Upload a File

curl --request POST \
  --url https://api.checkfu.com/v1/files \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --header 'checkfu-version: <checkfu-version>' \
  --form file='@example-file'

import requests

url = "https://api.checkfu.com/v1/files"

files = { "file": ("example-file", open("example-file", "rb")) }
headers = {
    "checkfu-version": "<checkfu-version>",
    "Authorization": "Bearer <token>"
}

response = requests.post(url, files=files, headers=headers)

print(response.text)

const form = new FormData();
form.append('file', '<string>');

const options = {
  method: 'POST',
  headers: {'checkfu-version': '<checkfu-version>', Authorization: 'Bearer <token>'}
};

options.body = form;

fetch('https://api.checkfu.com/v1/files', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.checkfu.com/v1/files",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: multipart/form-data",
    "checkfu-version: <checkfu-version>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.checkfu.com/v1/files"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("checkfu-version", "<checkfu-version>")
	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.checkfu.com/v1/files")
  .header("checkfu-version", "<checkfu-version>")
  .header("Authorization", "Bearer <token>")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.checkfu.com/v1/files")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["checkfu-version"] = '<checkfu-version>'
request["Authorization"] = 'Bearer <token>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--"

response = http.request(request)
puts response.read_body

{
  "id": "<string>",
  "workspace_id": "<string>",
  "filename": "<string>",
  "mime_type": "<string>",
  "size_bytes": 1,
  "sha256": "<string>",
  "created_at": "<string>"
}

{
  "error": {
    "type": "validation.malformed",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-malformed"
  }
}

{
  "error": {
    "type": "auth.invalid_key",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#auth-invalid-key"
  }
}

{
  "error": {
    "type": "auth.disabled_tenancy",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#auth-disabled-tenancy"
  }
}

{
  "error": {
    "type": "validation.not_found",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-not-found"
  }
}

{
  "error": {
    "type": "validation.conflict",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-conflict"
  }
}

{
  "error": {
    "type": "validation.payload_too_large",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-payload-too-large"
  }
}

{
  "error": {
    "type": "budget.exceeded",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#budget-exceeded"
  }
}

{
  "error": {
    "type": "runtime.internal",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#runtime-internal"
  }
}

Upload a File

Upload one multipart/form-data part named file, capped at 64 MiB of content, and receive the immutable File metadata (id, filename, mime_type, size_bytes, sha256, created_at). Filenames are basenames, never mount paths, and the body itself is never readable back through the API. Send Idempotency-Key to make retries safe: exact replay returns the original File, while different input under the same key conflicts. A zero-data-retention workspace rejects creation because a File body is durable content.

Checkfu support posture: alpha; hosted. Required evidence journey: files. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities.

POST

files

Upload a File

curl --request POST \
  --url https://api.checkfu.com/v1/files \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --header 'checkfu-version: <checkfu-version>' \
  --form file='@example-file'

import requests

url = "https://api.checkfu.com/v1/files"

files = { "file": ("example-file", open("example-file", "rb")) }
headers = {
    "checkfu-version": "<checkfu-version>",
    "Authorization": "Bearer <token>"
}

response = requests.post(url, files=files, headers=headers)

print(response.text)

const form = new FormData();
form.append('file', '<string>');

const options = {
  method: 'POST',
  headers: {'checkfu-version': '<checkfu-version>', Authorization: 'Bearer <token>'}
};

options.body = form;

fetch('https://api.checkfu.com/v1/files', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.checkfu.com/v1/files",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: multipart/form-data",
    "checkfu-version: <checkfu-version>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.checkfu.com/v1/files"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("checkfu-version", "<checkfu-version>")
	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.checkfu.com/v1/files")
  .header("checkfu-version", "<checkfu-version>")
  .header("Authorization", "Bearer <token>")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.checkfu.com/v1/files")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["checkfu-version"] = '<checkfu-version>'
request["Authorization"] = 'Bearer <token>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--"

response = http.request(request)
puts response.read_body

{
  "id": "<string>",
  "workspace_id": "<string>",
  "filename": "<string>",
  "mime_type": "<string>",
  "size_bytes": 1,
  "sha256": "<string>",
  "created_at": "<string>"
}

{
  "error": {
    "type": "validation.malformed",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-malformed"
  }
}

{
  "error": {
    "type": "auth.invalid_key",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#auth-invalid-key"
  }
}

{
  "error": {
    "type": "auth.disabled_tenancy",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#auth-disabled-tenancy"
  }
}

{
  "error": {
    "type": "validation.not_found",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-not-found"
  }
}

{
  "error": {
    "type": "validation.conflict",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-conflict"
  }
}

{
  "error": {
    "type": "validation.payload_too_large",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#validation-payload-too-large"
  }
}

{
  "error": {
    "type": "budget.exceeded",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#budget-exceeded"
  }
}

{
  "error": {
    "type": "runtime.internal",
    "message": "<string>",
    "more": "https://docs.checkfu.com/reference/errors#runtime-internal"
  }
}

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Headers

checkfu-version

enum<string>

required

Available options:

2026-08-27

idempotency-key

string

Maximum string length: 255

Body

multipart/form-data

Exactly one file whose Content-Disposition filename is a basename other than . or ...

file

required

Response

Success

string

required

Pattern: ^file_[0-9a-f]{32}$

workspace_id

string

required

Pattern: ^wrkspc_[0-9a-f]{32}$

filename

string

required

Required string length: 1 - 255

Pattern: ^[^/\\\p{Cc}]+$

mime_type

string

required

Required string length: 1 - 255

Pattern: ^[^\p{Cc}]+$

size_bytes

integer

required

Required range: x >= 0

sha256

string

required

Pattern: ^sha256:[0-9a-f]{64}$

created_at

string

required

Developer tools

Canonical tables

Author protocols

Generated HTTP API

Upload a File

Authorizations

Headers

Body

Response