# ReadX — Get Usernames by User ID

> ReadX — Get Usernames by User ID is a paid API for AI agents from readx.sh, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Looks up X/Twitter usernames (handles) for one or more numeric user IDs, returning a mapping of ID to username.

## Facts

- Endpoint: GET https://readx.sh/api/tools/get_usernames
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/readx-get-usernames-by-user-id-14df7424
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_r7eYUt_HlB7Cb863_TkwI

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability readx-get-usernames-by-user-id-14df7424
```

Example prompt: What's the X/Twitter username for user ID 44196397? Use ReadX to look it up without needing an API key.

## When to prefer this

Use this endpoint when you have numeric X/Twitter user IDs and need to resolve them to human-readable usernames, without requiring X API credentials. Ideal for enriching datasets, analytics pipelines, or any workflow that surfaces raw X user IDs. Prefer over official X API when you want pay-per-call micropayment access with no key management.

## Known failure modes

- Invalid or non-existent user ID returns null for that entry
- Malformed request returns a non-zero error code
- Payment failure (x402) if USDC balance is insufficient — endpoint returns 402 before processing
- Rate limits or upstream X API unavailability may cause transient errors

## How this service works

Resolve up to 20 numeric user ids to @usernames (map; null on per-id failure). Example: GET /api/tools/get_usernames?user_ids=12,44196397

## Output

A JSON object with a 'data' field mapping numeric user IDs (as string keys) to their current X/Twitter usernames (handles). Null values indicate IDs that could not be resolved. Also returns a 'code' field (0 on success).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "required": {
   "type": "string"
  },
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "code": 0,
  "data": {
   "0": null,
   "12": "jack",
   "44196397": "elonmusk"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/readx-get-usernames-by-user-id-14df7424/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from readx.sh](https://www.zero.xyz/host/readx.sh/llms.txt)