Compute resource limits
Last updated 2024-03-12
This guide details Fastly resource limits for Compute services. These limits change based on whether or not you've purchased one of our packaged offerings or you're using a trial account.
NOTE
In addition to the limits described here, Compute services can also be limited by the products or platform services that you access through your application code. Check out our network services resource limits for additional details.
Port limits
Compute services accept client connections on port 443 only. This is different from VCL services, which support client connections on port 80.
NOTE
If your Compute service receives a request on port 80, Fastly automatically returns a 308 Permanent Redirect response status with the Location header indicating the HTTPS version of the same URL in a Location header.
Default limits
Limits marked with an asterisk (*) can be adjusted in code using the limits interface in your preferred software developer kit (SDK). Contact support to discuss raising any other limits.
| Item | Limit | Scope |
|---|---|---|
| Maximum compiled package size | 100MB | per service |
| Maximum cached object size | 100MB | per object |
| Maximum CPU time available to a single request instance | 50ms | per execution |
| Maximum runtime for a single request instance | 2 min (60s for trial accounts) | per execution |
| Maximum memory consumption | 1M bytes stack, 128MB heap | per execution |
| Maximum number of dictionary lookups | 16 | per execution |
| Maximum number of backend requests | 32 (10 for trial accounts) | per execution |
| Vary rules | 8 | per cache object |
| Maximum length of a header name | 8192 bytes* | per header |
| Maximum length of a header value | 8192 bytes* | per header |
| Maximum length of a method name | 8192 bytes* | per request |
| Maximum length of a URL | 8192 bytes* | per request |
An execution refers to a single instance of a Compute program being executed, normally in response to a client HTTP request. Separate limits also apply to the use of log tailing with Compute services.
Service chain limits
| Item | Limit | Implications |
|---|---|---|
| Service chains and hops | 20 hops, 6 unique services | Read our developer information about loop detection for more info. |
Edge data storage limits
Limits for each of our edge data storage options differ if you've purchased a package offering or are using a product or feature trial.
Config Store
Config Store is included with your Compute service with the following limitations.
| Item | Trial limit | Paid account limit | Implications |
|---|---|---|---|
| Config stores | 1 | 5 | Paid accounts can purchase additional stores for a monthly fee. |
| Config store entries (per store) | 100 | 500 | An error informs you that you've exceeded the limit. |
| Config store key length | 255 characters | 255 characters | An error informs you that you've exceeded the limit. |
| Config store key value length | 8,000 characters | 8,000 characters | An error informs you that you've exceeded the limit. |
| Config store write operations | 100 writes per hour | 100 writes per hour | Write limits are shared with all other Fastly API calls. Exceeding the limit will result in an API limit error. Refer to API rate limiting for more info. |
KV Store
KV Store is an add-on and is priced in addition to Compute services. The following limitations apply:
- The number of KV stores you can create is limited to your account’s available resources allotment.
- KV store names have a maximum length of 255 bytes in UTF-8 format.
- KV stores have a rate limit of 1,000 writes per second per store, and 5,000 reads per second per store.
- KV store items support a maximum key length of 1024 bytes in UTF-8 format.
- KV store items have a rate limit of 1 write per second.
- KV store item batch requests have a limit of 100,000 items per request.
- KV stores support values submitted using any file type and have a maximum size of 25MB. This maximum can be raised to 100MB upon request. Contact your account manager or sales@fastly.com for more information.
Do not use this form to send sensitive information. If you need assistance, contact support. This form is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
