API-first setup pattern in Cypress

Introduction

The API-first setup pattern helps prepare test data quickly and reliably by using backend APIs before running UI tests.

When you need to create test users or data before testing the app UI.

When UI setup is slow or flaky, and you want faster test preparation.

When you want to isolate UI tests from data creation steps.

When you want to reuse setup steps across many tests.

When you want to keep tests clean and focused on UI behavior.

Syntax

Cypress

cy.request({
  method: 'POST',
  url: '/api/users',
  body: { username: 'testuser', password: 'pass123' }
}).then((response) => {
  expect(response.status).to.eq(201)
  // use response data for next steps
})

Use cy.request() to call backend APIs directly.

Check the response status to confirm setup success.

Examples

Simple POST request to login API with assertion on status code.

Cypress

cy.request('POST', '/api/login', { username: 'user1', password: 'pwd' })
  .then((res) => {
    expect(res.status).to.eq(200)
  })

Delete a user by ID before running tests to ensure clean state.

Cypress

cy.request({
  method: 'DELETE',
  url: '/api/users/123'
}).then((res) => {
  expect(res.status).to.eq(204)
})

Fetch list of products to verify API returns data before UI tests.

Cypress

cy.request({
  method: 'GET',
  url: '/api/products'
}).then((res) => {
  expect(res.body).to.have.length.greaterThan(0)
})

Sample Program

This test suite uses API calls to create a user before tests, then tests login via UI, and finally deletes the user after tests.

Cypress

describe('API-first setup example', () => {
  before(() => {
    // Create a test user via API
    cy.request({
      method: 'POST',
      url: '/api/users',
      body: { username: 'testuser', password: 'pass123' }
    }).then((response) => {
      expect(response.status).to.eq(201)
      cy.wrap(response.body.id).as('userId')
    })
  })

  it('logs in with the created user', function () {
    cy.visit('/login')
    cy.get('input[name=username]').type('testuser')
    cy.get('input[name=password]').type('pass123')
    cy.get('button[type=submit]').click()
    cy.url().should('include', '/dashboard')
    cy.contains('Welcome, testuser').should('be.visible')
  })

  after(function () {
    // Clean up by deleting the test user
    cy.request({
      method: 'DELETE',
      url: `/api/users/${this.userId}`
    }).then((res) => {
      expect(res.status).to.eq(204)
    })
  })
})

Important Notes

Always verify API responses to catch setup errors early.

Use aliases (cy.wrap(...).as()) to share data between hooks and tests.

Cleaning up test data after tests keeps your environment stable.

Summary

API-first setup uses backend calls to prepare test data before UI tests.

This pattern makes tests faster and more reliable.

Remember to verify API responses and clean up after tests.

Practice

1. What is the main benefit of using the API-first setup pattern in Cypress tests?

easy

A. It prepares test data quickly by calling backend APIs before UI tests run.

B. It replaces UI tests completely with API tests.

C. It slows down tests by adding extra API calls.

D. It only works for frontend UI testing without backend interaction.

Solution

1. Step 1: Understand API-first setup purpose

   API-first setup means using backend API calls to prepare data before UI tests.

2. Step 2: Identify the benefit

   This approach makes tests faster and more reliable by avoiding UI data entry steps.

3. Final Answer:

   It prepares test data quickly by calling backend APIs before UI tests run. -> Option A

4. Quick Check:

   API-first setup = faster, reliable test data setup [OK]

Hint: API-first means setup via backend calls before UI tests [OK]

Common Mistakes:

• Thinking API-first replaces UI tests
• Assuming API calls slow down tests
• Believing API-first only works on frontend

2. Which of the following is the correct way to make an API call in Cypress for setup?

easy

A. cy.fetch('POST', '/users', {name: 'John'})

B. cy.api('POST', '/users', {name: 'John'})

C. cy.call('POST', '/users', {name: 'John'})

D. cy.request('POST', '/users', {name: 'John'})

Solution

1. Step 1: Recall Cypress API call syntax

   Cypress uses cy.request() to make HTTP requests.

2. Step 2: Match correct method and parameters

   cy.request('POST', url, body) is the correct syntax.

