Upload a file.

curl -X POST "https://api.mattermode.com/v1/files" \  -F file="string" \  -F purpose="kyc_document"

const body = new FormData();body.set(file, "string")body.set(purpose, "kyc_document")fetch("https://api.mattermode.com/v1/files", {  method: "POST",  headers: {    "Content-Type": "multipart/form-data"  },  body})

package mainimport (  "fmt"  "net/http"  "io/ioutil"  "mime/multipart"  "bytes")func main() {  url := "https://api.mattermode.com/v1/files"  body := new(bytes.Buffer)  mp := multipart.NewWriter(payload)  mp.WriteField("file", `string`)  mp.WriteField("purpose", `kyc_document`)  req, _ := http.NewRequest("POST", url, body)  req.Header.Add("Content-Type", "multipart/form-data")  res, _ := http.DefaultClient.Do(req)  defer res.Body.Close()  body, _ := ioutil.ReadAll(res.Body)  fmt.Println(res)  fmt.Println(string(body))}

import requestsheaders = {    "Authorization": "Bearer sk_test_4eC39HqLyjWDarjtT1zdp7dc",    "Matter-Version": "2026-06-10",    "Idempotency-Key": "ee7c3a9b-3f1a-4d8e-9b2a-7c5e1f0a2d4b",}resp = requests.post(    "https://api.mattermode.com/v1/files",    headers=headers,)resp.raise_for_status()print(resp.json())

import java.net.URI;import java.net.http.HttpClient;import java.net.http.HttpRequest;import java.net.http.HttpResponse;import java.net.http.HttpResponse.BodyHandlers;import java.time.Duration;import java.net.http.HttpRequest.BodyPublishers;var body = BodyPublishers.ofByteArray(new byte[] { ... });HttpClient client = HttpClient.newBuilder()  .connectTimeout(Duration.ofSeconds(10))  .build();HttpRequest.Builder requestBuilder = HttpRequest.newBuilder()  .uri(URI.create("https://api.mattermode.com/v1/files"))  .header("Content-Type", "multipart/form-data")  .POST(body)  .build();try {  HttpResponse<String> response = client.send(requestBuilder.build(), BodyHandlers.ofString());  System.out.println("Status code: " + response.statusCode());  System.out.println("Response body: " + response.body());} catch (Exception e) {  e.printStackTrace();}

using System;using System.Net.Http;using System.Text;var body = new MultipartFormDataContent();var client = new HttpClient();var response = await client.PostAsync("https://api.mattermode.com/v1/files", body);var responseBody = await response.Content.ReadAsStringAsync();

curl --request POST 'https://api.mattermode.com/v1/files' \  --header 'Authorization: Bearer sk_test_4eC39HqLyjWDarjtT1zdp7dc' \  --header 'Matter-Version: 2026-06-10' \  --header 'Idempotency-Key: ee7c3a9b-3f1a-4d8e-9b2a-7c5e1f0a2d4b'

const response = await fetch("https://api.mattermode.com/v1/files", {  method: "POST",  headers: {    "Authorization": "Bearer sk_test_4eC39HqLyjWDarjtT1zdp7dc",    "Matter-Version": "2026-06-10",    "Idempotency-Key": "ee7c3a9b-3f1a-4d8e-9b2a-7c5e1f0a2d4b",  },});if (!response.ok) {  throw new Error(`Matter API ${response.status}: ${await response.text()}`);}const data = await response.json();console.log(data);