---
title: "Upload customer attachment"
method: POST
path: "/v3/attachments/customers/{customerId}"
tags: ["attachments"]
---

# Upload customer attachment

`POST /v3/attachments/customers/{customerId}`

Upload an attachment for an existing customer. The file size limit is 6 MB.

**Note**: When you upload an attachment, it takes a few minutes for BILL to complete the upload process.

See [Documents and attachments](https://developer.bill.com/docs/documents-attachments) in the Guides section for more information, sample requests, and responses.

## Path parameters

- `customerId` string, required — BILL-generated ID of the customer. The value begins with `0cu`.

## Query parameters

- `name` string, required — File name with extension. For example, to upload a PDF attachment titled `business_details`, set `name` as `business_details.pdf`.

## Headers

- `sessionId` string, nullable — API session ID generated with `/v3/login`
- `devKey` string, nullable — Developer key generated with your BILL developer account

## Response `200`

Upload customer attachment response

- AttachmentResponseDto — Attachments response.
  - `id` string — BILL-generated ID of the attachment. The value begins with `att`.
  - `name` string — Attachment name
  - `createdTime` string, date-time — Created date and time
  - `downloadLink` string — URL for downloading the attachment. Use the URL in a GET request to download the attachment.

## Other responses

- `4XX` — List of errors.
- `5XX` — List of errors.

---

[API](https://skmtc.net/bill/apis/bill-v3-api.md) · [All operations](https://skmtc.net/bill/apis/bill-v3-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/bill/bill-v3-api/revisions/0483350c434e/schema)