field. Each step references a previous step's output:
{
"steps"
:
{
"resized"
:
{
"robot"
:
"/image/resize"
,
"use"
:
":original"
,
"width"
:
1920
}
,
"optimized"
:
{
"robot"
:
"/image/optimize"
,
"use"
:
"resized"
}
,
"exported"
:
{
"robot"
:
"/s3/store"
,
"use"
:
"optimized"
,
"bucket"
:
"my-bucket"
,
"path"
:
"processed/${file.name}"
}
}
}
Key Concepts
Assembly
A single processing job. Created via
create_assembly
(MCP) or
assemblies create
(CLI).
Template
A reusable set of steps stored on Transloadit. Created via
create_template
(MCP) or
templates create
(CLI).
Robot
A processing unit (e.g.,
/video/encode
,
/image/resize
). See full list at
https://transloadit.com/docs/transcoding/
Steps
JSON object defining the pipeline. Each key is a step name, each value configures a robot.
:original
Refers to the uploaded input file.
Tips
Use
--wait
with the CLI to block until processing completes.
Use
preset
values (e.g.,
"hls-1080p"
,
"mp3"
,
"webp"
) for common format targets instead of specifying every parameter.
Chain
"use": "step_name"
to build multi-step pipelines without intermediate downloads.
For batch processing, use
/http/import
to pull files from URLs, S3, GCS, Azure, FTP, or Dropbox.
Templates can include
${variables}
for dynamic values passed at assembly creation time.