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Vercel Edge Config

An Edge Config is a global data store that enables experimentation with feature flags, A/B testing, critical redirects, and more.
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Edge Config is available on all plans

An Edge Config is a global data store that enables experimentation with feature flags, A/B testing, critical redirects, and IP blocking. It enables you to read data at the edge without querying an external database or hitting upstream servers.

With Vercel's optimizations, you can read Edge Config data at negligible latency. The vast majority of your reads will complete within 15ms at P99, or as low as 0ms in some scenarios.

You can use an Edge Config in Edge Functions, Edge Middleware, and Serverless Functions.

Vercel's Edge Config read optimizations are only available on the Edge and Node.js runtimes. Optimizations can be enabled for other runtimes, such as Ruby, Go, and Python upon request. See our Edge Config limits docs to learn more.

Edge Configs are great for data that is accessed frequently and updated infrequently. Here are some examples of storage data suitable for Edge Config:

Feature flags and A/B testing: Experiment with A/B testing by storing feature flags in your Edge Config. Fetching such data from Edge Config rather than a database can cut page loads by hundreds of milliseconds. Deploy the template

Critical redirects: When you need to redirect a URL urgently, Edge Configs offer a fast solution that doesn't require you to redeploy your website. Using Edge Middleware, you can read from your Edge Config to redirect users when they visit bad URLs. Deploy the template

Malicious IP and User Agent blocking: Store a set of malicious IPs in your Edge Config, then block them upon detection without invoking upstream servers

You can create and manage your Edge Config from either Vercel REST API or Dashboard. You can scope your Edge Configs to your Hobby account or team, and connect them to as many projects as you want.

To get started, see our quickstart.

If you'd like to know whether or not Edge Config can be integrated into your workflow, it's worth knowing the following:

  • You can have one or more Edge Configs per Vercel account, depending on your plan as explained in Limits
  • You can use multiple Edge Configs in one Vercel project
  • Each Edge Config can be accessed by multiple Vercel projects
  • Edge Configs can be scoped to different environments within projects using environment variables
  • Edge Config access is secure by default. A read access token is required to read from them, and an API token is required to write to them

See our Edge Config limits docs to learn more

There are alternative solutions to Edge Config for handling A/B testing, feature flags, and IP blocking. The following table lays out how those solutions compare to Edge Config:

Edge Config vs alternativesRead latencyWrite latencyRedeployment requiredAdded risk of downtime
Edge ConfigUltra-low Varies No No
Remote JSON filesVaries VariesNo Yes
Embedded JSON filesLowestHighest Yes No
Environment VariablesLowestHighest Yes No

To learn about Edge Config limits and pricing, see our Edge Config limits docs.

Last updated on April 13, 2024