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One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchFor a browser-level upload, use Cypress’s .selectFile() command on the file input, usually with a project-relative path. For a browser-triggered download, trigger the application’s download action, then read the resulting file from Cypress’s downloadsFolder and assert on its contents. Use cy.request() and cy.writeFile() instead when you want to test an HTTP transfer directly rather than the browser UI.
Upload a file through the browser UI
.selectFile() is the Cypress command for populating a file input. It must be chained from a command that yields a DOM element; in ordinary selection mode, that subject must be one input[type="file"] or a connected label.
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Use a project file
When the file already exists in the project, pass its project-relative path directly:
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.selectFile('cypress/fixtures/example.pdf')Cypress recommends this approach for files on disk because it avoids many encoding-related pitfalls.
Use a fixture alias for reusable binary data
For a fixed binary fixture you want to load and refer to by alias, use null encoding so Cypress yields a buffer:
cy.fixture('images/avatar.png', null).as('avatar')
cy.get('input[type="file"]').selectFile('@avatar')cy.fixture() caches content for a path and encoding. If the file changes during a test or is created by the application, use cy.readFile() instead; since Cypress 13, cy.readFile() is a query and rereads the file as chained assertions retry.
Generate file contents in the test
.selectFile() also accepts an object with contents, fileName, mimeType, and lastModified. Contents can be a string, TypedArray or Cypress.Buffer, a path, or an alias. Set a meaningful filename so the application receives the expected name. Cypress can infer MIME type from a recognized extension; set mimeType explicitly when needed. If omitted, lastModified defaults to the current time.
const contents = Cypress.Buffer.from('id,namen1,Adan')
cy.get('input[type="file"]').selectFile({
contents,
fileName: 'users.csv',
mimeType: 'text/csv'
})Upload multiple files or simulate a drop
Pass an array for multiple files, but only if the input has the multiple property. To test a drop target, make that target the subject and set action: 'drag-drop'. If the application listens for drops at the page level, body can be the subject because drop events bubble to document listeners.
cy.get('input[type="file"][multiple]')
.selectFile([
'cypress/fixtures/first.pdf',
'cypress/fixtures/second.pdf'
])
cy.get('[data-cy="drop-zone"]')
.selectFile('cypress/fixtures/example.pdf', { action: 'drag-drop' })A hidden file input can be selected with { force: true } when the visible upload control activates it but Cypress’s normal actionability checks prevent the test from interacting with it. Use that only when it reflects how the application’s UI works.
Choose the right upload workflow
| What you are testing | Use | Why |
|---|---|---|
| Existing file selected in the UI | .selectFile('project-relative-path') |
Direct path is the preferred disk-file approach and avoids needless encoding conversions. |
| Fixed test fixture reused by a test | cy.fixture(), optionally aliased |
Convenient for stable test data; use null encoding for binary fixtures. |
| Generated file or custom filename and type | .selectFile({ contents, fileName, mimeType }) |
Build contents in the test and control the file metadata seen by the application. |
| Drag-and-drop interaction | .selectFile(file, { action: 'drag-drop' }) |
Exercises the drop-target interaction rather than ordinary file selection. |
| API upload, not the browser picker | cy.request() with FormData |
Tests the HTTP upload route without simulating a user selecting a file. |
Test an API upload directly
For multipart uploads through cy.request(), Cypress documents using FormData; it preserves file bytes and supplies the multipart boundary. Leave the form option unset: that option is for URL-encoded forms. This route tests the API, not the browser file-input interaction.
Use the browser method when the user-facing selection or drop behavior matters. Use the request method when the requirement is specifically that the upload endpoint accepts the file and processes it.
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Test a browser-triggered download
Cypress saves files downloaded by the application into the configured downloadsFolder rather than opening the browser’s native Save As dialog or download shelf. The documented default folder is cypress/downloads.
cy.get('[data-cy="export"]').click()
cy.readFile('cypress/downloads/report.csv')
.should('contain', 'Total')Assert what the product requirement actually promises: expected text for a CSV or text file, required fields after parsing JSON, or exact bytes and encoding when those matter. cy.readFile() accepts explicit encodings and null to yield a Buffer, and its retry behavior is useful when the application creates the download during the test.
Use a direct request when there is no browser download interaction to test
If the requirement is to fetch an endpoint response and save it, rather than verify a user-triggered download, Cypress documents pairing cy.request() with cy.writeFile(). For a PDF response, use binary encoding; cy.writeFile() also accepts a Buffer and null encoding for writing bytes without converting them to a string. For Node-side work or large-file metadata checks that do not need a browser transfer, use cy.task(); Cypress’s custom-command examples include a download command implemented through a task.
Configure and clean up downloaded files
downloadsFolder can be set in Cypress configuration; its default is cypress/downloads. Cypress’s trashAssetsBeforeRuns setting defaults to true; before cypress run, it clears the downloads, screenshots, and videos folders, including nested subfolders. Do not rely on a file from an earlier run being present.
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Downloaded files are generated test assets. Cypress’s test-organization guidance lists cypress/downloads/, cypress/screenshots/, and cypress/videos/ as examples to ignore in source control.
Troubleshooting uploads and downloads
- “Element is not an input[type=file] or label”: Ensure the command subject is the actual file input or a connected label. For drag-and-drop, select the drop target and specify
action: 'drag-drop'. - Multiple-file selection fails: The input must have its
multipleproperty. Use a single file or update the application’s input if multiple selection is intended. - A hidden input is not actionable: If the visible control activates that input, use
{ force: true }on.selectFile()to bypass actionability checks. - Path or alias cannot be resolved: Verify that the path is project-root-relative and that the file exists, or that the fixture alias was created and referenced correctly. Cypress waits and retries for an existing path, but may time out if the path or alias cannot resolve.
- Binary fixture content is corrupted or interpreted as text: Load it with
cy.fixture(path, null)or use a Buffer; avoid unnecessary encoding conversions. - Downloaded file is missing: Confirm the application action actually starts a download, check the configured
downloadsFolder, and account for asset cleanup beforecypress run. Read the expected filename, not an assumed location outside that folder. - API upload rejects multipart data: For Cypress’s documented
FormDataworkflow, do not setform; Cypress supplies the multipart boundary.
Version notes
Cypress documents .selectFile() as added in 9.3.0, with TypedArray and mimeType support recorded in 9.4.0. The scrollBehavior option history includes a change in 15.20.0. Cypress records cy.readFile() as becoming a query in 13.0.0. These are API history markers, not a statement of the latest Cypress release.
Or skip the browser setup
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curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webpSee the ScreenshotNeo API documentation. ScreenshotNeo accepts cookie banners and removes more than 60 known consent platforms, newsletter popups, and chat widgets before capture; each of those steps can be turned off. Bot checks, blank pages, timeouts, failed loads, and cache hits are not billed. Its MCP server offers take_screenshot, get_page_info, and capture_pdf for AI agents. The free plan includes 1,000 screenshots per month with no card; paid plans start at $5 for 3,000 shots.
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Frequently Asked Questions
Can Cypress test a download without opening a browser window?
A browser-triggered application download is saved by Cypress into its downloads folder; a direct endpoint transfer can instead be requested and written to disk.
Can I select a file using a relative path?
Yes. Pass a project-root-relative file path to `.selectFile()`; this is the preferred disk-file workflow.
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