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CSRF Token Generator

Generate a secure random CSRF token to protect forms and requests against cross-site request forgery - Base64URL, Base64, and Hex formats

[ CSRF Tokens - Quick Summary ]

What: Generate a cryptographically secure random CSRF (Cross-Site Request Forgery) token. Supports Base64URL, Base64, Hex, and Alphanumeric encodings with configurable byte lengths (16-128 bytes, 128-1024 bits of entropy). Uses CSPRNG (PHP random_bytes) so the token cannot be predicted or forged.

When to use: The synchronizer token pattern (a hidden form field checked against a session value), the double-submit cookie pattern, custom anti-CSRF headers for AJAX and SPA requests, and testing CSRF protection. Frameworks generate these automatically - Laravel , Django csrfmiddlewaretoken, Rails authenticity_token - but you can use this tool for custom stacks, mock data, and security testing.

Example: 7cJSvenfOMacDa3KOdlfgahpxLzqfxKir0wVQerGgY0 (Base64URL, 32 bytes, 256 bits entropy)

Security/Important: A CSRF token must be unpredictable, tied to the user's session, and verified server-side on every state-changing request (POST/PUT/PATCH/DELETE). Use at least 32 bytes (256 bits). Compare tokens with a constant-time function to avoid timing attacks. Pair CSRF tokens with SameSite cookies for defense in depth. In production, let your framework generate and rotate tokens - this tool is ideal for custom implementations and testing.

Our CSRF token generator creates secure random anti-CSRF tokens that protect your forms and API requests from cross-site request forgery attacks. Generate a CSRF token in Base64URL, Base64, Hex, or Alphanumeric encoding with configurable byte lengths (16-128 bytes) using a cryptographically secure random number generator (CSPRNG). A CSRF token is an unpredictable value the server issues to a user and requires back on every state-changing request; because an attacker's malicious page cannot read or guess the token, forged requests are rejected. Perfect for the synchronizer token pattern, double-submit cookie defenses, custom anti-CSRF headers in single-page apps, and testing CSRF protection. Frameworks like Laravel, Django, Rails, and Express generate tokens automatically, but this tool is ideal for custom authentication stacks and security testing. Related tools: a session secret generator for signing the session that anchors your token, an API key generator, and a bearer token generator. All tokens use CSPRNG for maximum unpredictability.

What is a CSRF Token Generator?

A CSRF token generator creates the random, unpredictable value used to defend against cross-site request forgery - an attack where a malicious site tricks a logged-in user's browser into sending an unwanted state-changing request to your application. Because the browser automatically attaches the user's session cookie, the forged request looks authentic. A CSRF token stops this: the server issues a secret token tied to the user's session and requires it back on every state-changing request, either as a hidden form field or a custom header. The attacker's page cannot read the token (the same-origin policy blocks it) and cannot guess it (it is high-entropy), so forged requests fail validation. Our generator uses a cryptographically secure random number generator (CSPRNG via PHP's random_bytes) so tokens are impossible to predict.

Two patterns dominate. In the synchronizer token pattern, the server stores the token in the user's session and embeds a copy in each form; on submission it compares the two. In the double-submit cookie pattern, the token is sent both as a cookie and as a request parameter/header, and the server checks that they match - useful for stateless or SPA architectures. Either way the token must be unpredictable (at least 32 bytes of CSPRNG randomness), bound to the specific user session, verified server-side, and compared in constant time. Modern frameworks - Laravel's , Django's csrfmiddlewaretoken, Rails' authenticity_token, Express with csurf - handle this automatically, but this tool lets you generate tokens for custom implementations, mock data, and testing.

CSRF Token Generator Configuration

Count (1-50 Tokens)

Specify how many CSRF tokens to generate (maximum 50). Each token is cryptographically unique using PHP's random_bytes function (CSPRNG). Generating several at once is useful for creating test fixtures, seeding mock sessions, or load testing form submissions and API endpoints.

Byte Length (16-128 bytes)

Control token entropy by selecting byte length before encoding. 16 bytes (128 bits) is the minimum, 32 bytes (256 bits) is recommended for CSRF protection, and 64 bytes (512 bits) offers extra margin. Higher entropy makes the token infeasible to guess or brute-force within a session's lifetime.

Encoding Format

Choose output encoding: Base64URL (URL-safe, no + / = characters - ideal for hidden fields, cookies, and headers), Base64 (traditional), Hex (lowercase hexadecimal), or Alphanumeric (0-9, a-z, A-Z only). Base64URL is a safe default because it embeds cleanly in HTML attributes, cookies, and HTTP headers without escaping.

How to Generate a CSRF Token

[STEP 1] Choose Length and Format

Select 32 bytes (256 bits) for solid CSRF protection and pick an encoding - Base64URL is a safe default for hidden fields, cookies, and headers. Use 64 bytes if you want extra entropy.

[STEP 1] Generate the Token

Click EXECUTE GENERATION to create CSRF tokens with CSPRNG security. Each token displays with a Copy button and shows its byte length, entropy bits, and strength assessment. All tokens use PHP's random_bytes for cryptographic randomness.

[STEP 1] Store It in the Session and Embed It

Store the token in the user's server-side session. Embed a copy in each form as a hidden field (for example <input type="hidden" name="csrf_token" value="...">) or expose it to your SPA to send as a custom header such as X-CSRF-Token.

[STEP 1] Verify on Every State-Changing Request

On each POST/PUT/PATCH/DELETE, compare the submitted token to the session token using a constant-time comparison. Reject the request if they do not match. Regenerate the token on login and privilege changes to prevent fixation.

