What are Assembly Instructions?
Transloadit Assembly Instructions define the Steps performed on uploaded or imported files. The back end uses them to determine file conversion, encoding, routing, and related processing behavior.
How Assembly Instructions work
Instructions form a directed processing graph expressed as named Step configurations and their input relationships. Each Step selects a Robot and parameters, while references determine which uploads or prior results flow into it. This is distinct from an Assembly, which is one execution of that graph, and from a Template, which persists the graph for reuse. The instruction set is the workflow contract validated before media processing begins.
A client authenticates and submits files or references together with workflow instructions. The platform validates the request, schedules dependent operations, records state transitions, and exposes results through a response, polling endpoint, or notification.
Platform concepts become reliable only when their lifecycle is explicit. Authentication, idempotency, retries, timeouts, observability, quotas, and terminal states should be designed together rather than added after failures occur.
Key facts
- 1Step names serve as graph identifiers, so renaming a producer without updating its consumers breaks dependency resolution even if every Robot option remains valid.
- 2A single upstream result can feed several later Steps, enabling derivative generation without repeating the import or upload stage for each output branch.
- 3Keeping Instructions in a Template moves reusable workflow logic out of the client request and enables server-side control over which processing graph is executed.
When Assembly Instructions matter
Keep Instructions in a Template when workflows need controlled reuse or features such as eligible replay. Validate Step dependencies carefully, because a missing input reference can block downstream results.
- Running repeatable upload, import, processing, AI, storage, and notification pipelines.
- Tracking long-running media work independently from an application request.
- Applying credentials, quotas, retries, and error policies consistently across integrations.
Working with platform at scale
Guidance that holds across every platform term in this glossary, not just Assembly Instructions.
What you gain
- Reusable workflows separate application intent from processing infrastructure.
- Stable job identifiers and lifecycle events improve observability and recovery.
- Managed queues and workers let products scale without embedding every media tool.
What it costs
- Synchronous responses are simple but keep connections open while long work executes.
- Aggressive retries improve recovery from transient faults but can duplicate work or overload a dependency.
- Higher concurrency reduces queue time until resource contention or a downstream limit becomes the bottleneck.
Answer these before production
- 1Define authentication, authorization, idempotency, retries, and terminal error behavior.
- 2Observe queue time, execution time, callbacks, and partial results with stable identifiers.
- 3Exercise malformed, duplicate, interrupted, and unauthorized requests before launch.
How Transloadit helps with Assembly Instructions
When Assembly Instructions are relevant to your workflow, you can hand the surrounding platform work to Transloadit instead of maintaining the processing stack yourself. Transloadit models file workflows as reusable Assembly Instructions. Upload, import, processing, AI, storage, delivery, status updates, and error handling can be composed without operating the underlying media tools yourself.
Support for a specific codec, container, parameter, or combination can vary by Robot and processing stack. Check the linked documentation for the exact inputs and outputs available for your use case.