API REFERENCE

Statements

/xapi/statements

The Statements resource is the core of the xAPI spec. All learning events are stored here as immutable records. Statements can be submitted one at a time or in batches, and queried by any combination of actor, verb, activity, and time range.

POST Submit Statement(s)

Submit one statement (object) or multiple statements (array). Returns an array of assigned or confirmed statement IDs. Statements whose id is already stored are skipped and their ID still appears in the response — resubmitting a batch never conflicts, so retry loops are guaranteed to drain. Max 250 statements per request; 120 requests per minute per credential.

http

POST /xapi/statements
Authorization: Basic <base64(key:secret)>
Content-Type: application/json
X-Experience-API-Version: 1.0.3

// Single:
{
  "actor":  { "objectType": "Agent", "mbox": "mailto:student@school.edu" },
  "verb":   { "id": "http://adlnet.gov/expapi/verbs/completed", "display": { "en-US": "completed" } },
  "object": { "objectType": "Activity", "id": "https://your-game.com/level-1" }
}

// Batch (array):
[{ ... }, { ... }]

http

// 200 OK — statement(s) accepted
["550e8400-e29b-41d4-a716-446655440000"]

// 400 Bad Request — body: { "message": "actor is required" }
// 401 Unauthorized
// 413 Payload Too Large — more than 250 statements in one request
// 429 Too Many Requests — rate limit (120 requests/min per credential)

GET Query Statements

Retrieve statements matching the given filters. Returns a StatementResult object with a more URL for pagination.

Parameter	Type	Description
statementId	UUID	Fetch a single statement by ID. Cannot be combined with other filters.
agent	JSON	Filter by actor. E.g. {"mbox":"mailto:x@y.com","objectType":"Agent"}
activity	IRI	Filter by object activity ID.
verb	IRI	Filter by verb ID.
since	ISO 8601	Stored timestamp after this datetime (exclusive).
until	ISO 8601	Stored timestamp before or at this datetime (inclusive).
limit	integer	Max statements to return. Default 50, max 500.
ascending	boolean	true = oldest first. Default false (newest first).

http

GET /xapi/statements?agent={"mbox":"mailto:student@school.edu","objectType":"Agent"}&activity=https://your-game.com&limit=20
Authorization: Basic <base64(key:secret)>
X-Experience-API-Version: 1.0.3

// 200 OK:
{
  "statements": [ ...xAPI statement objects... ],
  "more": "/xapi/statements?agent=...&offset=20&limit=20"
}

PUT Submit Statement by ID

Submit a single statement with a specific UUID. The ID is taken from the query string, not the body. Idempotent — if the ID is already stored, the request returns 204 and the stored statement is left unchanged.

http

PUT /xapi/statements?statementId=550e8400-e29b-41d4-a716-446655440000
Authorization: Basic <base64(key:secret)>
Content-Type: application/json
X-Experience-API-Version: 1.0.3

{
  "actor":  { "objectType": "Agent", "mbox": "mailto:student@school.edu" },
  "verb":   { "id": "http://adlnet.gov/expapi/verbs/passed", "display": { "en-US": "passed" } },
  "object": { "objectType": "Activity", "id": "https://your-game.com/quiz-1" },
  "result": { "score": { "raw": 90, "min": 0, "max": 100, "scaled": 0.9 }, "success": true }
}

// 204 No Content — accepted (or ID already stored; existing statement unchanged)
// 429 Too Many Requests — rate limit (120 requests/min per credential)

Statement Object Reference

Field	Required	Description
id	No	UUID. Assigned by LRS if omitted. Include for idempotency.
actor	Yes	Agent or Group who performed the action.
verb	Yes	IRI + display name of the action performed.
object	Yes	Activity, Agent, StatementRef, or SubStatement.
result	No	Score, success, completion, duration, response.
context	No	Registration UUID, instructor, team, parent activities, extensions.
timestamp	No	ISO 8601 datetime the experience occurred. LRS records stored time separately.
authority	No	Set by LRS to the credential used. Not accepted from clients.

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