; or "dark"|"default"|"forest"|...
    background = "transparent",
    width = 1200,
    scale = 2,
    max_jobs = 2,
    extra_args = {},
  },
})

All InlineMarkdown* highlight groups are defined with default = true and can be overridden by your colorscheme.

Notes

• Rendered PNGs are cached in stdpath("cache")/inline-markdown/ keyed by a hash of the diagram source and theme settings; unchanged diagrams never re-invoke mmdc.
• Diagrams are shown below their source block (the styled source stays visible), so you can keep editing while seeing the result.

License

MIT