Send and receive files across chat platforms.
Attach files to messages using the files property:
const reportBuffer = Buffer.from("PDF content");
await thread.post({
markdown: "Here's the report you requested:",
files: [
{
data: reportBuffer,
filename: "report.pdf",
mimeType: "application/pdf",
},
],
});Typed attachments
Use attachments when you already have normalized Attachment objects and the adapter supports typed outgoing media. Telegram supports one outgoing attachment per message and uses the native media method for the attachment type:
await thread.post({
markdown: "Here's the image:",
attachments: [
{
data: imageBuffer,
name: "diagram.png",
mimeType: "image/png",
type: "image",
},
],
});Outgoing attachments are available on { raw }, { markdown }, and { ast } messages. Card messages use files for uploads. Use files for generic uploads. On Telegram, files always upload as documents, while attachments preserve image, audio, video, or file media type. Use data or fetchData for private/authenticated files; URL-only attachments must be public URLs Telegram can fetch directly.
Multiple files
await thread.post({
markdown: "Attached are the images:",
files: [
{ data: image1, filename: "screenshot1.png" },
{ data: image2, filename: "screenshot2.png" },
],
});Files without text
await thread.post({
markdown: "",
files: [{ data: buffer, filename: "document.xlsx" }],
});Access attachments from incoming messages:
bot.onSubscribedMessage(async (thread, message) => {
for (const attachment of message.attachments ?? []) {
console.log(`File: ${attachment.name}, Type: ${attachment.mimeType}`);
if (attachment.fetchData) {
const data = await attachment.fetchData();
console.log(`Downloaded ${data.length} bytes`);
}
}
});Attachment properties
| Property | Type | Description |
|---|---|---|
type | string | Attachment type (e.g., "image", "file") |
url | string (optional) | Public URL |
name | string (optional) | Filename |
mimeType | string (optional) | MIME type |
size | number (optional) | File size in bytes |
width | number (optional) | Image width |
height | number (optional) | Image height |
fetchData | () => Promise<Buffer> (optional) | Download the file data |
fetchMetadata | Record<string, string> (optional) | Platform-specific IDs for reconstructing fetchData after serialization |