Automatically detect the language of untagged fenced code blocks and insert the language identifier. Supports TypeScript, Python, SQL, Bash, HTML, JSON, and more.
Free is enough for most one-off jobs. Pro raises the file and batch caps; Pro + Media unlocks GB-scale streaming and unlimited duration.
Larger files supported on Developer (5 GB CSV) and Enterprise (unlimited). All processing happens in your browser — files never reach a server.
Paste Markdown containing untagged ``` code fences
Heuristic detection identifies the language from content patterns (imports, syntax, keywords)
Download the updated Markdown with language tags added to previously untagged blocks
0 bytes uploaded. Code Block Language Tagger runs entirely in your browser using JavaScript. Your markdown — including any secrets, PII, or proprietary content — never leaves your device. No data is sent to any server.
TypeScript/JavaScript, Python, SQL, Bash/Shell, HTML, CSS, JSON, YAML, Java, Rust, Go, Ruby, PHP, C/C++, and Markdown itself. Detection is heuristic — it checks for language-specific keywords and patterns.
The tool adds a comment marker in cases of low confidence. You can review and correct tags manually after downloading.
Normalize AI-generated bullet chaos — •, ▸, ∙, 1), a) — into standard Markdown lists. Instant browser processing, no upload.
Open toolStandardise inconsistent math delimiters — \(, \[, $$, $ — into a single consistent format for web display with KaTeX or MathJax. Free, browser-based.
Open toolCheck Markdown against 15 markdownlint-compatible rules and get inline fix suggestions. Catches heading hierarchy, trailing whitespace, bare URLs, and more. Free.
Open tool