CSRF Token Best Practices

_ High Entropy - Use at least 32 bytes (256 bits) of CSPRNG randomness so the token cannot be guessed or brute-forced within a session. Our generator uses PHP's random_bytes to guarantee unpredictability. Avoid predictable values like timestamps, counters, or user IDs.
_ Bind the Token to the Session - A CSRF token must be tied to the specific user session, not shared globally. Store it server-side (synchronizer token pattern) or as a per-session cookie (double-submit pattern) and reject tokens that do not belong to the current session.
_ Verify Every State-Changing Request - Validate the token on all POST/PUT/PATCH/DELETE requests. Safe methods (GET/HEAD) should never change state, so they do not need a token - but never perform mutations on a GET request in the first place.
_ Constant-Time Comparison - Compare the submitted token to the expected value with a constant-time function (hash_equals in PHP, crypto.timingSafeEqual in Node) to avoid timing side-channels that could leak the token byte by byte.
_ Combine with SameSite Cookies - Set session cookies to SameSite=Lax or Strict so browsers do not send them on cross-site requests, adding a second layer of CSRF defense. SameSite and CSRF tokens together provide robust protection.
_ Rotate on Login - Regenerate the CSRF token when the user authenticates or their privileges change, preventing session-fixation-style attacks where an attacker plants a known token before login.

Technical Implementation

Our CSRF token generator uses PHP's random_bytes (CSPRNG) ensuring cryptographic randomness, then encodes the bytes in your chosen format:

// CSRF Token Generation Algorithm
Algorithm: Cryptographically Secure Random Token Generation

// Step 1: Generate Random Bytes
byte_length = 32 (configurable: 16-128 bytes)
random_bytes = random_bytes(byte_length) // PHP CSPRNG
// Example: 32 bytes = 256 bits of entropy

// Step 2: Encode Based on Format
if (format == "base64url") then:
  token = base64_encode(random_bytes)
  token = strtr(token, '+/', '-_') // URL-safe chars
  token = rtrim(token, '=') // Remove padding

else if (format == "base64") then:
  token = base64_encode(random_bytes)

else if (format == "hex") then:
  token = bin2hex(random_bytes)

// Step 3: Synchronizer Token Pattern
// Server: session['csrf_token'] = token
// Form:   
// Verify: hash_equals(session['csrf_token'], request['csrf_token'])
//         // constant-time comparison

API Access for Developers

Generate CSRF tokens programmatically using our free REST API. Specify count, byte length, and encoding format for test fixtures, mock sessions, and automated security testing.

GET https://generate-random.org/api/v1/generate/csrf-tokens?count=5&length=32&format=base64url

VIEW FULL API DOCUMENTATION →

Frequently Asked Questions

What is a CSRF token and how does it work?

A CSRF token is a secret, unpredictable value the server issues to a user and requires back on every state-changing request. Because a malicious cross-site page cannot read the token (same-origin policy) or guess it (high entropy), forged requests lack a valid token and are rejected. The server compares the submitted token to the one stored in the user's session; if they match, the request is genuine. This defeats cross-site request forgery, where an attacker abuses the browser's automatic cookie sending.

How long should a CSRF token be?

Use at least 32 bytes (256 bits) of CSPRNG randomness. That is far beyond brute-force within any realistic session lifetime (256 bits is about 1.2x10^77 possibilities). Shorter tokens (16 bytes / 128 bits) are acceptable minimums, but 32 bytes is the recommended default. Avoid predictable schemes - the entire defense relies on the attacker being unable to guess the value.

What is the difference between the synchronizer token and double-submit cookie patterns?

In the synchronizer token pattern, the server stores the token in the user's session and embeds a copy in each form, then compares the two on submission - stateful but very robust. In the double-submit cookie pattern, the token is sent both as a cookie and as a request parameter or header, and the server checks they match - stateless and convenient for SPAs and APIs, though it requires care with cookie scoping. Both need a high-entropy, session-bound token like this generator produces.

Do I need CSRF tokens if I use JWT or bearer tokens in headers?

If your API is authenticated purely by a token sent in an Authorization header (not by a cookie), it is largely immune to classic CSRF, because the browser does not attach Authorization headers automatically to cross-site requests. CSRF protection is essential whenever authentication relies on cookies. Many apps use both - cookie sessions for the web UI (needs CSRF tokens) and bearer tokens for the API. Setting SameSite cookies adds further protection.

Where should I store the CSRF token?

Store the authoritative copy in the user's server-side session (synchronizer pattern) or in a dedicated cookie (double-submit pattern). Embed a copy in forms as a hidden field, or expose it to your front-end to send as a custom header like X-CSRF-Token. Never rely on a token that lives only in a place the attacker's page could read cross-origin, and always verify server-side.

Does my framework already generate CSRF tokens?

Yes - most do. Laravel provides the Blade directive and VerifyCsrfToken middleware, Django uses {% csrf_token %} and csrfmiddlewaretoken, Rails uses authenticity_token, and Express can use the csurf middleware. Use the framework's built-in protection in production; this generator is for custom stacks, understanding how tokens look, generating mock/test data, and security testing.

[ HOW TO CITE THIS PAGE ]

APA Style:
Generate-Random.org. (2026). CSRF Token Generator. Retrieved from https://generate-random.org/csrf-tokens

Web Citation:
CSRF Token Generator - Generate-Random.org (https://generate-random.org/csrf-tokens)