# Delx Mask Sensitive Strings

> Delx Mask Sensitive Strings is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Masks the middle characters of a sensitive string (e.g. tokens, account numbers, secrets) returning a partially-hidden version safe for logging and audit trails.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/mask-string
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-mask-sensitive-strings-b6d4a5f4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EfruX99L0xHUet_w6Vlw-

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 delx-mask-sensitive-strings-b6d4a5f4 -d '<json body>'
```

Example prompt: Before you log that API token, mask the sensitive middle characters so it's safe for the audit trail — the token is sk-abc123xyz789fullsecretvalue.

## When to prefer this

Choose this endpoint when you need a deterministic, stateless, first-party masking of sensitive strings for logging or audit purposes without storing the original. Prefer it over client-side masking when you want a consistent, auditable masking format across agents; prefer it over general text-redaction tools when you specifically need middle-character masking rather than full removal or regex-based scrubbing.

## Known failure modes

- String exceeds 100,000 character limit — request rejected with validation error (not billed)
- Empty or missing text field — structured validation error returned (not billed)
- Payment not provided or insufficient — x402 payment required response
- Network timeout on the x402 payment flow

## How this service works

Mask sensitive middle characters. Use before logging secrets, account numbers, or tokens that must stay partially hidden. Returns a masked string suitable for audit trails—never stores the original beyond the request. $0.001 USDC per successful call via x402 on Base—deterministic first-party JSON, no API key, no subscription, and nothing is billed on structured validation errors.

## Output

A masked string where the middle characters are replaced with masking characters (e.g. asterisks), leaving a prefix and suffix visible. The result is safe for inclusion in logs, audit trails, and display without exposing the full sensitive value. The original string is never retained beyond the request.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string",
   "maxLength": 100000,
   "description": "Primary text input (max 100k chars). Processed first-party; not retained as a dataset."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "text": "he*************ld",
  "schema": "delx/mask-string/v1",
  "source_len": 17
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-mask-sensitive-strings-b6d4a5f4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)