Configs

Values your workflow code reads per environment.

Settings → Configs

With nothing configured yet, the page reads No configs yet above the line that explains the feature:

The Configs page before any config exists. Read a config from workflow code with fastn.envConfig.get("key").

A config holds anything that changes between test and live, like an endpoint or a feature flag. Read one with fastn.envConfig.get.

const endpoint  = await fastn.envConfig.get("PARTNER_API_BASE");
const batchSize = await fastn.envConfig.get("BATCH_SIZE");

Creating one

Add config opens the Add Config dialog, which takes two things.

Key * is the string your code passes: fastn.envConfig.get("PARTNER_API_BASE") reads the config whose key is PARTNER_API_BASE.

Values per environment is one editor per environment, labelled with the display name and the slug: Test (test), Live (live), and a row for each named environment you have added. A value may be raw text or valid JSON.

Leaving an environment's editor blank skips that environment on save: it does not write an empty value. That is usually what you want when you are only setting up test, but it means a config can silently have no value in live.

The same key resolves to a different value depending on which environment the run is in, so your code never branches on environment.

Configs versus secrets

A config's value is entered and edited in the dashboard rather than written once and hidden, which is the practical difference from a secret: you can see what an environment is set to without running anything. Treat that as the working assumption: anything whose exposure would be an incident belongs in a secret regardless.

Choosing between a config and a secret

Use a config for	Use a secret for
Base URLs and endpoints	API tokens and passwords
Feature flags	Signing and encryption keys
Batch sizes, page sizes, thresholds	Database connection strings
Anything you would happily show a colleague	Anything whose exposure is an incident

When in doubt, use a secret. A config that turns out to be sensitive is already visible to everyone who can read settings.

A common pattern

Point test at a sandbox and live at production, without a line of conditional code:

Config	test	live
PARTNER_API_BASE	https://sandbox.partner.example	https://api.partner.example
BATCH_SIZE	10	500
DRY_RUN	true	false

Which environment a run uses is decided by the x-fastn-env header or the trigger route. See Environments.