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Good to know
The Memocard object
List the memocards of a content
Create a memocard
Retrieve a memocard
Update a memocard
Delete a memocard

A memocard is a notion to remember: a front (the question) and a back (the answer), reviewed with spaced repetition in the app. Memocards belong to a content and are listed in its order.

Good to know

The back is written and read as text; LaTeX formulas are kept.
retention and lastReviewedAt describe how well the account the key acts for remembers the memocard; they are filled in lists (GET …/memocards).
A memocard shared through a space can be read; only its owner updates or deletes it. Deleting a memocard deletes its questions.
To generate a content’s memocards with AI, see AI generations.

The Memocard object

A memocard (flashcard): a front, a back, reviewed with spaced repetition.

Field	Type	Description
`id`always present	`string (uuid)`	Memocard identifier (UUID).
`contentId`always present	`string \| null`	Content the memocard belongs to.
`front`always present	`string \| null`	Front side: the prompt or title.
`back`always present	`string \| null`	Back side, as plain text (formulas between $…$ , `$$…$$`).
`explanation`always present	`string \| null`	Optional explanation, or null.
`retention`always present	`number \| null`from 0 to 1	Estimated retention for the account (0 to 1, spaced-repetition model), given in lists; null when never reviewed or on a single read.
`lastReviewedAt`always present	`string (date-time) \| null`	Last review by the account, given in lists; null when never reviewed or on a single read.
`createdAt`always present	`string (date-time) \| null`	Creation instant (ISO 8601, UTC).
`updatedAt`always present	`string (date-time) \| null`	Last update instant (ISO 8601, UTC).

Memocard

{
  "id": "c5e8a1b2-3d4f-4a6b-9c8d-7e6f5a4b3c21",
  "contentId": "3f1c2b0e-8d4a-4f7e-9a51-3c2d1e0f9b87",
  "front": "Where does photosynthesis take place?",
  "back": "In the chloroplasts, mainly in the leaves.",
  "explanation": null,
  "retention": 0.82,
  "lastReviewedAt": "2026-10-03T18:12:00.000Z",
  "createdAt": "2026-10-01T14:05:00.000Z",
  "updatedAt": "2026-10-01T14:05:00.000Z"
}

List the memocards of a content

GET/v1/contents/{contentId}/memocardsScope memocards:read

Memocards of the content, in its order, paginated. retention and lastReviewedAt are those of the account the key acts for.

Parameters

Field	In	Type	Description
`contentId`required	path	`string (uuid)`	Content identifier (UUID).
`limit`optional	query	`integer`from 1 to 100 · default 20	Number of items per page, 1 to 100 (default 20).
`cursor`optional	query	`string`at most 200 characters	Opaque cursor: the `nextCursor` of the previous page. Keep the same `limit` from one page to the next.

Response 200

A page of memocards — A page of Memocard { data, nextCursor, hasMore }

Errors

HTTP	Meaning
`400`	`validation_error` or `invalid_cursor`
`401`	`invalid_api_key` or `revoked_api_key`
`403`	`insufficient_scope`, `account_suspended`, `live_not_enabled` or `forbidden`
`404`	`not_found` — the content does not exist or is not visible to this key
`406`	`not_acceptable` — the `Accept` header excludes `application/json`
`429`	`rate_limited` or `test_quota_exceeded` — see the `Retry-After` and `RateLimit-*` headers
`500`	`internal_error`
`503`	`unavailable` — see the `Retry-After` header

Request

curl "https://api.memojin.com/v1/contents/3f1c2b0e-8d4a-4f7e-9a51-3c2d1e0f9b87/memocards?limit=20" \
  -H "Authorization: Bearer $MEMOJIN_API_KEY"

Response 200

{
  "data": [
    {
      "id": "c5e8a1b2-3d4f-4a6b-9c8d-7e6f5a4b3c21",
      "contentId": "3f1c2b0e-8d4a-4f7e-9a51-3c2d1e0f9b87",
      "front": "Where does photosynthesis take place?",
      "back": "In the chloroplasts, mainly in the leaves.",
      "explanation": null,
      "retention": 0.82,
      "lastReviewedAt": "2026-10-03T18:12:00.000Z",
      "createdAt": "2026-10-01T14:05:00.000Z",
      "updatedAt": "2026-10-01T14:05:00.000Z"
    }
  ],
  "nextCursor": null,
  "hasMore": false
}

Create a memocard

POST/v1/contents/{contentId}/memocardsScope memocards:write

Adds a memocard at the end of the content. Answers 201 with the memocard and its Location.

