AppConfigData — AWS AppConfig Data Plane

AWS docs: https://docs.aws.amazon.com/appconfig/2021-11-11/APIReference/

AWS AppConfigData is the runtime data plane for AppConfig. Applications use it to retrieve the latest deployed configuration content via a poll-based session model.

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Protocol

AppConfigData is a REST-JSON service, served at the two bindings AWS models:

POST /configurationsessions
GET  /configuration?configuration_token={token}

The configuration token is a query parameter, not a path segment — that is how every AWS SDK sends it.

Session lifecycle

1. Call StartConfigurationSession with your application, environment, and configuration profile identifiers (name or ID both work). Optionally set RequiredMinimumPollIntervalInSeconds (15–86400) to constrain how often the session may be polled.
2. Use the returned InitialConfigurationToken as configuration_token on GetLatestConfiguration.
3. Each GetLatestConfiguration response includes a Next-Poll-Configuration-Token header — you must use this token for all subsequent polls. Tokens are single-use, rotate on every call, and expire 24 hours after they are issued.
4. When no new version has been published since the last successful delivery, GetLatestConfiguration returns HTTP 200 with an empty payload. This matches the AWS behaviour that prevents well-behaved polling SDKs from re-applying unchanged config.

Response headers from GetLatestConfiguration

Header	Value
Next-Poll-Configuration-Token	New opaque token (UUID)
Next-Poll-Interval-In-Seconds	The session’s RequiredMinimumPollIntervalInSeconds, else 60
Content-Type	As stored in the hosted version (e.g. application/json)

The configuration itself is the response body. Version-Label is modeled here too and is never sent: it carries the hosted configuration version’s user-defined label, which Overcast’s AppConfig control plane does not store, and AWS omits it when there is none.

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Relationship to AppConfig control plane

Configuration content is stored through the AppConfig control-plane API:

POST /applications/{app}/configurationprofiles/{profile}/hostedconfigurationversions

That request must carry an appconfig SigV4 credential scope: /applications is shared with Service Catalog AppRegistry — see appconfig.md.

AppConfigData reads that stored content — both services must be enabled (they are by default).

Summary

Category	✅ Supported
Sessions	2

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Endpoints

Sessions

Operation	Status	Notes	AWS Docs
StartConfigurationSession	✅ Supported	Starts a polling session; returns InitialConfigurationToken; honours RequiredMinimumPollIntervalInSeconds	docs
GetLatestConfiguration	✅ Supported	Takes the token as the configuration_token query parameter; returns the configuration as the response payload with the session state in headers; empty payload when unchanged since the last poll	docs