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 2024, as well as our open source projects uppy.io and tus.io, which are changing how the world does file uploading.

×

Concatenate two audio files

Transloadit allows you to concatenate multiple audio files together. This is useful when you want to add an intro or an advertisement to the beginning or end of an audio file.

In this particular demo, you can upload the original and we will "pre-roll" a track that we import over HTTP. Audio files are concatenated in the order of the as parameter. For example, audio_1 will be prepended to audio_2, using a natural sorting algorithm.

⚠️ It seems your browser does not send the referer, which we need to stop people from (ab)using our demos in other websites. If you want to use the demos, please allow your browser to send its referer to us. Adding us to the allowlist of blockers usually helps.

Step 1: Handle uploads

We can handle uploads of your users directly. Learn more ›

⚠️ It seems your browser does not support the codec used in this video of the page. For demo simplicity we'll link you to the original file, but you may also want to learn how to make videos compatible for all browsers.
Audio artwork Audio waveform
dutch-anthem.mp3
MP3 audio – 911 KB
58s
":original": {
  "robot": "/upload/handle"
}
🤖/upload/handle
This bot receives uploads that your users throw at you from browser or apps, or that you throw at us programmatically

Step 2: Import files from web servers

We are happy to import from whatever storage solution suits you best. Learn more ›

⚠️ It seems your browser does not support the codec used in this video of the page. For demo simplicity we'll link you to the original file, but you may also want to learn how to make videos compatible for all browsers.
Audio artwork Audio waveform
german-anthem-0.mp3
MP3 audio – 1.2 MB
1m18s
"imported_postroll": {
  "robot": "/http/import",
  "url": "https://demos.transloadit.com/inputs/german-anthem.mp3"
}
🤖/http/import
This bot imports any file that is publicly available via a web URL into Transloadit

Step 3: Concatenate 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 ›

⚠️ It seems your browser does not support the codec used in this video of the page. For demo simplicity we'll link you to the original file, but you may also want to learn how to make videos compatible for all browsers.
Audio artwork Audio waveform
dutch-anthem_german-anthem-0.mp3
MP3 audio – 2.1 MB
2m16s
"concatenated": {
  "use": {
    "steps": [
      {
        "name": ":original",
        "fields": "file",
        "as": "audio_1"
      },
      {
        "name": "imported_postroll",
        "as": "audio_2"
      }
    ]
  },
  "robot": "/audio/concat",
  "result": true,
  "ffmpeg_stack": "v6.0.0"
}
🤖/audio/concat
This bot concatenates several audio files together

Step 4: Export files to Amazon S3

We export to the storage platform of your choice. Learn more ›

"exported": {
  "use": [
    "imported_postroll",
    "concatenated",
    ":original"
  ],
  "robot": "/s3/store",
  "credentials": "YOUR_AWS_CREDENTIALS",
  "path": "${unique_prefix}/both-anthems.${file.ext}",
  "url_prefix": "https://demos.transloadit.com/"
}
🤖/s3/store
This bot exports encoding results to Amazon S3
Since this is a store Robot, be sure to use Template Credentials so that any sensitive data is encrypted and stored in our database, making sure that they’re never exposed to any end-user.

Live Demo. See for yourself

This live demo is powered by Uppy, our open source file uploader that you can also use without Transloadit, andtus, our open protocol for resumable file uploads that is making uploading more reliable across the world.