Parameters

Field	In	Type	Description
`contentId`required	path	`string (uuid)`	Content identifier (UUID).
`Idempotency-Key`optional	header	`string`	Strongly recommended. A unique value per operation (UUID v4), reused unchanged on every retry. Within 24 hours, the same key and the same request replay the first response (`Idempotent-Replayed: true`) without a second effect or charge; another request with the same key → 422 `idempotency_key_reused`; still running → 409 `idempotency_in_progress`.

Request body `CreateMemocardRequest`

A new memocard.

Field	Type	Description
`front`required	`string`1 to 2000 characters	Front side (1 to 2,000 characters).
`back`required	`string`1 to 20000 characters	Back side, plain text (formulas between $…$ ).
`explanation`optional	`string \| null`at most 5000 characters	Optional explanation.

Response 201

The memocard created — A Memocard object

Errors

HTTP	Meaning
`400`	`validation_error` or `bad_request`
`401`	`invalid_api_key` or `revoked_api_key`
`403`	`insufficient_scope`, `account_suspended`, `live_not_enabled` or `forbidden`
`404`	`not_found` — the content does not exist or is not visible to this key
`406`	`not_acceptable` — the `Accept` header excludes `application/json`
`409`	`idempotency_in_progress` — retry after `Retry-After` (1 s)
`413`	`payload_too_large`
`415`	`unsupported_media_type`
`422`	`idempotency_key_reused`, or a business rule (see the description)
`429`	`rate_limited` or `test_quota_exceeded` — see the `Retry-After` and `RateLimit-*` headers
`500`	`internal_error`
`503`	`unavailable` — see the `Retry-After` header

Request

curl -X POST "https://api.memojin.com/v1/contents/3f1c2b0e-8d4a-4f7e-9a51-3c2d1e0f9b87/memocards" \
  -H "Authorization: Bearer $MEMOJIN_API_KEY" \
  -H "Idempotency-Key: 6f1c2b0e-8d4a-4f7e-9a51-3c2d1e0f9b87" \
  -H "Content-Type: application/json" \
  -d '{
  "front": "Where does photosynthesis take place?",
  "back": "In the chloroplasts, mainly in the leaves."
}'

Response 201

{
  "id": "c5e8a1b2-3d4f-4a6b-9c8d-7e6f5a4b3c21",
  "contentId": "3f1c2b0e-8d4a-4f7e-9a51-3c2d1e0f9b87",
  "front": "Where does photosynthesis take place?",
  "back": "In the chloroplasts, mainly in the leaves.",
  "explanation": null,
  "retention": 0.82,
  "lastReviewedAt": "2026-10-03T18:12:00.000Z",
  "createdAt": "2026-10-01T14:05:00.000Z",
  "updatedAt": "2026-10-01T14:05:00.000Z"
}

Retrieve a memocard

GET/v1/memocards/{memocardId}Scope memocards:read

One memocard visible to the account the API key acts for (its own, or shared with it through a space). Answers 304 to a matching If-None-Match.

Parameters

Field	In	Type	Description
`memocardId`required	path	`string (uuid)`	Memocard identifier (UUID).

Response 200

The memocard — A Memocard object

Errors

HTTP	Meaning
`400`	`validation_error` — an identifier is not a UUID
`401`	`invalid_api_key` or `revoked_api_key`
`403`	`insufficient_scope`, `account_suspended`, `live_not_enabled` or `forbidden`
`404`	`not_found`
`406`	`not_acceptable` — the `Accept` header excludes `application/json`
`429`	`rate_limited` or `test_quota_exceeded` — see the `Retry-After` and `RateLimit-*` headers
`500`	`internal_error`
`503`	`unavailable` — see the `Retry-After` header

Request

curl "https://api.memojin.com/v1/memocards/c5e8a1b2-3d4f-4a6b-9c8d-7e6f5a4b3c21" \
  -H "Authorization: Bearer $MEMOJIN_API_KEY"

Response 200

{
  "id": "c5e8a1b2-3d4f-4a6b-9c8d-7e6f5a4b3c21",
  "contentId": "3f1c2b0e-8d4a-4f7e-9a51-3c2d1e0f9b87",
  "front": "Where does photosynthesis take place?",
  "back": "In the chloroplasts, mainly in the leaves.",
  "explanation": null,
  "retention": 0.82,
  "lastReviewedAt": "2026-10-03T18:12:00.000Z",
  "createdAt": "2026-10-01T14:05:00.000Z",
  "updatedAt": "2026-10-01T14:05:00.000Z"
}

Update a memocard

PATCH/v1/memocards/{memocardId}Scope memocards:write

Changes the front, the back or the explanation. Owner only.

