# Environments

Model runtime boundaries, configuration readiness, and environment lifecycle.

An environment is a runtime boundary inside one project. Flags have independent fallbacks, rules,
client exposure, and emergency state in each environment. Evaluation keys bind to one environment.

Use environments for deployed boundaries that need independent values and credentials. Do not use
them as a promotion queue, release checklist, or substitute for deployment automation.

## Design the environment set

`development`, `staging`, and `production` are useful defaults when they match real runtime stages.
Create custom environments only when they correspond to another durable runtime boundary.

| Model                 | Use it when                                              | Avoid it when                               |
| --------------------- | -------------------------------------------------------- | ------------------------------------------- |
| Standard environments | The application has development, staging, and production | Those names do not map to real runtimes     |
| Regional environment  | Regions are deployed and operated independently          | Region is only a targeting attribute        |
| Preview environment   | It is a durable runtime with owned credentials           | A short-lived branch can use bootstrap data |

FeatureGate does not copy configuration from staging to production. Apply each production change
deliberately so a non-production experiment cannot become production configuration accidentally.

Environment keys are immutable because credentials, audit events, and URLs depend on them. Use a
stable machine key and reserve the display name for wording that may change.

## Configuration and readiness

Creating an environment seeds configurations for existing flags. Review the generated values before
traffic. A ready environment progresses through these states:

1. Create or restore the environment.
2. Ensure at least one active flag exists.
3. Review the fallbacks seeded for the environment.
4. Create a server runtime key with the required scopes.
5. Send the first hosted request.
6. Review default warnings after real traffic.

An all-off fresh environment is not automatically risky before it serves traffic. After the first
hosted request, fallback review becomes operationally relevant.

Client keys add two requirements: allowed origins and explicit client exposure on each flag. A client
key does not make every environment flag browser-readable.

## Manage keys and configuration

Open the project **Environments** page and select an environment by its URL path. Create, list, and
revoke runtime keys from that boundary. Raw secrets are shown once and cannot be recovered.

Missing configurations can occur after deliberate unconfiguration. A configured boolean `false`
differs from a missing configuration: `false` is a valid result and may still be overridden by rules.

## Archive and delete

Archive is reversible and prevents new normal use while preserving history. Restore the environment
before creating keys or changing active configuration.

Permanent deletion is available only after archive. Before deletion, replace callers, confirm safe
caller defaults, and allow snapshot clients to refresh or shut down.

A running SDK may retain its last successful in-memory snapshot until refresh, restart, or shutdown.
An environment lifecycle change is not a remote memory wipe.

## Diagnose environment problems

- **No flags:** create a flag after confirming the environment is active.
- **Missing defaults:** configure every required flag with the correct type.
- **No runtime key:** create one and store its one-time secret immediately.
- **No first request:** send a hosted evaluation or snapshot request with the bound key.
- **Review defaults:** inspect fallbacks after hosted traffic establishes relevance.
- **Stale value:** wait for a successful refresh or call `refresh()`.

Related pages: [Evaluation credentials](/docs/evaluate/credentials),
[Environment readiness](/docs/operate/environment-readiness), and
[Configure flags across environments](/docs/flags/environment-configuration).