Build this in your own language

{
  "steps": {
    ":original": {
      "robot": "/upload/handle"
    },
    "imported_postroll": {
      "robot": "/http/import",
      "url": "https://demos.transloadit.com/inputs/german-anthem.mp3"
    },
    "concatenated": {
      "use": {
        "steps": [
          {
            "name": ":original",
            "fields": "file",
            "as": "audio_1"
          }, 
,          {
            "name": "imported_postroll",
            "as": "audio_2"
          }
        ]
      },
      "robot": "/audio/concat",
      "result": true,
      "ffmpeg_stack": "v6.0.0"
    },
    "exported": {
      "use": ["imported_postroll", "concatenated", ":original"],
      "robot": "/s3/store",
      "credentials": "YOUR_AWS_CREDENTIALS",
      "path": "${unique_prefix}/both-anthems.${file.ext}",
      "url_prefix": "https://demos.transloadit.com/"
    }
  }
}
# Prerequisites: brew install curl jq || sudo apt install curl jq
# To avoid tampering, use Signature Authentication
echo '{
  "template_id": undefined,
  "auth": {
    "key": "YOUR_TRANSLOADIT_KEY"
  },
  "steps": {
    ":original": {
      "robot": "/upload/handle"
    },
    "imported_postroll": {
      "robot": "/http/import",
      "url": "https://demos.transloadit.com/inputs/german-anthem.mp3"
    },
    "concatenated": {
      "use": {
        "steps": [
          {
            "name": ":original",
            "fields": "file",
            "as": "audio_1"
          }, 
,          {
            "name": "imported_postroll",
            "as": "audio_2"
          }
        ]
      },
      "robot": "/audio/concat",
      "result": true,
      "ffmpeg_stack": "v6.0.0"
    },
    "exported": {
      "use": ["imported_postroll", "concatenated", ":original"],
      "robot": "/s3/store",
      "credentials": "YOUR_AWS_CREDENTIALS",
      "path": "${unique_prefix}/both-anthems.${file.ext}",
      "url_prefix": "https://demos.transloadit.com/"
    }
  }
}' | curl \\
    --request POST \\
    --form 'params=<-' \\
    --form myfile1=@./dutch-anthem.mp3 \\
    https://api2.transloadit.com/assemblies | jq
// Install via Swift Package Manager:
// dependencies: [
//   .package(url: "https://github.com/transloadit/TransloaditKit", .upToNextMajor(from: "3.0.0"))
// ]

// Or via CocoaPods:
// pod 'Transloadit', '~> 3.0.0'

// Auth
let credentials = Credentials(key: "YOUR_TRANSLOADIT_KEY")

// Init
let transloadit = Transloadit(credentials: credentials, session: "URLSession.shared")

// Add files to upload
let filesToUpload: [URL] = ...

// Execute
let assembly = transloadit.assembly(steps: [_originalStep, imported_postrollStep, concatenatedStep, exportedStep], andUpload: filesToUpload) { result in
  switch result {
  case .success(let assembly):
    print("Retrieved (assembly)")
  case .failure(let error):
    print("Assembly error (error)")
  }
}.pollAssemblyStatus { result in
  switch result {
  case .success(let assemblyStatus):
    print("Received assemblystatus (assemblyStatus)")
  case .failure(let error):
    print("Caught polling error (error)")
  }
<!-- 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/v4.2.0/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/v4.2.0/uppy.min.mjs'
  const uppy = new Uppy()
    .use(Transloadit, {
      waitForEncoding: true,
      alwaysRunAssembly: true,
      assemblyOptions: {
        params: {
          // To avoid tampering, use Signature Authentication:
          // https://transloadit.com/docs/topics/signature-authentication/
          auth: {
            key: 'YOUR_TRANSLOADIT_KEY',
          },
          // 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',
            },
            imported_postroll: {
              robot: '/http/import',
              url: 'https://demos.transloadit.com/inputs/german-anthem.mp3',
            },
            concatenated: {
              use: {
                steps: [
                  {
                    name: ':original',
                    fields: 'file',
                    as: 'audio_1',
                  }, 
,                  {
                    name: 'imported_postroll',
                    as: 'audio_2',
                  }, 
                ],
              },
              robot: '/audio/concat',
              result: true,
              ffmpeg_stack: 'v6.0.0',
            },
            exported: {
              use: ['imported_postroll', 'concatenated', ':original'],
              robot: '/s3/store',
              credentials: 'YOUR_AWS_CREDENTIALS',
              path: '${unique_prefix}/both-anthems.${file.ext}',
              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
      transloadit.forEach((assembly) => {
        console.log(assembly.results) // Array of all encoding results
      })
    })
    .on('error', (error) => {
      console.error(error)
    })
</script>
// yarn add transloadit || npm i transloadit

