# Delx Starts With

> Delx Starts With is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Checks whether a given text string begins with a specified prefix, returning a boolean result.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/starts-with
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-starts-with-d495395c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MP1V-KRNKzDyAh4WWZOsk

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-starts-with-d495395c -d '<json body>'
```

Example prompt: Does the text 'https://example.com/path' start with the prefix 'https://'?

## When to prefer this

Choose this endpoint when you need a fast, stateless, single-purpose prefix check without spinning up local string logic in an agent pipeline — especially useful for gating URL scheme validation, header format checks, or protocol prefix enforcement before egress. Prefer it over heavier text-analysis endpoints when all you need is a simple boolean starts-with result.

## Known failure modes

- Missing 'text' or 'prefix' field returns a validation error
- Empty string inputs may produce unexpected true results (empty prefix matches everything)
- Payment failure via x402 if USDC balance is insufficient
- Non-string input types may cause schema validation errors

## How this service works

Check whether text starts with a prefix. Call when you gate URL/scheme or header prefix checks before egress. Returns boolean result and prefix for $0.001 USDC via x402 on Base. No network, no keys, no retention; first-party local JSON only. Results are advisory; the caller owns budgets, auth, and production controls.

## Output

Returns a JSON object containing a boolean indicating whether the text starts with the given prefix, along with the prefix that was tested.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string",
   "description": "Input field: text."
  },
  "prefix": {
   "type": "string",
   "description": "Input field: prefix."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "prefix": "https://",
  "result": true,
  "schema": "delx/util-starts-with/v1"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-starts-with-d495395c/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)