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GET
Evaluate Experiments

Authorizations

Authorization
string
header
required

An Account API key, an App API key, an account access token, an account-scoped user token, or a user OAuth token. Prepend the key or token with Bearer, for example Bearer ***************************. See Auth & API keys for how to get each one.

Headers

Api-Version-Date
string

Pins the request to a dated API version.

Example:

"2026-09-29"

Query Parameters

subject
object

Bucketing subject. Ownership is the top-level account_id. Account experiments accept caller-supplied subject IDs; internal experiments derive the user from the session.

Restricts batch evaluation to this related resource; omitted batches contain only unbound experiments.

flag_key
string

Flag or experiment to evaluate — the flag_key handle or the expt_ id. Omit to return all flags the caller qualifies for.

account_id
string

Owning account ID or internal. Required when evaluating by flag_key or in a batch; optional for an expt_ ID.

log_exposure
boolean

Set false to evaluate without recording an exposure. Omitted records it.

Response

200 - application/json

single flag evaluated

enabled
boolean
required

Whether the subject receives a treatment or enabled feature flag.

Example:

true

variant
string | null
required

Treatment name, control, or null for an inactive flag or excluded subject.

Example:

"treatment"

configuration_revision
integer
experiment_id
string

Unique experiment ID, included for account experiments.

flag_key
string

Present when evaluating a single experiment.

Example:

"checkout_redesign"