We are a Swiss Army knife for your files
Transloadit is a service for companies with developers. We handle their file uploads and media processing. This means that they can save on development time and the heavy machinery that is required to handle big volumes in an automated way.
We pioneered with this concept in 2009 and have made our customers happy ever since. We are still actively improving our service in 2026, as well as our open source projects uppy.io and tus.io, which are changing how the world does file uploading.
Fade in and out audio file
Using custom FFmpeg parameters Transloadit can encode your media files in a variety of ways. In this demo, we are going to show how using our API you can trim an audio file, have it fade-in at the beginning, and fade-out at the end.
When encoding media files of any kind, it is always important to have full control of your operation
so that you can get exactly what you are looking for. Luckily, we have just the tool we need to
encode our audio files to perfection. Using our ffmpeg parameter we have numerous encoding options
to our disposal. Let's break down what each ffmpeg parameter is doing.
Using FFMpeg's af parameter, we can do some pretty neat things when encoding audio files. When we
combine it with the afade parameter we can set fade-in and fade-out options. We use its embedded
st parameter to select where the fade effect starts, and to determine how long the fade effect
lasts till volume is back to normal we use the d parameter.
The second FFMpeg parameter we use is the to parameter. This allows us to trim our file to the
length we want by setting the duration of our file.
:bulb: combining the ss parameter with the to parameter, allows you to specify a clip from an
audio file to be extracted, as shown in this
demo. However, we will not be
needing that today as we want our fade-in effect to start right at the beginning of our file.
Along with these parameters we also use our mp3 preset.
Step 1:
Handle uploads
We can handle uploads of your users directly.Learn more
":original": {
"robot": "/upload/handle"
}Step 2:
Encode audio
We offer a variety of features to reduce audio size while maintaining quality, as well as add effects like loops or watermarks.Learn more
"encode_audio": {
"use": ":original",
"robot": "/audio/encode",
"result": true,
"ffmpeg": {
"af": "afade=t=in:st=0:d=4, afade=t=out:st=13:d=3",
"to": "16"
},
"ffmpeg_stack": "v7",
"preset": "mp3"
}Step 3:
Export files to Amazon S3
We export to the storage platform of your choice.Learn more
"exported": {
"use": [
"encode_audio",
":original"
],
"robot": "/s3/store",
"credentials": "demo_s3_credentials",
"url_prefix": "https://demos.transloadit.com/"
}Live Demo. See for yourself
Loading Uppy demo…
This live demo is powered by 
Uppy, our open source file uploader that you can also use without Transloadit, and 
tus, our open protocol for resumable file uploads that is making uploading more reliable across the world.
Build this in your own language
<!-- This pulls Uppy from our CDN -->
<!-- For smaller self-hosted bundles, install Uppy and plugins manually: -->
<!-- npm i --save @uppy/core @uppy/dashboard @uppy/remote-sources @uppy/transloadit ... -->
<link
href="https://releases.transloadit.com/uppy/v3.10.0/uppy.min.css"
rel="stylesheet"
/>
<button id="browse">Select Files</button>
<script type="module">
import {
Uppy,
Dashboard,
ImageEditor,
RemoteSources,
Transloadit,
} from 'https://releases.transloadit.com/uppy/v3.10.0/uppy.min.mjs'
const uppy = new Uppy()
.use(Transloadit, {
waitForEncoding: true,
alwaysRunAssembly: true,
assemblyOptions: {
params: {
// It's often better store encoding instructions in your account
// and use a `template_id` instead of adding these steps inline
steps: {
':original': {
robot: '/upload/handle',
},
encode_audio: {
use: ':original',
robot: '/audio/encode',
result: true,
ffmpeg: {
af: 'afade=t=in:st=0:d=4, afade=t=out:st=13:d=3',
to: '16',
},
ffmpeg_stack: 'v7',
preset: 'mp3',
},
exported: {
use: ['encode_audio', ':original'],
robot: '/s3/store',
credentials: 'demo_s3_credentials',
url_prefix: 'https://demos.transloadit.com/',
},
},
},
},
})
.use(Dashboard, { trigger: '#browse' })
.use(ImageEditor, { target: Dashboard })
.use(RemoteSources, {
companionUrl: 'https://api2.transloadit.com/companion',
})
.on('complete', ({ transloadit }) => {
// Due to `waitForEncoding:true` this is fired after encoding is done.
// Alternatively, set `waitForEncoding` to `false` and provide a `notify_url`
console.log(transloadit) // Array of Assembly Statuses
for (const assembly of transloadit) {
console.log(assembly.results) // Array of all encoding results
}
})
.on('error', (error) => {
console.error(error)
})
</script>
So many ways to integrate
Transloadit is a service for companies with developers. And there are many ways developers can put Transloadit to good use inside your company to automate media processing.
Bulk imports
Add one of our import Robots to acquire and transcode massive media libraries.
Handling uploads
We are the experts at reliably handling uploads. We wrote the protocol for it.
Front-end integration
We integrate with web browsers via our next-gen file uploader Uppy and SDKs for Android and iOS.
Back-end integration
Send us batch jobs in any server language using one of our SDKs or directly interfacing with our REST API.
Pingbacks
Configure a notify_url to let your server receive transcoding results JSON in the transloadit POST field.
On-demand
Use our Smart CDN to adapt files on-demand and stream them directly to your users.
Audio encoding
Document processing