3. Final Answer:

   cy.request('POST', '/users', {name: 'John'}) -> Option D

4. Quick Check:

   Use cy.request() for API calls in Cypress [OK]

Hint: Use cy.request() for API calls in Cypress [OK]

Common Mistakes:

• Using cy.api() which is not a Cypress command
• Using cy.call() or cy.fetch() which don't exist in Cypress
• Mixing up method names or parameters

3. Given this Cypress test snippet using API-first setup:

cy.request('POST', '/api/users', {name: 'Alice'}).then((response) => {
  expect(response.status).to.eq(201)
  cy.visit('/users/' + response.body.id)
})

What will happen if the API returns status 400 instead of 201?

medium

A. The test will continue and visit the user page anyway.

B. The test will throw a syntax error.

C. The test will fail at the assertion checking response.status.

D. The test will ignore the response and pass.

Solution

1. Step 1: Analyze the assertion on response status

   The test expects response.status to equal 201.

2. Step 2: Understand behavior if status is 400

   If status is 400, the assertion expect(response.status).to.eq(201) fails and test stops with failure.

3. Final Answer:

   The test will fail at the assertion checking response.status. -> Option C

4. Quick Check:

   Assertion fails if response.status != 201 [OK]

Hint: Assertion fails if API response status is unexpected [OK]

Common Mistakes:

• Assuming test continues after failed assertion
• Thinking Cypress throws syntax error on bad status
• Believing test ignores failed API responses

4. You wrote this API-first setup code in Cypress:

cy.request('POST', '/api/items', {name: 'Book'})
  .then((res) => {
    expect(res.status).to.eq(200)
    cy.wrap(res.body.id).as('itemId')
  })
cy.get('@itemId').then((id) => {
  cy.visit(`/items/${id}`)
})

But the test fails with "Cannot read property 'then' of undefined". What is the likely cause?

medium

A. The cy.get('@itemId') runs before the alias is set.

B. The API returned status 500 causing failure.

C. The cy.request method is misspelled.

D. The cy.wrap command cannot create aliases.

Solution

1. Step 1: Understand Cypress command chaining and timing

   Cypress commands run asynchronously and in order, but alias usage requires the alias to be set before use.

2. Step 2: Identify timing issue with alias usage

   cy.get('@itemId') is called immediately, before the alias is set inside the then callback, causing undefined error.

3. Final Answer:

   The cy.get('@itemId') runs before the alias is set. -> Option A

4. Quick Check:

   Alias must be set before cy.get() uses it [OK]

Hint: Set alias before using cy.get('@alias') to avoid timing errors [OK]

Common Mistakes:

• Assuming API error causes this specific error
• Thinking cy.request is misspelled
• Believing cy.wrap cannot create aliases

5. You want to use API-first setup to create multiple users before a UI test. Which approach correctly ensures all users are created before visiting the page?

const users = [
  {name: 'Anna'},
  {name: 'Ben'},
  {name: 'Cara'}
]

// Which code snippet is correct?

hard

A. users.forEach(user => {
cy.request('POST', '/api/users', user)
cy.visit('/users')
})

B. cy.wrap(users).each(user => {
cy.request('POST', '/api/users', user)
}).then(() => {
cy.visit('/users')
})

C. for (const user of users) {
cy.request('POST', '/api/users', user)
cy.visit('/users')
}

D. cy.wrap(users).each(user => {
cy.request('POST', '/api/users', user)
})
cy.visit('/users')

Solution

1. Step 1: Understand Cypress command queue and async behavior

   Cypress commands like cy.request are asynchronous and queued. To wait for all requests, use cy.wrap().each() with a .then() callback.

2. Step 2: Analyze each option

   The native forEach and for-of options place cy.visit() inside the loop, causing visits after each request instead of after all. The cy.wrap(users).each(...) cy.visit() executes visit before requests due to queuing. Only cy.wrap(users).each(...).then(() => cy.visit()) waits for all requests before visiting.

3. Final Answer:

   cy.wrap(users).each(user => { cy.request('POST', '/api/users', user) }).then(() => { cy.visit('/users') }) -> Option B

4. Quick Check:

   Use cy.wrap().each() with then() to wait before next step [OK]

Hint: Chain .then() after cy.wrap().each() to wait for all API calls [OK]

Common Mistakes:

• Placing cy.visit() inside the forEach or for-of loop
• Using cy.wrap().each() without .then() afterward
• Not chaining .then() to wait for all iterations