Local Dev with Render Workflows

Run tasks locally for faster development and testing.

Render Workflows is in public beta.

During the beta, bugs or changes in API/SDK behavior are possible as we continue refining the product. We welcome any and all feedback at workflows-feedback@render.com.

You can run workflow tasks on your local machine to iterate on them quickly. The Render CLI supports spinning up a local task server that simulates the entire run execution lifecycle. You can trigger task runs from your application code, or from the CLI itself.

As you iterate on your task definitions, the local task server picks up changes automatically. It also retains in-memory logs and results for each run (these are lost on server shutdown).

Prerequisites

Your development machine must have:

The Render CLI version 2.12.0 or later
- Install the Render CLI
A workflow project repo that defines and registers tasks
- Create your first workflow

Starting the task server

From your workflow project repo, run the following command:

shell

$ render workflows dev -- <WORKFLOW_START_COMMAND>

Replace <WORKFLOW_START_COMMAND> with the command to start your workflow service, such as:

shell

$ render workflows dev -- npm start

shell

$ render workflows dev -- python main.py

Command not found?

Make sure you've installed the Render CLI.
Run render --version to confirm you're using version 2.12.0 or later.

Your local task server spins up and starts listening on port 8120.

You can specify a different port with the --port option:

shell

$ render workflows dev --port 8121 -- python main.py

Triggering local task runs

In application code

This section assumes you have an existing app that triggers task runs.

If you don't, first get set up with Triggering Task Runs.

You can configure your locally running apps to point to your local task server when triggering task runs. How you do this depends on whether your app uses the Render SDK or the Render API:

If your app uses the Render SDK (TypeScript or Python) to trigger task runs, set the following environment variable(s) to run tasks against your local task server:

.env

bash

# Always set this:
RENDER_USE_LOCAL_DEV=true

# Also set this if you're using a non-default URL/port:
# RENDER_LOCAL_DEV_URL=http://localhost:8121

If your app uses the Render API directly to run tasks, swap out the base URL you use for task-related endpoints with your local task server's URL.

Here's a Node.js example:

const TASKS_BASE_URL = process.env.RENDER_TASKS_URL || 'https://api.render.com'

In this example, you would set the RENDER_TASKS_URL environment variable to your local task server URL (e.g., http://localhost:8120) to use it for development.

Note that the local task server only simulates task-related endpoints. Other Render API endpoints are not supported.

In the Render CLI

With your local task server running, run the following command:
shell
```
$ render workflows tasks list --local
```
Don't forget the --local flag! Otherwise, the CLI lists tasks from your deployed workflow services.

The CLI opens an interactive menu of your locally registered tasks:
Select a task and press Enter, then select the run command.

The CLI prompts you to provide the task's input arguments as a JSON array:

If your task takes zero arguments, provide an empty list, [].
Provide your desired arguments and press Enter. The CLI kicks off your task with a request to your local task server and begins tailing its logs.

You can remain in this view to view live logs from your task run.
Press Esc to navigate back up to the list of commands for your task. This time select the runs command.

The CLI opens an interactive menu of the task's local runs:
Select a run and press Enter, then select the results command.

The CLI opens a view of the run's results:

In non-interactive environments, provide any of -o text, -o json, or -o yaml to Render CLI commands to disable menu navigation and receive output in the desired format.

The example commands below use -o text:

With your local task server running, run the following command to list your locally registered tasks:

shell

$ render workflows tasks list -o text --local
  NAME               ID                          CREATED                      
  calculateSquare    tsk-d6kba95mo5j36bpg8rs0    2026-03-04T14:41:40-08:00    
  sumSquares         tsk-d6kba95mo5j36bpg8rsg    2026-03-04T14:41:40-08:00    
  flipCoin           tsk-d6kba95mo5j36bpg8rt0    2026-03-04T14:41:40-08:00

Don't forget the --local flag for all of these commands! Otherwise, the CLI runs them against your deployed workflow services.

Start a run for that task, passing input as a JSON array:

shell

$ render workflows tasks start calculateSquare -o text --input='[3]' --local
  Created task run trn-d6kchpdmo5j36bpg8rvg for calculateSquare

List runs for the task:

shell

$ render workflows runs list calculateSquare -o text --local
  ID                          STATUS       STARTED                      COMPLETED                    DURATION     
  trn-d6kchpdmo5j36bpg8rvg    completed    2026-03-04T16:05:57-08:00    2026-03-04T16:05:57-08:00    364.577ms

Fetch details and results for a run by its ID:

shell

$ render workflows runs show calculateSquare -o text --local
  Task run details for trn-d6kchpdmo5j36bpg8rvg: status completed, started at 2026-03-04 16:05:57.371701 -0800 PST, completed at 2026-03-04 16:05:57.736278 -0800 PST,
  input: [3],
  results: [9]

Local-only considerations

Logs and results for local task runs are stored in memory by the local task server.
- This data is lost when the server shuts down.
- This data is retained indefinitely as long as the server is running. This can lead to high memory usage over time.
- If you trigger a high volume of local task runs, we recommend periodically restarting your local task server to free up memory.
Identifiers for local tasks and runs are randomly generated IDs.
- The identifier for a given task differs each time you run the local task server.
- Local identifiers do not correspond to any values in your deployed workflow services.