# Delx Fibonacci

> Delx Fibonacci 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).

Computes the Nth Fibonacci number for integer n up to 78, returning a structured JSON receipt for a micropayment of $0.001 USDC.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/fibonacci
- 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-fibonacci-03b4326e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bVQrX9RdznTcvZWPVlYdX

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-fibonacci-03b4326e -d '<json body>'
```

Example prompt: What is the 42nd Fibonacci number? Just give me F(42) as a clean structured result.

## When to prefer this

Choose this endpoint when you need a reliable, server-side computation of a Fibonacci number without shipping or maintaining a math library in your agent's runtime. Ideal for test fixtures, demos, or pipeline steps that need a deterministic integer value. Prefer it over local computation when you want a first-party signed receipt to prove the result. Not suited for computing sequences beyond index 78 or for bulk generation of many Fibonacci numbers in a single call.

## Known failure modes

- n out of range (n > 78 or n < 0): returns a structured validation error and no charge is applied
- non-integer input for n: returns a validation error with no billing
- missing n field: returns a structured error, no charge
- payment failure or insufficient USDC balance: call does not proceed

## How this service works

Nth Fibonacci (n≤78). Use for sequences, demos, or test fixtures without shipping a math package. Returns F(n) for n up to 78 with a structured receipt. $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

Returns a structured JSON object containing the input index n, the computed Fibonacci value F(n), and a receipt confirming the successful call. No extraneous data; deterministic and consistent across calls for the same n.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "n": {
   "type": "integer",
   "description": "Integer input (see tool summary for allowed range)."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "n": 42,
  "value": 267914296,
  "schema": "delx/fibonacci/v1"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-fibonacci-03b4326e/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)