Auth & Security

JWT Expiry Simulation & Renewal

Never wait 15 minutes to test your token expiration error handlers or silent background refresh routines. Request valid cryptographic JWTs with custom micro-lifespans (5s, 15s, 1m) or trigger already-expired tokens on demand.

Interactive Expiry Workbench

Choose a lifespan duration below to load into the console and test token invalidation:

Login with 5s Token Lifespan

POST

response.json

{

// Click "Send" above to execute this request against the live server.

}

Supported Expiry Modification Modalities

Playground API supports both header-based and request body configuration parameters:

Transport	Key / Field	Supported Syntax	Description
HTTP Header	X-Simulate-JWT-Expiry	"5s", "15s", "1m", "-1s"	Overrides access token lifespan without modifying request payload.
JSON Body	token_ttl	5, 10, 30, 60	Integer seconds defining precise token lifetime.
JSON Body	expiresIn / expires_in	"5s", "10m", "1h"	String duration format compatible with the `ms` library.

Auto-Refresh & Renewal Recipes

Frontend patterns for proactive silent token renewal before expiration occurs:

useAutoRefresh.ts

// React 19 Silent Auto-Refresh Pattern (Proactive Token Refresh)

import { useEffect, useRef } from 'react';

export function useSilentTokenRefresh(expiresInSeconds: number, onRefresh: () => Promise<void>) {

const timerRef = useRef<NodeJS.Timeout | null>(null);

useEffect(() => {

if (!expiresInSeconds || expiresInSeconds <= 0) return;

// Refresh 15% before actual expiry (e.g. at 4.2s for a 5s token)

const refreshBufferMs = Math.max(1000, expiresInSeconds * 1000 * 0.15);

const delayMs = expiresInSeconds * 1000 - refreshBufferMs;

timerRef.current = setTimeout(async () => {

try {

console.log('Initiating proactive silent token renewal before expiry...');

await onRefresh();

} catch (err) {

console.error('Silent refresh failed:', err);

}

}, Math.max(500, delayMs));

return () => {

if (timerRef.current) clearTimeout(timerRef.current);

};

}, [expiresInSeconds, onRefresh]);

}

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