// Import
const Transloadit = require('transloadit')

const main = async () => {
  // Init
  const transloadit = new Transloadit({
    authKey: 'YOUR_TRANSLOADIT_KEY',
    authSecret: 'MY_TRANSLOADIT_SECRET',
  })

  // Set Encoding Instructions
  const options = {
    files: {
      myfile_1: './dutch-anthem.mp3',
    },
    params: {
      steps: {
        ':original': {
          robot: '/upload/handle',
        },
        imported_postroll: {
          robot: '/http/import',
          url: 'https://demos.transloadit.com/inputs/german-anthem.mp3',
        },
        concatenated: {
          use: {
            steps: [
              {
                name: ':original',
                fields: 'file',
                as: 'audio_1',
              }, 
,              {
                name: 'imported_postroll',
                as: 'audio_2',
              }, 
            ],
          },
          robot: '/audio/concat',
          result: true,
          ffmpeg_stack: 'v6.0.0',
        },
        exported: {
          use: ['imported_postroll', 'concatenated', ':original'],
          robot: '/s3/store',
          credentials: 'YOUR_AWS_CREDENTIALS',
          path: '${unique_prefix}/both-anthems.${file.ext}',
          url_prefix: 'https://demos.transloadit.com/',
        },
      },
    },
  }

  // Execute
  const result = await transloadit.createAssembly(options)

  // Show results
  console.log({ result })
}

main().catch(console.error)
# [sudo] npm install transloadify -g

# Auth
export TRANSLOADIT_KEY="YOUR_TRANSLOADIT_KEY"

# Save Encoding Instructions
echo '{
  "steps": {
    ":original": {
      "robot": "/upload/handle"
    },
    "imported_postroll": {
      "robot": "/http/import",
      "url": "https://demos.transloadit.com/inputs/german-anthem.mp3"
    },
    "concatenated": {
      "use": {
        "steps": [
          {
            "name": ":original",
            "fields": "file",
            "as": "audio_1"
          }, 
,          {
            "name": "imported_postroll",
            "as": "audio_2"
          }
        ]
      },
      "robot": "/audio/concat",
      "result": true,
      "ffmpeg_stack": "v6.0.0"
    },
    "exported": {
      "use": ["imported_postroll", "concatenated", ":original"],
      "robot": "/s3/store",
      "credentials": "YOUR_AWS_CREDENTIALS",
      "path": "${unique_prefix}/both-anthems.${file.ext}",
      "url_prefix": "https://demos.transloadit.com/"
    }
  }
}' > ./steps.json

# Execute
transloadify \
  --input "dutch-anthem.mp3" \
  --steps "./steps.json" \
  --output "./output.example"
// composer require transloadit/php-sdk
use transloadit\Transloadit;

$transloadit = new Transloadit([
  "key" => "YOUR_TRANSLOADIT_KEY",
  "secret" => "MY_TRANSLOADIT_SECRET",
]);

// Start the Assembly
$response = $transloadit->createAssembly([
  "files" => ["dutch-anthem.mp3"],
  "params" => [
    "steps" => [
      ":original" => [
        "robot" => "/upload/handle",
      ],
      "imported_postroll" => [
        "robot" => "/http/import",
        "url" => "https://demos.transloadit.com/inputs/german-anthem.mp3",
      ],
      "concatenated" => [
        "use" => [
          "steps" => [
            [
              "name" => ":original",
              "fields" => "file",
              "as" => "audio_1",
            ], 
,            [
              "name" => "imported_postroll",
              "as" => "audio_2",
            ], 
          ],
        ],
        "robot" => "/audio/concat",
        "result" => true,
        "ffmpeg_stack" => "v6.0.0",
      ],
      "exported" => [
        "use" => ["imported_postroll", "concatenated", ":original"],
        "robot" => "/s3/store",
        "credentials" => "YOUR_AWS_CREDENTIALS",
        "path" => "${unique_prefix}/both-anthems.${file.ext}",
        "url_prefix" => "https://demos.transloadit.com/",
      ],
    ],
  ],
]);
# gem install transloadit

# $ irb -rubygems
# >> require 'transloadit'
# => true

transloadit = Transloadit.new([
  :key => "YOUR_TRANSLOADIT_KEY",
])

