Fibonacci Generator

Overview

The Fibonacci Generator has two modes that share one response shape. With `count` (1 to 1000) it returns that many terms. With `maxvalue` it returns every term that does not exceed the ceiling, with a hard stop at 5,000 terms. `startfrom` (0 to 10,000) advances the generator before output begins. At the default of 0 the sequence opens with 0, 1, 1, 2 and the leading 0 counts toward `count`; at any higher value the first term returned is F(startfrom + 1), so `startfrom=10` begins at 89.

Terms and the running `sum` are accumulated as exact big integers and converted to JSON numbers only when the response is built. A JSON number holds integers exactly only up to 2^53, so from F(79) onward the returned digits are the nearest representable value rather than the exact term, and beyond roughly F(1476) a term is too large for a number at all and serialises as null. For exact large values, use the sequence for its shape and compute the digits client-side.

`ratios` divides each term by the one before it, skipping any division by zero, rounds to six decimal places and keeps only the last five. `golden_ratio_approximation` is the final ratio, or null when the sequence is too short to form one, for example a single term. `first_value`, `last_value` and `count` describe the returned array, and `start_from` echoes the offset used.

Live Test Fibonacci Generator API →

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

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curl "https://api.apiverve.com/v1/fibonaccigenerator?count=10&startfrom=0" \
  -H "x-api-key: your_api_key_here"

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const res = await fetch('https://api.apiverve.com/v1/fibonaccigenerator?count=10&startfrom=0', {
  headers: { 'x-api-key': 'your_api_key_here' },
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

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import requests

res = requests.get(
    "https://api.apiverve.com/v1/fibonaccigenerator?count=10&startfrom=0",
    headers={"x-api-key": "your_api_key_here"},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

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package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/fibonaccigenerator?count=10&startfrom=0", nil)
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

Parameters

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them.

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

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{
  "status": "ok",
  "error": null,
  "data": {
    "sequence": [
      0,
      1,
      1,
      2,
      3,
      5,
      8,
      13,
      21,
      34
    ],
    "count": 10,
    "start_from": 0,
    "first_value": 0,
    "last_value": 34,
    "sum": 88,
    "ratios": [
      1.666667,
      1.6,
      1.625,
      1.615385,
      1.619048
    ],
    "golden_ratio_approximation": 1.619048
  }
}

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.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Use cases

Math Education

Teach Fibonacci sequences and golden ratio concepts in educational applications and tools

Algorithm Testing

Generate test data for algorithms and performance testing using Fibonacci sequences

Visual Design

Apply Fibonacci ratios and golden ratio proportions in design and layout calculations

Data Analysis

Use Fibonacci numbers in technical analysis, trading algorithms, and pattern recognition

Other ways to use Fibonacci Generator

Set up Fibonacci Generator on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Related

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