Implementation:Cypress io Cypress Install Start CI

Knowledge Sources	Cypress CI Guide
Domains	CI_CD, Package_Management
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete tool for installing and caching the Cypress binary in CI environments provided by the CLI install module.

Description

The same install.start function from cli/lib/tasks/install.ts (L195-369) is used in CI, but with CI-specific environment variables. The function checks CYPRESS_CACHE_FOLDER for custom cache locations and uses downloadAndUnzip (L81-144) for binary acquisition when the cache is cold.

Usage

Invoked automatically during npm install or yarn install in CI pipelines. Configure cache directories and version pinning via environment variables.

Code Reference

Source Location

Repository: cypress-io/cypress
File: cli/lib/tasks/install.ts
Lines: L195-369 (install.start), L81-144 (downloadAndUnzip)

Signature

const start = async (options: any = {}): Promise<any>
// Same function as standard install, CI-specific via env vars:
// CYPRESS_CACHE_FOLDER - custom cache directory
// CYPRESS_INSTALL_BINARY - version override or "0" to skip

Import

// Triggered via npm postinstall in CI
// Or: npx cypress install

I/O Contract

Inputs

Name	Type	Required	Description
CYPRESS_CACHE_FOLDER	env var	No	Custom cache directory for CI persistence
CYPRESS_INSTALL_BINARY	env var	No	Version override or "0" to skip
options.force	boolean	No	Force reinstall (invalidate cache)

Outputs

Name	Type	Description
Cached binary	Files	Binary at CYPRESS_CACHE_FOLDER/<version>/
Verification	Promise	Installation verified

Usage Examples

CircleCI Cache Configuration

# .circleci/config.yml
steps:
  - restore_cache:
      keys:
        - cypress-{{ checksum "package-lock.json" }}
  - run: npm ci
  - save_cache:
      key: cypress-{{ checksum "package-lock.json" }}
      paths:
        - ~/.cache/Cypress

GitHub Actions

- uses: actions/cache@v3
  with:
    path: ~/.cache/Cypress
    key: cypress-${{ hashFiles('package-lock.json') }}
- run: npm ci

Related Pages

Implements Principle

Principle:Cypress_io_Cypress_CI_Binary_Installation

Requires Environment

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