tldx

What is tldx?

tldx is a command-line tool for bulk domain availability checking. It takes one or more keywords, generates candidate domain names using prefixes, suffixes, TLD selections, presets, or regex-based patterns, and checks whether those domains are available using RDAP, DNS, and WHOIS data sources.

It is designed for fast brainstorming and filtering of domain ideas from the terminal. Results can be streamed as they are found, limited to available domains only, or exported in several formats for downstream use. The tool also includes an MCP server mode for agent-based workflows.

Key Features

• Bulk availability checks across multiple domains, with concurrent lookup behavior and support for RDAP-based checking.
• Keyword permutation controls for adding prefixes and suffixes, making it easier to explore brandable combinations from a single seed term.
• Regex-driven domain generation for pattern-based searches, such as generating short alphabetic combinations within a specific TLD set.
• Built-in and custom TLD presets, which let users reuse curated TLD groups instead of typing long TLD lists each time.
• Multiple output formats, including text, JSON, JSON stream, JSON array, CSV, grouped, and grouped-by-TLD layouts for different workflows.
• Filtering and control flags such as showing only available domains, limiting results, setting maximum domain length, running a dry run, and reading input from a file or stdin.
• MCP server support via tldx mcp, which allows the tool to be used by AI agents over stdio.

How to Use tldx

Start by passing one or more keywords on the command line, then add flags to control how candidate domains are generated and checked. For example, you can supply prefixes and suffixes, choose specific TLDs or a preset, or enable regex mode for pattern-based generation.

Typical usage involves running a check, reviewing the streamed results, and optionally narrowing output with --only-available, --limit, or a chosen format. Users who want reusable TLD groups can create presets with the preset subcommand, while automation users can read keywords from a file or stdin.

Use Cases

• A founder or side-project builder can test a product name across multiple extensions and quickly see which combinations are still available.
• A naming researcher can generate many domain variants from one seed word by adding prefixes and suffixes, then filter to only available results.
• A power user can search for pattern-based names, such as short letter-only domains, using regex mode and a curated TLD set.
• A team can define custom TLD presets for a shared naming workflow so common extension groups do not need to be re-entered each time.
• An AI agent or scripted workflow can call the MCP server to integrate domain checking into a larger automated naming process.

FAQ

Does tldx only check one domain at a time?
No. It is built for bulk checking, so it can process multiple keywords, permutations, and TLDs in one run.

What sources does it use to check availability?
The page states that tldx checks availability via RDAP, DNS, and WHOIS.

Can I output results in machine-readable formats?
Yes. The documented output formats include JSON, JSON stream, JSON array, CSV, grouped, and grouped-tld, in addition to plain text.

Can I save common TLD groups for reuse?
Yes. The preset subcommand supports adding, listing, and removing custom TLD presets stored in the user config directory.

Does it support AI-agent workflows?
Yes. The repository documents an MCP server mode started with tldx mcp.

Alternatives

• Browser-based domain search tools: better for quick one-off checks in a graphical interface, but they usually offer less control over permutations, regex generation, and output formatting.
• Registrar search interfaces: useful for registering a domain immediately, but they are typically narrower in workflow and less suited to bulk pattern exploration.
• Other command-line domain generators/checkers: similar in spirit, but may differ in whether they support regex-based generation, custom TLD presets, or structured output formats.
• General naming tools: helpful for brainstorming brand ideas, but they are usually broader in scope and do not focus specifically on domain availability verification.