---
id: api/commands/spy
title: spy | Cypress Documentation
description: >-
  Wrap a method in a spy in order to record calls to and arguments of the
  function in Cypress.
section: api
source_path: docs/api/commands/spy.mdx
version: 3cf5b86b3403f604bdf7f3e35025c3bc3865e02c
updated_at: '2026-05-07T17:44:31.931Z'
---
# spy

Wrap a method in a spy in order to record calls to and arguments of the function.

`cy.spy()` is a utility function, and is not a Cypress command, query or assertion. It is not retryable, chainable, or timeout-able.

**Note:** `.spy()` assumes you are already familiar with our guide: [Stubs, Spies, and Clocks](/llm/markdown/app/guides/stubs-spies-and-clocks.md)

## Syntax

```
cy.spy(object, method)
```

### Usage

**Correct Usage**

```
cy.spy(user, 'addFriend')cy.spy(user, 'addFriend').as('addFriend')
```

### Arguments

**object _(Object)_**

The `object` that has the `method` to be wrapped.

**method _(String)_**

The name of the `method` on the `object` to be wrapped.

### Yields [Learn about subject management](/llm/markdown/app/core-concepts/introduction-to-cypress.md#Subject-Management)

*   `cy.spy()` is _synchronous_ and returns a value (the spy) instead of a Promise-like chain-able object. It can be aliased.
*   `cy.spy()` returns a [Sinon.js spy](https://sinonjs.org/releases/v8/spies/). All methods found on Sinon.JS spies are supported.

## Examples

### Method

#### Wrap a method with a spy

```
// assume App.start calls util.addListenerscy.spy(util, 'addListeners')App.start()expect(util.addListeners).to.be.called
```

#### Disable logging to Command Log

You can chain a `.log(bool)` method to disable `cy.spy()` calls from being shown in the Command Log. This may be useful when your stubs are called an excessive number of times.

```
const obj = {  foo() {},}const spy = cy.spy(obj, 'foo').log(false)
```

#### More `cy.spy()` examples

[Check out our example recipe testing spying, stubbing and time](/llm/markdown/app/references/recipes.md#Stubbing-and-spying)

### Aliases

You can alias spies, similar to how [`.as()`](/llm/markdown/api/commands/as.md) works. This can make your spies easier to identify in error messages and Cypress's command log, and allows you to assert against them later using `cy.get()`.

```
const obj = {  foo() {},}const spy = cy.spy(obj, 'foo').as('anyArgs')const withFoo = spy.withArgs('foo').as('withFoo')obj.foo()expect(spy).to.be.calledcy.get('@withFoo').should('be.called') // purposefully failing assertion
```

You will see the following in the command log:

## Notes

### Restores

#### Automatic reset/restore between tests

`cy.spy()` creates spies in a [sandbox](https://sinonjs.org/releases/v8/sandbox/), so all spies created are automatically reset/restored between tests without you having to explicitly reset/restore them.

### Differences

#### Difference between cy.spy() and cy.stub()

The main difference between `cy.spy()` and [`cy.stub()`](/llm/markdown/api/commands/stub.md) is that `cy.spy()` does not replace the method, it only wraps it. So, while invocations are recorded, the original method is still called. This can be very useful when testing methods on native browser objects. You can verify a method is being called by your test and still have the original method action invoked.

### Assertions

#### Assertion Support

Cypress has also built-in [Sinon-Chai](/llm/markdown/app/references/bundled-libraries.md#Sinon-Chai) support, so any [assertions supported by `Sinon-Chai`](/llm/markdown/app/references/assertions.md#Sinon-Chai) can be used without any configuration.

## Command Log

**_Create a spy, alias it, and call it_**

```
const obj = {  foo() {},}const spy = cy.spy(obj, 'foo').as('foo')obj.foo('foo', 'bar')expect(spy).to.be.called
```

The command above will display in the Command Log as:

When clicking on the `spy-1` event within the command log, the console outputs the following:

## History

| Version | Changes |
| --- | --- |
| [0.20.0](/llm/markdown/app/references/changelog.md#0-20-0) | Added `.log(bool)` method |
| [0.18.8](/llm/markdown/app/references/changelog.md#0-18-8) | `cy.spy()` command added |

## See also

*   [`.as()`](/llm/markdown/api/commands/as.md)
*   [`cy.clock()`](/llm/markdown/api/commands/clock.md)
*   [Guide: Stubs, Spies and Clocks](/llm/markdown/app/guides/stubs-spies-and-clocks.md)
*   [Recipe: Stubbing, Spying](/llm/markdown/app/references/recipes.md#Stubbing-and-spying)
*   [`cy.stub()`](/llm/markdown/api/commands/stub.md)