Parameters

Field	In	Type	Description
`memocardId`required	path	`string (uuid)`	Memocard identifier (UUID).

Request body `UpdateMemocardRequest`

The fields to change; the others stay as they are.

Field	Type	Description
`front`optional	`string`1 to 2000 characters	New front side.
`back`optional	`string`1 to 20000 characters	New back side, plain text.
`explanation`optional	`string \| null`at most 5000 characters	New explanation, or null to clear it.

Response 200

The memocard updated — A Memocard object

Errors

HTTP	Meaning
`400`	`validation_error` or `bad_request`
`401`	`invalid_api_key` or `revoked_api_key`
`403`	`insufficient_scope`, `account_suspended`, `live_not_enabled` or `forbidden`
`404`	`not_found`
`406`	`not_acceptable` — the `Accept` header excludes `application/json`
`412`	`precondition_failed` — `If-Match` does not match the current `ETag`
`413`	`payload_too_large`
`415`	`unsupported_media_type`
`429`	`rate_limited` or `test_quota_exceeded` — see the `Retry-After` and `RateLimit-*` headers
`500`	`internal_error`
`503`	`unavailable` — see the `Retry-After` header

Request

curl -X PATCH "https://api.memojin.com/v1/memocards/c5e8a1b2-3d4f-4a6b-9c8d-7e6f5a4b3c21" \
  -H "Authorization: Bearer $MEMOJIN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "back": "In the chloroplasts."
}'

Response 200

{
  "id": "c5e8a1b2-3d4f-4a6b-9c8d-7e6f5a4b3c21",
  "contentId": "3f1c2b0e-8d4a-4f7e-9a51-3c2d1e0f9b87",
  "front": "Where does photosynthesis take place?",
  "back": "In the chloroplasts, mainly in the leaves.",
  "explanation": null,
  "retention": 0.82,
  "lastReviewedAt": "2026-10-03T18:12:00.000Z",
  "createdAt": "2026-10-01T14:05:00.000Z",
  "updatedAt": "2026-10-01T14:05:00.000Z"
}

Delete a memocard

DELETE/v1/memocards/{memocardId}Scope memocards:write

Deletes the memocard and its questions. Owner only. Answers 204 without a body.

Parameters

Field	In	Type	Description
`memocardId`required	path	`string (uuid)`	Memocard identifier (UUID).

Response 204

Deleted — No response body.

Errors

HTTP	Meaning
`400`	`validation_error` — an identifier is not a UUID
`401`	`invalid_api_key` or `revoked_api_key`
`403`	`insufficient_scope`, `account_suspended`, `live_not_enabled` or `forbidden`
`404`	`not_found`
`406`	`not_acceptable` — the `Accept` header excludes `application/json`
`412`	`precondition_failed` — `If-Match` does not match the current `ETag`
`429`	`rate_limited` or `test_quota_exceeded` — see the `Retry-After` and `RateLimit-*` headers
`500`	`internal_error`
`503`	`unavailable` — see the `Retry-After` header

Request

curl -X DELETE "https://api.memojin.com/v1/memocards/c5e8a1b2-3d4f-4a6b-9c8d-7e6f5a4b3c21" \
  -H "Authorization: Bearer $MEMOJIN_API_KEY"

Memojin for

Features

Subjects

Resources

Memocards

Good to know

The Memocard object

List the memocards of a content

Parameters

Response 200

Errors

Create a memocard

Parameters

Request body `CreateMemocardRequest`

Response 201

Errors

Retrieve a memocard

Parameters

Response 200

Errors

Update a memocard

Parameters

Request body `UpdateMemocardRequest`

Response 200

Errors

Delete a memocard

Parameters

Response 204

Errors

Memocards

Good to know

The Memocard object

List the memocards of a content

Parameters

Response 200

Errors

Create a memocard

Parameters

Request body CreateMemocardRequest

Response 201

Errors

Retrieve a memocard

Parameters

Response 200

Errors

Update a memocard

Parameters

Request body UpdateMemocardRequest

Response 200

Errors

Delete a memocard

Parameters

Response 204

Errors

Request body `CreateMemocardRequest`

Request body `UpdateMemocardRequest`