---
title: ratelimit.ratecounter_increment
summary: null
url: >-
  https://www.fastly.com/documentation/reference/vcl/functions/rate-limiting/ratelimit-ratecounter-increment
---

```
INTEGER ratelimit.ratecounter_increment(ID rc, STRING entry, INTEGER delta)
```

**Available in:** all subroutines

Increment an entry in a ratecounter and and check if the client has exceeded
some average number of requests per second.

For rate limiting purposes, consider using the `ratelimit.check_rate` and
`ratelimit.check_rates` functions instead, which correctly handle the necessary
details.

## Parameters

`rc` - The ratecounter that tracks requests. When a user makes a request, a
ratecounter tracks that users average rate of requests over time.

`entry` - The entry to keep track of. Typically `client.ip`, and any associated
metadata. An entry can be, at maximum, 256 bytes long.

`delta` - The integer value to increment the entry in the rate counter by.
Typically, a value of 1 is used. The value must be between 0 and 1000.

## Return value

Upon completion, this function returns an integer representing the total number
of estimated increments for `entry`, received in the given POP, over the last 1
minute.

In the event an error occurs, the default return value is `false`; therefore
errors (via `fastly.error`) must be handled specifically.

## Errors

If the given `entry` is longer than 256 bytes, then `false` is returned, and
`fastly.error` is set to `EINVAL`.

## Example

The following example will increment the `entry` in the ratecounter `rc` by 10
for every response delivered to the client, as identified by their IP. It will
also set the HTTP header `X-Last-60s-Hits` to contain the total hits seen for
that IP over the last minute.

```vcl
ratecounter rc { }

sub vcl_deliver {
  declare local var.last_minute INTEGER;
  set var.last_minute = ratelimit.ratecounter_increment(rc, client.ip, 10);
  set resp.http.X-Last-60s-Hits = var.last_minute;
}
```