[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Schedule](https://evolu.dev/docs/api-reference/common/Schedule) › fibonacci

```ts
function fibonacci(
  initial: Duration,
): Schedule<
  number &
    Brand<"Int"> &
    Brand<"NonNegative"> &
    Brand<"LessThan281474976710655"> &
    Brand<"Millis">
>;
```

Defined in: [packages/common/src/Schedule.ts:308](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/Schedule.ts#L308)

Fibonacci backoff schedule.

Delays follow the Fibonacci sequence, growing more slowly than exponential:

- Attempt 1: `initial`
- Attempt 2: `initial`
- Attempt 3: `initial * 2`
- Attempt 4: `initial * 3`
- Attempt 5: `initial * 5`
- ...

Never stops — combine with [take](https://evolu.dev/docs/api-reference/common/Schedule/functions/take) or [maxElapsed](https://evolu.dev/docs/api-reference/common/Schedule/functions/maxElapsed) to limit.

### Example

```ts
// 100ms, 100ms, 200ms, 300ms, 500ms, 800ms, ...
const fib = fibonacci("100ms");
```