What is an Assembly Notification?
A Transloadit Assembly Notification is an optional POST request sent to a specified URL after an Assembly finishes. Its payload contains the resulting Assembly Status.
How Assembly Notifications work
A notification is a server-to-server completion delivery that pushes the final job representation to an application endpoint. It decouples media processing from the lifetime of the originating HTTP connection and therefore fits durable background workflows. The receiver should verify authenticity, persist the execution identity, and acknowledge only after safe handling. Delivery semantics also require duplicate-safe business logic rather than assuming a single request.
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
- 1The notification body carries Assembly status data, letting a receiver correlate the event, inspect terminal outcome, and locate results without keeping the upload request open.
- 2A non-success response from the callback endpoint can lead to another delivery attempt, so side effects such as publishing or billing need an idempotency guard keyed by the Assembly.
- 3Because the destination is an application-controlled URL, endpoint availability, TLS configuration, authentication checks, and response latency all affect reliable handoff.
When Assembly Notifications matter
Use notifications instead of continuous polling when a system can receive asynchronous completion events. Authenticate and make the receiver idempotent, because forged or repeated requests must not duplicate work.
- 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 Notifications.
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 Notifications
When Assembly Notifications 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.