Bearer Token Generator for HTTP Authorization Headers

How to use the bearer token generator

1. Set the token length between 8 and 256 characters.
2. Pick a character set: hexadecimal, alphanumeric or base64url.
3. Click Generate to produce a new random bearer token.
4. Copy the raw token or the complete Authorization header from the results.

What is a bearer token?

A bearer token is an opaque string used in HTTP authentication. When a client sends a request to a protected resource, it includes the token in the Authorization header using the Bearer scheme defined in RFC 6750. The server validates the token and grants access without requiring additional credentials.

The word "bearer" means that whoever holds the token can use it. There is no proof of identity beyond possession of the string itself. This makes secure transport over HTTPS essential, because anyone who intercepts the token can impersonate the legitimate holder.

How the Authorization header works

The HTTP specification requires the header to follow a strict format. The scheme name comes first, followed by a single space, then the token value:

Authorization: Bearer <token>

The scheme name is case-insensitive, but convention uses a capital B. The token itself must not contain spaces, quotes or control characters. If you are building a custom API, you can generate a static token with this bearer token generator and compare incoming requests against it on the server side.

Choosing a character set and length

The security of a random token depends on its entropy, measured in bits. Entropy equals the token length multiplied by the logarithm base 2 of the alphabet size. Here is how the three available character sets compare:

For most applications, 128 bits of entropy is considered strong enough to resist brute-force attacks. A 32-character hexadecimal token meets that threshold. If you need higher assurance, choose alphanumeric or base64url at the same length, or increase the token length.

Common mistakes when handling bearer tokens

Developers frequently make errors that weaken the security of bearer tokens. Avoid these pitfalls:

• Sending tokens over plain HTTP. Always use HTTPS so the header cannot be read in transit.
• Logging the full header. Server logs should mask or truncate tokens to prevent accidental exposure.
• Using predictable values. Timestamps, sequential IDs or short strings are trivially guessable. Use a proper bearer token generator backed by a cryptographic random source instead.
• Storing tokens in local storage on the client. Prefer httpOnly cookies or memory-only storage to reduce cross-site scripting risk.

Bearer tokens versus other authentication schemes

Bearer tokens are one of several ways to authenticate HTTP requests. Basic authentication encodes a username and password in base64, which is reversible and therefore weaker unless combined with TLS. For more complex needs, tools like the basic auth header generator can help construct those headers correctly.

JSON Web Tokens (JWTs) are a structured form of bearer token that carry claims inside the payload. You can inspect them with a JWT decoder or create them with a JWT generator. Opaque tokens generated here have no internal structure, which simplifies validation: the server only needs to look up the string in a database or cache.

If you need general-purpose credentials rather than HTTP-specific ones, an API key and token generator may suit your workflow better.

Worked examples