workflow-tester

Find the payloads that break your n8n workflow before someone sends them. When a webhook arrives with a field set to null or an optional object missing, n8n turns the broken expression into undefined and shows no error. workflow-tester runs your workflow's expressions against those payloads and tells you which ones break and where. It runs offline, with no n8n instance.

Installation

Requires Node.js 24 or newer.

Run it without installing:

npx workflow-tester --help

Add it to a project:

npm install --save-dev workflow-tester

Build from source:

git clone https://github.com/LudwigGerdes/workflow-tester.git
cd workflow-tester
pnpm install && pnpm build

Getting started

Set up a project:

npx workflow-tester init

This creates:

.workflow-tester/
├── README.md
└── tests/
    └── example.test.yaml

Download a sample sign-up workflow and a test file with three cases, then run them:

curl -L --create-dirs -o workflows/signup.json https://raw.githubusercontent.com/LudwigGerdes/workflow-tester/main/docs/demo/signup.json
curl -L -o .workflow-tester/tests/signup.test.yaml https://raw.githubusercontent.com/LudwigGerdes/workflow-tester/main/docs/demo/signup.test.yaml
npx workflow-tester run

Expected output:

workflows/signup.json
  ✗ no profile object, flat name — the ?? gotcha  1 expectation(s) fail
      ✗ node.Normalize.output[0].json.name: expected "Bob", got undefined
      ! "profile" is not produced here  at Normalize → assignments.assignments[1].value
      ! "plan" is not produced here  at Normalize → assignments.assignments[2].value
  ! no email at all  every expectation held
      ! "email" is not produced here  at Normalize → assignments.assignments[0].value
      ! "profile" is not produced here  at Normalize → assignments.assignments[1].value
      ! "plan" is not produced here  at Normalize → assignments.assignments[2].value
      ! "email" is not produced here  at Normalize → assignments.assignments[3].value
  ✓ pro user with nested profile

1 passed, 1 failed, 1 warned in 354ms

The first case fails because the workflow reads $json.body.profile.first_name when there is no profile.

Usage

Write a test by hand, in .workflow-tester/tests/:

workflow: ../../workflows/signup.json
cases:
  - id: flat-name
    when:
      trigger: webhook
      payload:
        email: bob@example.com
        name: Bob
    then:
      node.Normalize.output[0].json.name: Bob

Run every test:

workflow-tester run

Generate tests from the payloads GitHub or Stripe can send:

workflow-tester contracts add workflows/issue-triage.json --vendor github --events issues-opened
workflow-tester gen
workflow-tester run --only generated

Turn a run you already made in n8n into a test:

workflow-tester capture workflows/invoice.json --execution execution.json

Report in a format your CI understands:

workflow-tester run --format junit