> ## Documentation Index > Fetch the complete documentation index at: https://docs.zavu.dev/llms.txt > Use this file to discover all available pages before exploring further. # Write an item > Store a JSON document under a key. Creates the collection if it does not exist — with **no indexes**, which `query` then cannot use. Declare indexes with `POST /v1/memory/collections` first if you need them. This replaces the whole document; it does not merge. Pass `If-Match` with the revision from a previous read to make the write conditional. ## OpenAPI ````yaml /openapi.json put /v1/memory/collections/{collection}/items/{key} openapi: 3.0.3 info: title: Zavu Unified Messaging Layer API version: 0.2.0 description: > Unified multi-channel messaging API for Zavu. Supported channels: - **SMS**: Simple text messages - **WhatsApp**: Rich messaging with media, buttons, lists, CTA URL buttons, location requests, and templates - **Telegram**: Bot messaging with text, media, and interactive elements - **Email**: Transactional emails via Amazon SES Design goals: - Simple `send()` entrypoint for developers - Project-level authentication via Bearer token - Support for all WhatsApp message types (text, image, video, audio, document, sticker, location, contact, buttons, list, cta_url, location_request, reaction, template) - If a non-text message type is sent, WhatsApp channel is used automatically - 24-hour WhatsApp conversation window enforcement - Universal `to` field accepts phone numbers (E.164), email addresses, or numeric chat IDs (Telegram/Instagram/Messenger) servers: - url: https://api.zavu.dev security: - bearerAuth: [] paths: /v1/memory/collections/{collection}/items/{key}: put: tags: - Memory summary: Write an item description: >- Store a JSON document under a key. Creates the collection if it does not exist — with **no indexes**, which `query` then cannot use. Declare indexes with `POST /v1/memory/collections` first if you need them. This replaces the whole document; it does not merge. Pass `If-Match` with the revision from a previous read to make the write conditional. operationId: putMemoryItem parameters: - $ref: '#/components/parameters/MemoryCollectionParam' - $ref: '#/components/parameters/MemoryItemKeyParam' - $ref: '#/components/parameters/MemoryScopeParam' - $ref: '#/components/parameters/MemoryIfMatchParam' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/MemoryItemPutRequest' example: value: status: shipped total: 42.5 responses: '200': description: Existing item replaced. content: application/json: schema: type: object required: - item properties: item: $ref: '#/components/schemas/MemoryItem' '201': description: Item created. content: application/json: schema: type: object required: - item properties: item: $ref: '#/components/schemas/MemoryItem' '400': description: Invalid key, scope, TTL, or `If-Match`. content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Unauthorized. content: application/json: schema: $ref: '#/components/schemas/Error' '409': description: >- `revision_conflict`: the item changed since the revision in `If-Match`. Re-read it and retry. content: application/json: schema: $ref: '#/components/schemas/Error' '413': description: >- `document_too_large`: the serialized value exceeds 200KB. Memory is not a blob store; put media in file storage and keep the URL here. content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: The plan's monthly unit quota is spent. content: application/json: schema: $ref: '#/components/schemas/Error' security: - bearerAuth: [] components: parameters: MemoryCollectionParam: name: collection in: path required: true description: Collection name. schema: type: string MemoryItemKeyParam: name: key in: path required: true description: 'Item key. 1-255 chars from A-Z a-z 0-9 . _ : @ -' schema: type: string MemoryScopeParam: name: scope in: query required: false description: >- Which scope to address: `contact:`, `conversation:`, or omitted for the project scope. Note the asymmetry with `POST /v1/memory` and `POST /v1/memory/search`, which take the scope in the request BODY as `scope` plus `contactId`/`conversationId`. Every other Memory endpoint takes it here. schema: $ref: '#/components/schemas/MemoryScopeQuery' MemoryIfMatchParam: name: If-Match in: header required: false description: >- Make the write conditional on the item's current revision, as returned by a previous read or write (plain `3` or ETag-quoted `"3"`). The write is refused with `409 revision_conflict` if the item moved on in between. Without it, the write always wins and silently overwrites a concurrent one. schema: type: string example: '3' schemas: MemoryItemPutRequest: type: object required: - value properties: value: description: >- The document to store. Any JSON value, max 200KB serialized and 32 levels deep. This is a whole-document write, not a merge: it replaces whatever the key held. ttlSeconds: type: integer description: Overrides the collection's `defaultTtlSeconds` for this item. minimum: 60 maximum: 63072000 MemoryItem: type: object description: One JSON document in a collection. required: - key - rev - createdAt - updatedAt properties: key: type: string example: ORD-12345 value: description: The stored JSON. Any JSON value. example: status: shipped total: 42.5 rev: type: integer description: >- Revision, incremented on every write. Pass it as `If-Match` on a later write to make that write conditional. example: 3 createdAt: type: string format: date-time updatedAt: type: string format: date-time expiresAt: type: string format: date-time Error: type: object required: - code - message properties: code: type: string example: invalid_request message: type: string example: Phone number is invalid details: type: object additionalProperties: true MemoryScopeQuery: type: string description: >- Scope as a query-string value: `contact:`, `conversation:`, the literal `project`, or omitted for project scope. Only the SHAPE of the id is validated, never its existence — the partition already carries your project, so an id that matches nothing simply addresses an empty scope rather than returning 404. example: contact:jd7x2k3m4n5p6q7r8s9t0abc securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT ````