--- title: Sending Messages | API Docs description: How to send text, media, and rich messages with the Linq API. --- The Linq API lets you send messages containing text, media, or a mix of both across iMessage, RCS, and SMS. ## Starting a conversation To message a new recipient, create a chat with an initial message. The API creates the conversation and sends the message in a single request: - [cURL](#tab-panel-84) - [TypeScript](#tab-panel-85) - [Python](#tab-panel-86) - [Go](#tab-panel-87) Terminal window ``` curl -X POST https://api.linqapp.com/api/partner/v3/chats \ -H "Authorization: Bearer $LINQ_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "from": "+12052535597", "to": [ "+12052532136" ], "message": { "parts": [ { "type": "text", "value": "Hello! How can I help you today?" } ] } }' ``` ``` await client.chats.create({ from: "+12052535597", to: ["+12052532136"], message: { parts: [ { type: "text", value: "Hello! How can I help you today?", }, ], }, }); ``` ``` client.chats.create( from_="+12052535597", to=["+12052532136"], message={ "parts": [ { "type": "text", "value": "Hello! How can I help you today?", }, ], }, ) ``` ``` client.Chats.Create(context.TODO(), linq.ChatNewParams{ From: linq.F("+12052535597"), To: linq.F([]string{"+12052532136"}), Message: linq.F(map[string]any{ Parts: linq.F([]any{ map[string]any{ Type: linq.F("text"), Value: linq.F("Hello! How can I help you today?"), }, }), }), }) ``` A few constraints on this request: - `from` must be a phone number assigned to your account. - `to` accepts an array — one recipient for a direct message, multiple for a [group chat](/guides/chats/group-chats/index.md). - The first outbound message must not contain links. `link` parts and text parts containing URLs are rejected on `POST /v3/chats` — send the initial message without links, then follow up with a [link preview](/guides/messaging/rich-link-previews/index.md) using the returned chat ID. See the [Create Chat](/api/resources/chats/methods/create/index.md) endpoint for the full request schema. ## Sending to an existing chat Once you have a chat ID, post follow-up messages directly to it. The request body is a `message` object with a `parts` array — see the [Send Message API reference](/api/resources/chats/subresources/messages/methods/send/index.md) for the full schema and language-specific examples. ## Message parts Messages use a `parts` array where each part is `text`, `media`, or `link`. You can mix text and media in a single message; link parts must be sent on their own. **Text part:** ``` { "type": "text", "value": "Hello!" } ``` **Media part (direct URL):** ``` { "type": "media", "url": "https://example.com/photo.jpg" } ``` **Media part (pre-uploaded attachment):** ``` { "type": "media", "attachment_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890" } ``` **Link part (rich link preview):** ``` { "type": "link", "value": "https://linqapp.com" } ``` **Mixed message (text + image) — full request body:** ``` { "message": { "parts": [ { "type": "text", "value": "Check out this photo!" }, { "type": "media", "url": "https://example.com/photo.jpg" } ] } } ``` > **Note:** Media parts reference the file by `url` or `attachment_id`. MIME type is inferred server-side — you do not need to pass a `mime_type` field. **Limits:** - Up to **100 parts** per message - Up to **40 public-URL media parts** per message (pre-uploaded attachments are exempt) - Text `value` max length: **10,000** characters - Link `value` (URL) max length: **2,048** characters - Link parts must be the **only** part in a message — they render as a rich preview on iMessage and RCS - Consecutive text parts are **not allowed** — separate them with media or send as individual messages See [Attachments](/guides/messaging/attachments/index.md) for details on sending media files. ## Text decorations Apply inline styles and animations to character ranges within a text part using the `text_decorations` array. Each decoration specifies a `range: [start, end)` (inclusive–exclusive, measured in UTF-16 code units) and exactly one of `style` or `animation`. Decorations are iMessage-only and ignored on RCS and SMS (see [Protocol Selection](/guides/messaging/protocol-selection/index.md)). ``` { "type": "text", "value": "Hello world", "text_decorations": [ { "range": [0, 5], "style": "bold" }, { "range": [6, 11], "animation": "shake" } ] } ``` **Styles:** `bold`, `italic`, `strikethrough`, `underline` **Animations:** `big`, `small`, `shake`, `nod`, `explode`, `ripple`, `bloom`, `jitter` Style ranges may overlap (e.g. bold + italic on the same characters), but animation ranges must not overlap with other animations or styles. ## Replying to messages Thread messages by referencing a specific message ID: - [cURL](#tab-panel-88) - [TypeScript](#tab-panel-89) - [Python](#tab-panel-90) - [Go](#tab-panel-91) Terminal window ``` curl -X POST https://api.linqapp.com/api/partner/v3/chats/{chatId}/messages \ -H "Authorization: Bearer $LINQ_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "message": { "parts": [ { "type": "text", "value": "Great point!" } ], "reply_to": { "message_id": "6ba7b810-9dad-11d1-80b4-00c04fd430c8", "part_index": 0 } } }' ``` ``` await client.chats.messages.send({chatId}, { message: { parts: [ { type: "text", value: "Great point!", }, ], reply_to: { message_id: "6ba7b810-9dad-11d1-80b4-00c04fd430c8", part_index: 0, }, }, }); ``` ``` client.chats.messages.send( {chat_id}, message={ "parts": [ { "type": "text", "value": "Great point!", }, ], "reply_to": { "message_id": "6ba7b810-9dad-11d1-80b4-00c04fd430c8", "part_index": 0, }, }, ) ``` ``` client.Chats.Messages.Send(context.TODO(), {chatId}, linq.ChatMessageSendParams{ Message: linq.F(map[string]any{ Parts: linq.F([]any{ map[string]any{ Type: linq.F("text"), Value: linq.F("Great point!"), }, }), ReplyTo: linq.F(map[string]any{ MessageId: linq.F("6ba7b810-9dad-11d1-80b4-00c04fd430c8"), PartIndex: linq.F(0), }), }), }) ``` The `part_index` field is optional — use it to reply to a specific part of a multipart message (0-indexed). To walk a thread after building it, see [Message Details → Get thread messages](/guides/messaging/message-details#get-thread-messages/index.md). ## Message effects Add iMessage screen or bubble effects (confetti, fireworks, slam, invisible ink, etc.) by including an `effect` object inside `message`. iMessage only — silently ignored on RCS and SMS. See [Message Effects](/guides/messaging/message-effects/index.md) for the full list and an example. ## Protocol selection Force a specific delivery protocol with `preferred_service` (`iMessage`, `RCS`, or `SMS`) inside `message`. If omitted, the API picks the best available. See [Protocol Selection](/guides/messaging/protocol-selection/index.md) for behavior and tradeoffs. ## Idempotency Include an `idempotency_key` field inside the `message` object to prevent duplicate sends on retries. It goes inside the `message` body, not as an HTTP header. Maximum length is 255 characters. - [cURL](#tab-panel-92) - [TypeScript](#tab-panel-93) - [Python](#tab-panel-94) - [Go](#tab-panel-95) Terminal window ``` curl -X POST https://api.linqapp.com/api/partner/v3/chats/{chatId}/messages \ -H "Authorization: Bearer $LINQ_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "message": { "parts": [ { "type": "text", "value": "This won't be sent twice" } ], "idempotency_key": "unique-request-id-123" } }' ``` ``` await client.chats.messages.send({chatId}, { message: { parts: [ { type: "text", value: "This won't be sent twice", }, ], idempotency_key: "unique-request-id-123", }, }); ``` ``` client.chats.messages.send( {chat_id}, message={ "parts": [ { "type": "text", "value": "This won't be sent twice", }, ], "idempotency_key": "unique-request-id-123", }, ) ``` ``` client.Chats.Messages.Send(context.TODO(), {chatId}, linq.ChatMessageSendParams{ Message: linq.F(map[string]any{ Parts: linq.F([]any{ map[string]any{ Type: linq.F("text"), Value: linq.F("This won't be sent twice"), }, }), IdempotencyKey: linq.F("unique-request-id-123"), }), }) ``` The same applies when creating a chat (`POST /v3/chats`) — the key goes inside the nested `message` object: ``` { "from": "+12223334444", "to": ["+15556667777"], "message": { "parts": [{ "type": "text", "value": "Hello" }], "idempotency_key": "unique-request-id-123" } } ``` If a message with the same key has already been processed, the API returns the original response instead of sending again. > **Tip:** Use UUIDs or other globally unique values as idempotency keys, and always set one in production to handle network retries safely. The official [SDKs](/getting-started/sdks/index.md) accept the key via a method option. ## Editing messages Edit a single text part of a previously sent message by passing `part_index` (0-based) and the new `text`. Only text parts are editable. iMessage only — listen for the [`message.edited`](/guides/webhooks/events#message-events/index.md) webhook to confirm the edit was applied. Editable up to **5 times** within **15 minutes** of the original send. See the [Edit Message API reference](/api/resources/messages/methods/update/index.md). ## Deleting messages Delete removes a message from Linq’s records but does **not** unsend it — recipients still see the message on their device. See the [Delete Message API reference](/api/resources/messages/methods/delete/index.md).