# Set Encoding Instructions
_original = transloadit.step(":original", "/upload/handle", {})

imported_postroll = transloadit.step("imported_postroll", "/http/import", [
  :url => "https://demos.transloadit.com/inputs/german-anthem.mp3"
])

concatenated = transloadit.step("concatenated", "/audio/concat", [
  :use => [
    :steps => [
      [
        :name => ":original",
        :fields => "file",
        :as => "audio_1"
      ], 
,      [
        :name => "imported_postroll",
        :as => "audio_2"
      ]
    ]
  ],
  :result => true,
  :ffmpeg_stack => "v6.0.0"
])

exported = transloadit.step("exported", "/s3/store", [
  :use => ["imported_postroll", "concatenated", ":original"],
  :credentials => "YOUR_AWS_CREDENTIALS",
  :path => "${unique_prefix}/both-anthems.${file.ext}",
  :url_prefix => "https://demos.transloadit.com/"
])

transloadit.assembly([
  :steps => [_original, imported_postroll, concatenated, exported]
])

# Add files to upload
files = []
files.push("dutch-anthem.mp3")

# Start the Assembly
response = assembly.create! *files

until response.finished?
  sleep 1; response.reload!
end

if !response.error?
  # handle success
end
# pip install pytransloadit
from transloadit import client

tl = client.Transloadit('YOUR_TRANSLOADIT_KEY', 'MY_TRANSLOADIT_SECRET')
assembly = tl.new_assembly()

# Set Encoding Instructions
assembly.add_step(":original", "/upload/handle", {})

assembly.add_step("imported_postroll", "/http/import", {
  'url': 'https://demos.transloadit.com/inputs/german-anthem.mp3'
})

assembly.add_step("concatenated", "/audio/concat", {
  'use': {
    'steps': [
      {
        'name': ':original',
        'fields': 'file',
        'as': 'audio_1'
      }, 
,      {
        'name': 'imported_postroll',
        'as': 'audio_2'
      }
    ]
  },
  'result': True,
  'ffmpeg_stack': 'v6.0.0'
})

assembly.add_step("exported", "/s3/store", {
  'use': ['imported_postroll', 'concatenated', ':original'],
  'credentials': 'YOUR_AWS_CREDENTIALS',
  'path': '${unique_prefix}/both-anthems.${file.ext}',
  'url_prefix': 'https://demos.transloadit.com/'
})

# Add files to upload
assembly.add_file(open('dutch-anthem.mp3', 'rb'))

# Start the Assembly
assembly_response = assembly.create(retries=5, wait=True)

print(assembly_response.data.get('assembly_ssl_url'))
# or:
print(assembly_response.data['assembly_ssl_url'])
// go get gopkg.in/transloadit/go-sdk.v1
package main

import (
  "context"
  "fmt"
  "github.com/transloadit/go-sdk"
)

func main() {
  // Create client
  options := transloadit.DefaultConfig
  options.AuthKey = "YOUR_TRANSLOADIT_KEY"
  options.AuthSecret = "MY_TRANSLOADIT_SECRET"
  client := transloadit.NewClient(options)
  
  // Initialize new Assembly
  assembly := transloadit.NewAssembly()
  
  // Set Encoding Instructions
  assembly.AddStep(":original", map[string]interface{}{
    "robot": "/upload/handle",
  })
  
  assembly.AddStep("imported_postroll", map[string]interface{}{
    "robot": "/http/import",
    "url": "https://demos.transloadit.com/inputs/german-anthem.mp3",
  })
  
  assembly.AddStep("concatenated", map[string]interface{}{
    "use": map[string]interface{}{
      "steps": [
        map[string]interface{}{
          "name": ":original",
          "fields": "file",
          "as": "audio_1",
        }, 
  ,      map[string]interface{}{
          "name": "imported_postroll",
          "as": "audio_2",
        }, 
      ],
    },
    "robot": "/audio/concat",
    "result": true,
    "ffmpeg_stack": "v6.0.0",
  })
  
  assembly.AddStep("exported", map[string]interface{}{
    "use": ["imported_postroll", "concatenated", ":original"],
    "robot": "/s3/store",
    "credentials": "YOUR_AWS_CREDENTIALS",
    "path": "${unique_prefix}/both-anthems.${file.ext}",
    "url_prefix": "https://demos.transloadit.com/",
  })
  
  // Add files to upload
  assembly.AddFile("dutch-anthem.mp3"))
  
  // Start the Assembly
  info, err := client.StartAssembly(context.Background(), assembly)
  if err != nil {
    panic(err)
  }
  
  // All files have now been uploaded and the Assembly has started but no
  // results are available yet since the conversion has not finished.
  // WaitForAssembly provides functionality for polling until the Assembly
  // has ended.
  info, err = client.WaitForAssembly(context.Background(), info)
  if err != nil {
    panic(err)
  }
  
  fmt.Printf("You can check some results at: ")
  fmt.Printf("  - %s\n", info.Results[":original"][0].SSLURL)
  fmt.Printf("  - %s\n", info.Results["imported_postroll"][0].SSLURL)
  fmt.Printf("  - %s\n", info.Results["concatenated"][0].SSLURL)
  fmt.Printf("  - %s\n", info.Results["exported"][0].SSLURL)
}
// implementation 'com.transloadit.sdk:transloadit:1.0.0

import com.transloadit.sdk.Assembly;
import com.transloadit.sdk.Transloadit;
import com.transloadit.sdk.exceptions.LocalOperationException;
import com.transloadit.sdk.exceptions.RequestException;
import com.transloadit.sdk.response.AssemblyResponse;
import java.io.File;
import java.util.HashMap;
import java.util.Map;

public class Main {
  public static void main(String[] args) {
    // Initialize the Transloadit client
    Transloadit transloadit = new Transloadit("YOUR_TRANSLOADIT_KEY", "MY_TRANSLOADIT_SECRET");
    
    Assembly assembly = transloadit.newAssembly();
    
    // Set Encoding Instructions
    Map<String, Object> _originalStepOptions = new HashMap();
    assembly.addStep(":original", "/upload/handle", _originalStepOptions);
    
    Map<String, Object> imported_postrollStepOptions = new HashMap();
    imported_postrollStepOptions.put("url", "https://demos.transloadit.com/inputs/german-anthem.mp3");
    assembly.addStep("imported_postroll", "/http/import", imported_postrollStepOptions);
    
    Map<String, Object> concatenatedStepOptions = new HashMap();
    concatenatedStepOptions.put("use", {
        "steps": new String[] { {
          "name": ":original",
          "fields": "file",
          "as": "audio_1",
        }, {
          "name": "imported_postroll",
          "as": "audio_2",
        } },
      });
    concatenatedStepOptions.put("result", true);
    concatenatedStepOptions.put("ffmpeg_stack", "v6.0.0");
    assembly.addStep("concatenated", "/audio/concat", concatenatedStepOptions);
    
    Map<String, Object> exportedStepOptions = new HashMap();
    exportedStepOptions.put("use", new String[] { "imported_postroll", "concatenated", ":original" });
    exportedStepOptions.put("credentials", "YOUR_AWS_CREDENTIALS");
    exportedStepOptions.put("path", "${unique_prefix}/both-anthems.${file.ext}");
    exportedStepOptions.put("url_prefix", "https://demos.transloadit.com/");
    assembly.addStep("exported", "/s3/store", exportedStepOptions);
    
    // Add files to upload
    assembly.addFile(new File("dutch-anthem.mp3"));
    
    // Start the Assembly
    try {
      AssemblyResponse response = assembly.save();
    
      // Wait for Assembly to finish executing
      while (!response.isFinished()) {
        response = transloadit.getAssemblyByUrl(response.getSslUrl());
      }
    
      System.out.println(response.getId());
      System.out.println(response.getUrl());
      System.out.println(response.json());
    } catch (RequestException | LocalOperationException e) {
      // Handle exception here
    }
  }
}

So many ways to integrate

Transloadit is a service for companies with developers. As a developer, there are many ways you can put us to good use.
  • 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.

Try it in your account

Copy these instructions to a Template of your own
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