--- title: Server SDK Configuration Sources description: Understand how Datadog Feature Flags server SDKs receive flag configuration. breadcrumbs: Docs > Feature Flags > Concepts > Server SDK Configuration Sources --- > For the complete documentation index, see [llms.txt](https://docs.datadoghq.com/llms.txt). # Server SDK Configuration Sources {% callout %} # Important note for users on the following Datadog sites: app.ddog-gov.com, us2.ddog-gov.com {% alert level="danger" %} This product is not supported for your selected [Datadog site](https://docs.datadoghq.com/getting_started/site.md). ({% placeholder "user-datadog-site-name" /%}). {% /alert %} {% /callout %} Datadog Feature Flags [server-side SDKs](https://docs.datadoghq.com/feature_flags/server.md) evaluate flags locally from flag configuration. The *configuration source* determines how the SDK receives that configuration; it does not change OpenFeature evaluation semantics. ## Choose a configuration source{% #choose-a-configuration-source %} These configuration source options are available for supported server SDKs: {% dl %} {% dt %} `agentless` {% /dt %} {% dd %} The SDK periodically fetches flag configuration from the Datadog-managed CDN over HTTPS. - Polling begins when application code initializes or accesses the Datadog OpenFeature provider. - No Datadog Agent is required for flag configuration. {% /dd %} {% dt %} `remote_config` {% /dt %} {% dd %} The Datadog Agent receives flag configuration through Remote Configuration and delivers it to the SDK. - Selecting `remote_config` enables the Feature Flags Remote Configuration subscription. - Requires a Datadog Agent with Remote Configuration enabled. {% /dd %} {% /dl %} Agentless delivery is the default in supported SDK versions. Other server SDKs use Agent Remote Configuration for flag delivery. Set `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE` only when you want to select a source explicitly: ```bash DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=agentless ``` The SDK resolves the source once during initialization. Restart the application to change sources. ## Use agentless delivery{% #use-agentless-delivery %} To get started with agentless delivery, use one of these minimum versions: | SDK | Minimum version | | ----------------------------------------- | --------------- | | Java `dd-openfeature` and `dd-java-agent` | 1.65.0 | | Node.js `dd-trace` v5 | 5.116.0 | | Node.js `dd-trace` v6 | 6.5.0 | Java CDN delivery requires `dd-openfeature` and `dd-java-agent`. It does not require a Datadog Agent for flag configuration. Configure the API key, Datadog site, and environment in the application process: ```bash DD_API_KEY= DD_SITE= DD_ENV= ``` Then initialize or access the Datadog OpenFeature provider in application code. See the [Java](https://docs.datadoghq.com/feature_flags/server/java.md) or [Node.js](https://docs.datadoghq.com/feature_flags/server/nodejs.md) setup instructions. No configuration-source or provider-enable setting is required. Polling begins only when application code initializes or accesses the provider; installing or initializing the tracer alone does not create Feature Flags CDN traffic. {% alert level="warning" %} The initial Node.js agentless releases support configuration delivery and local flag evaluation only. They do not export evaluation metrics or exposure events. Java agentless delivery changes only the configuration source. Without a supported Datadog Agent or serverless telemetry path, Java also does not export these signals. {% /alert %} ### Configure agentless delivery{% #configure-agentless-delivery %} Set `DD_SITE` to your organization's Datadog site. For the site selected on this documentation page, use . The agentless source also supports these operational settings: | Environment variable | Default | Description | | ------------------------------------------------------------------------- | ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------ | | `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_BASE_URL` | Datadog-managed endpoint | Overrides the agentless flag configuration endpoint or base URL. See Use a custom agentless endpoint. | | `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_POLL_INTERVAL_SECONDS` | `30` | Positive integer that sets the time between completed polling attempts. Java does not limit attempts, while Node.js caps values at 3600 seconds. | | `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_REQUEST_TIMEOUT_SECONDS` | `5` | Positive integer that sets the timeout for an individual configuration request. | The SDK fetches configuration in the background and evaluates flags locally. Individual flag evaluations do not make network requests. The agentless source does the following: - Polls every 30 seconds by default - Uses a 5-second request timeout by default - Uses ETags to avoid downloading unchanged configuration - Preserves the last accepted configuration during temporary network or payload errors - Prevents overlapping polls The Datadog-managed CDN uses globally distributed points of presence, network peering, and redundant routing. Serving locations are therefore likely to be geographically close to most application workloads. Keep `DD_API_KEY` in a secret manager and expose it only to the application process that loads flag configuration. Agentless configuration delivery sends the API key directly from the application to Datadog over HTTPS. ### Use a custom agentless endpoint{% #use-a-custom-agentless-endpoint %} The Datadog-managed endpoint is recommended for standard deployments. For advanced testing, local development, or an operator-managed proxy, override it with `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_BASE_URL`: ```bash DD_FEATURE_FLAGS_CONFIGURATION_SOURCE_AGENTLESS_BASE_URL=http://localhost:8080 ``` The custom URL must use HTTP or HTTPS. If it contains only an origin or a root path, the SDK appends the standard flag configuration path. If it contains a non-root path, the SDK uses that path as the complete endpoint. The SDK sends `DD_API_KEY` only over HTTPS to the default Datadog-managed endpoint. It never forwards the Datadog API key to a custom endpoint. Custom endpoints can use HTTP for controlled local development; use HTTPS for any endpoint outside the local development environment. If the custom endpoint setting is invalid, the SDK keeps the provider disabled, logs the configuration error, and evaluations return caller-provided default values. Datadog-managed agentless delivery is not available for Datadog for Government in the supported SDK versions. Applications on that site continue to use caller-provided default values unless they use Agent Remote Configuration. ### Migrate an existing Remote Configuration setup{% #migrate-an-existing-remote-configuration-setup %} Existing customers who set `DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED=true` remain on Remote Configuration during a migration window. This deprecated setting is a compatibility bridge, not the long-term configuration. When you are ready to use agentless delivery: 1. Set `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=agentless`. 1. For the Datadog-managed endpoint, configure `DD_API_KEY`, `DD_SITE`, and `DD_ENV` in the application. 1. Initialize the provider and verify that it receives flag updates. 1. Remove `DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED`. Do not leave the deprecated setting enabled after the migration is complete. To remain on Agent Remote Configuration temporarily, set `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=remote_config`, then remove `DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED`. Your API key remains on the Agent. If you set `DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED=false`, replace it with `DD_FEATURE_FLAGS_ENABLED=false`. Explicit `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE` values take precedence over the legacy setting. After the legacy setting is removed, applications without an explicit source use agentless delivery. Set `remote_config` explicitly before the deprecated legacy setting is removed if you want to remain on Agent delivery. ## Use Agent Remote Configuration{% #use-agent-remote-configuration %} Set the source to `remote_config` to use Agent-managed delivery: ```bash DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=remote_config ``` For Java, Remote Configuration requires compatible `dd-openfeature` and `dd-java-agent` versions. Use version 1.65.0 or later for both components. Configure the API key on the Agent, not in the application process. If Remote Configuration has been disabled on the Agent, re-enable it. See [Remote Configuration](https://docs.datadoghq.com/remote_configuration.md) for Agent setup and network requirements. ## Advanced configuration{% #advanced-configuration %} ### Enable or disable feature flags{% #enable-or-disable-feature-flags %} `DD_FEATURE_FLAGS_ENABLED` defaults to `true`, so new setups do not need to set it. Set it to `false` to disable the provider and both configuration delivery paths: ```bash DD_FEATURE_FLAGS_ENABLED=false ``` ### Activation and billing{% #activation-and-billing %} Server Feature Flags billing is based on configuration requests made through Remote Configuration or the CDN. Installing the tracer does not activate either delivery path by itself. - With the default agentless source, CDN polling starts only when application code initializes or accesses the Datadog OpenFeature provider. - Explicitly selecting `remote_config` starts the Agent Feature Flags subscription. It does not require application code to initialize the provider. ### Configuration precedence{% #configuration-precedence %} | Configuration | Result | | ------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------- | | `DD_FEATURE_FLAGS_ENABLED=false` | Disables the provider and both delivery paths, regardless of other settings. | | Explicit `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=agentless` | Selects CDN delivery. Polling begins when application code initializes or accesses the provider. | | Explicit `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=remote_config` | Selects Agent delivery and enables the Feature Flags Remote Configuration subscription. | | Blank or whitespace-only `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE` | Treats the source as unset, so the legacy migration setting or the agentless default applies. | | Explicit `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE=offline` or another unsupported nonblank value | Fails closed when application code accesses the provider. The SDK does not select CDN or Remote Configuration delivery. | | No source and `DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED=true` | Preserves Remote Configuration during the migration window. | | No source and `DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED=false` | Keeps the provider and both delivery paths disabled. | | Neither `DD_FEATURE_FLAGS_CONFIGURATION_SOURCE` nor `DD_EXPERIMENTAL_FLAGGING_PROVIDER_ENABLED` is set | Selects agentless delivery. Polling begins when application code initializes or accesses the provider. | ## Further reading{% #further-reading %} Additional helpful documentation, links, and articles: - [Set up Server-Side Feature Flags](https://docs.datadoghq.com/feature_flags/server.md) - [Use Feature Flags in serverless environments](https://docs.datadoghq.com/feature_flags/implementation_patterns/serverless.md) - [Learn about Remote Configuration](https://docs.datadoghq.com/remote_configuration.md)