vercel bisect

Last updated February 14, 2025

The vercel bisect command can be used to perform a binary search upon a set of deployments in a Vercel Project for the purpose of determining when a bug was introduced.

This is similar to git bisect but faster because you don't need to wait to rebuild each commit, as long as there is a corresponding Deployment. The command works by specifing both a bad Deployment and a good Deployment. Then, vercel bisect will retrieve all the deployments in between, and step by them one by one. At each step, you will perform your check and specify whether or not the issue you are investigating is present in the Deployment for that step.

Note that if an alias URL is used for either the good or bad deployment, then the URL will be resolved to the current target of the alias URL. So if your Project is currently in promote/rollback state, then the alias URL may not be the newest chronological Deployment.

The good and bad deployments provided to vercel bisect must be production deployments.

Usage

terminal

vercel bisect

Using the vercel bisect command will initiate an interactive prompt where you specify a good deployment, followed by a bad deployment and step through the deployments in between to find the first bad deployment.

Unique Options

These are options that only apply to the vercel bisect command.

Good

The --good option, shorthand -g, can be used to specify the initial "good" deployment from the command line. When this option is present, the prompt will be skipped at the beginning of the bisect session. A production alias URL may be specified for convenience.

terminal

vercel bisect --good https://example.com

Using the vercel bisect command with the --good option.

Bad

The --bad option, shorthand -b, can be used to specify the "bad" deployment from the command line. When this option is present, the prompt will be skipped at the beginning of the bisect session. A production alias URL may be specified for convenience.

terminal

vercel bisect --bad https://example-s93n1nfa.vercel.app

Using the vercel bisect command with the --bad option.

Path

The --path option, shorthand -p, can be used to specify a subpath of the deployment where the issue occurs. The subpath will be appended to each URL during the bisect session.

terminal

vercel bisect --path /blog/first-post

Using the vercel bisect command with the --path option.

Open

The --open option, shorthand -o, will attempt to automatically open each deployment URL in your browser window for convenience.

terminal

vercel bisect --open

Using the vercel bisect command with the --open option.

Run

The --run option, shorthand -r, provides the ability for the bisect session to be automated using a shell script or command that will be invoked for each deployment URL. The shell script can run an automated test (for example, using the curl command to check the exit code) which the bisect command will use to determine whether each URL is good (exit code 0), bad (exit code non-0), or should be skipped (exit code 125).

terminal