# @aws-sdk/s3-presigned-post

> [![NPM version](https://img.shields.io/npm/v/@aws-sdk/s3-presigned-post/latest.svg)](https://www.npmjs.com/package/@aws-sdk/s3-presigned-post) [![NPM downloads](https://img.shields.io/npm/dm/@aws-sdk/s3-presigned-post.svg)](https://www.npmjs.com/package/@

Latest version **3.1136.0** (published 2026-09-18) · Apache-2.0 license · 0 weekly downloads

## Install

```sh
npm install @aws-sdk/s3-presigned-post
pnpm add @aws-sdk/s3-presigned-post
yarn add @aws-sdk/s3-presigned-post
bun add @aws-sdk/s3-presigned-post
```

## Health

**Score 70/100 (B)** — status: active.

Positive: has types; esm support; no vulnerabilities; recently updated; high maintenance score; high quality score.

Warnings: low downloads.

## Facts

| | |
|---|---|
| Version | 3.1136.0 |
| Published | 2026-09-18 |
| First published | 2020-10-31 |
| Weekly downloads | 0 |
| License | Apache-2.0 |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Node | >=20.0.0 |
| Dependencies | 7 |
| Unpacked size | 26 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 3666 |
| Author | AWS SDK for JavaScript Team |
| Maintainers | amzn-oss, aws-sdk-bot |

## Links

- npm: https://www.npmjs.com/package/@aws-sdk/s3-presigned-post
- Repository: https://github.com/aws/aws-sdk-js-v3
- Homepage: https://github.com/aws/aws-sdk-js-v3/tree/main/packages/s3-presigned-post
- Issues: https://github.com/aws/aws-sdk-js-v3/issues
- npm.io page: https://npm.io/package/@aws-sdk/s3-presigned-post

## Dependencies (7)

- [tslib](https://npm.io/package/tslib.md) ^2.6.2
- [@smithy/core](https://npm.io/package/@smithy/core.md) ^3.33.3
- [@aws-sdk/core](https://npm.io/package/@aws-sdk/core.md) ^3.978.0
- [@smithy/types](https://npm.io/package/@smithy/types.md) ^4.17.2
- [@aws-sdk/types](https://npm.io/package/@aws-sdk/types.md) ^3.974.5
- [@aws-sdk/client-s3](https://npm.io/package/@aws-sdk/client-s3.md) 3.1136.0
- [@smithy/signature-v4](https://npm.io/package/@smithy/signature-v4.md) ^5.6.12

## Recent versions

- 3.1136.0 (latest) — 2026-09-18
- 3.5.1-rc.0 (rc) — 2021-02-19
- 3.1135.0 — 2026-09-17
- 3.1134.0 — 2026-09-16
- 3.1133.0 — 2026-09-15
- 3.1132.0 — 2026-09-14
- 3.1131.0 — 2026-09-11
- 3.1130.0 — 2026-09-10
- 3.1129.0 — 2026-09-09
- 3.1128.0 — 2026-09-08
- 3.1127.0 — 2026-09-04
- 3.1126.0 — 2026-09-03
- 3.1125.0 — 2026-09-02
- 3.1124.0 — 2026-09-01
- 3.1123.0 — 2026-08-31
- … 723 more at https://npm.io/package/@aws-sdk/s3-presigned-post/versions

## README

# @aws-sdk/s3-presigned-post

[![NPM version](https://img.shields.io/npm/v/@aws-sdk/s3-presigned-post/latest.svg)](https://www.npmjs.com/package/@aws-sdk/s3-presigned-post)
[![NPM downloads](https://img.shields.io/npm/dm/@aws-sdk/s3-presigned-post.svg)](https://www.npmjs.com/package/@aws-sdk/s3-presigned-post)

This package provide a function generating URL and fields. Users without AWS credentials can use the URL and fields to
to make a POST request to S3. The documentation for the server side feature can be found in [S3 API Reference](https://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-UsingHTTPPOST.html). Please read related sections for more context.

### Import

JavaScript Example:

```javascript
const { createPresignedPost } = require("@aws-sdk/s3-presigned-post");
const { S3Client } = require("@aws-sdk/client-s3");
```

ES6 Example

```javascript
import { createPresignedPost } from "@aws-sdk/s3-presigned-post";
import { S3Client } from "@aws-sdk/client-s3";
```

### Create a POST Policy

You can optionally attach a policy to a presigned post. It specifies a list of conditions that the request must meet.
For example:

```typescript
const Conditions = [
  { acl: "bucket-owner-full-control" },
  { bucket: "johnsmith" },
  ["starts-with", "$key", "user/eric/"],
];
```

Visit [S3 POST documentation](https://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-HTTPPOSTConstructPolicy.html)
for supported policy elements. If you include a condition, you must specify the valid value in the `Fields` parameter
as well. A value will not be added automatically to the fields dictionary according to the conditions.

### Generate a Presigned Post

Users can generate required url and fields for POST request:

```typescript
const client = new S3Client({ region: "us-west-2" });
const Bucket = "johnsmith";
const Key = "user/eric/1";
const Fields = {
  acl: "bucket-owner-full-control",
};
const { url, fields } = await createPresignedPost(client, {
  Bucket,
  Key,
  Conditions,
  Fields,
  Expires: 600, //Seconds before the presigned post expires. 3600 by default.
});
```

The `Bucket`, `Key` and other values in `Fields` must meet the conditions specified in `Conditions`. The `Key` can also
contain `${filename}` that will be automatically replaced by the name of the file provided. See [the S3 reference](https://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-HTTPPOSTForms.html#sigv4-HTTPPOSTFormFields)
for more information.

### Post File using HTML Form

You can also post a file with HTML form:

```html
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  </head>
  <body>
    <!-- Copy the 'url' value returned by createPresignedPost() -->
    <form action="URL_VALUE" method="post" enctype="multipart/form-data">
      <!-- Copy the 'fields' key:values returned by S3Client.generate_presigned_post() -->
      <input type="hidden" name="key" value="VALUE" />
      <input type="hidden" name="AWSAccessKeyId" value="VALUE" />
      <input type="hidden" name="policy" value="VALUE" />
      <input type="hidden" name="signature" value="VALUE" />
      File:
      <input type="file" name="file" /> <br />
      <input type="submit" name="submit" value="Upload to Amazon S3" />
    </form>
  </body>
</html>
```

### Post File using FormData in Node.js

In Node.js, use `form-data` package to post a file:

```typescript
const { createReadStream } = require("fs");
const FormData = require("form-data");

const form = new FormData();
Object.entries(fields).forEach(([field, value]) => {
  form.append(field, value);
});
form.append("file", createReadStream("path/to/a/file"));
form.submit(url, (err, res) => {
  //handle the response
});
```

---
_Source: https://npm.io/package/@aws-sdk/s3-presigned-post · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._