Bcrypt Hash Verifier & Generator
Verify that a plaintext password matches a bcrypt hash — or generate new hashes — entirely in your browser. Your passwords never leave your machine.
How ZeroData protects your privacy
- ✓ No Uploads: Processing happens entirely via client-side JavaScript.
- ✓ No Storage: We do not have a database. We physically cannot save your data.
- ✓ No Tracking: We don't log what you process or track your inputs.
- ✓ Verifiable: Check your DevTools Network tab. You will see 0 outbound requests.
The Irony of Online Bcrypt Tools
Bcrypt exists for one reason: to protect passwords even if a database is breached. The entire point is that the hash should be computationally expensive to reverse. So it is deeply ironic that most "online bcrypt verifiers" ask you to upload your password and hash to their server.
Think about what that means: you are sending a plaintext password and its hash to a third-party server, trusting that they won't log it. This is the exact security failure bcrypt was designed to prevent.
Our Bcrypt Hash Verifier uses the bcryptjs library compiled to run entirely in your browser's JavaScript engine. The compareSync() function executes locally, performing all 2^n iterations of the bcrypt algorithm on your CPU. Your password and hash exist only in your browser's memory and are garbage-collected when you close the tab.
We also include a hash generator with configurable cost factors (8-14 rounds) so you can create test hashes for development without needing a terminal or REPL.
How to Compare Bcrypt Hash Values Locally
To run a secure bcrypt compare, simply paste the plaintext password and target hash into the inputs above. Our client-side script parses the salt and parameters directly from the hash string, then runs the comparison calculations locally. This enables you to troubleshoot backend authentication flows and test user credentials securely.
Why Verify Bcrypt Hashes in Your Browser?
The entire point of bcrypt is that passwords should be computationally expensive to reverse — even if an attacker obtains the hash. Sending your password and hash to a third-party server for verification completely undermines this security model. Our bcrypt verifier uses the bcryptjs library running entirely in your browser's JavaScript engine. The compareSync() function executes all 2n iterations locally on your CPU. Your password and hash exist only in browser memory and are garbage-collected when you close the tab.
Need to generate other types of hashes? Use our Hash Generator for SHA-256, SHA-512, and bcrypt hash creation — all running locally via the Web Crypto API.
Common Use Cases
- Verifying that a user's password matches the hash stored in your database during debugging.
- Testing bcrypt hash generation in different languages to ensure compatibility.
- Checking if a password reset flow correctly updates the stored hash.
- Generating bcrypt hashes for seed data or initial admin accounts in development.
- Auditing bcrypt cost factors to ensure they meet current security recommendations.
Frequently Asked Questions
How does bcrypt verification work?
Bcrypt hashes contain the salt and cost factor embedded in the hash string itself. The verifier extracts the salt, hashes your plaintext password with the same salt and cost factor, and compares the result to the stored hash. If they match, the password is correct.
Is it safe to paste my password hash here?
Yes. The bcryptjs library runs entirely in your browser via JavaScript. Your password and hash are never transmitted to any server. This is exactly why we built this tool — most online bcrypt verifiers upload your data, which defeats the purpose of using bcrypt in the first place.
What do the cost factor rounds mean?
The cost factor (e.g., 10 in $2a$10$...) determines how many iterations the algorithm performs. Each increment doubles the work: cost 10 = 1,024 iterations, cost 12 = 4,096 iterations. Higher costs are more secure but slower to compute.
What bcrypt versions are supported?
This tool supports $2a$, $2b$, and $2y$ prefix variants, which cover virtually all bcrypt hashes generated by Node.js, PHP, Python, Ruby, and Go applications.
How do I run a bcrypt compare operation safely?
To perform a bcrypt compare, input your plaintext password and the bcrypt hash. The tool will compare the bcrypt hash against the plaintext value using the standard algorithm, running the verification entirely in your web browser. This ensures you can verify or compare bcrypt hashes without exposing sensitive credentials to the network.
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