Leet Speak API

About the Leet Speak API

Pass any text string along with an encode or decode mode parameter. The engine replaces letters with numeric or symbolic equivalents when encoding, or restores standard Latin letters when decoding. Every response returns the converted text string, the applied mode, and the exact count of modified characters.

What people use it for

Content Moderation

Detect banned keywords hidden in community forum posts by decoding obfuscated characters into standard text before running profanity checks.

Username Duplicate Prevention

To catch duplicate registrations trying to bypass unique name rules using number substitutions, identity services normalize gamer handles before saving.

Gaming Chat Filters

In-game chat systems convert incoming player messages back into standard vocabulary to flag abusive behavior across multiplayer lobbies.

Retro Profile Styling

When generating novelty badges or cyberpunk titles, social applications convert usernames and status messages into stylized character strings.

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON

Default REST response

XML

Markup format

YAML

Human-readable

CSV

Tabular export

Beta

GraphQL

Query language

New

MCP

For AI agents

Request parameters — POST /v1/leetspeak

Sent as JSON in the request body. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

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curl -X POST "https://api.apiverve.com/v1/leetspeak" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text":"This is a simple piece of text","mode":"encode"}'

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Response — POST /v1/leetspeak

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

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{
  "status": "ok",
  "error": null,
  "data": {
    "text": "7h!5 !5 4 5!mp13 p!3c3 0f 73x7",
    "mode": "encode",
    "changedCharacters": 17
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

What a call costs — 2 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Zero-code embed — one snippet, no backend

Drop an interactive Leet Speak form onto any page. The widget calls the API for you, so no key ever appears in your markup and there is nothing to deploy.

Changelog — Leet Speak API

Every change to this endpoint, newest first. Breaking changes ship as a new version and the previous one keeps serving — response fields are added, never removed or retyped in place, so an integration written against v1 keeps working.

Currently v1