Secure Cookies

Learn how to securely store Crossmint Auth cookies in your application

Authentication tokens are accessible to client-side JavaScript by default through non-HttpOnly cookies. For stronger security, you can store tokens in HttpOnly cookies, which are accessible only on the server side. This setup requires custom routes for refreshing tokens and logging out, using utilities from @crossmint/server-sdk.

1. Configure Cookie Options

When initializing the server SDK, configure secure cookie options:

import { createCrossmint, CrossmintAuth } from "@crossmint/server-sdk";

const crossmint = createCrossmint({ apiKey: process.env.SERVER_CROSSMINT_API_KEY });
const crossmintAuth = CrossmintAuth.from(crossmint, {
    cookieOptions: {
        httpOnly: true,
        secure: true, // Only send cookies over HTTPS
        domain: ".yourdomain.com", // Optional: specify cookie domain
    },
});

Note: The httpOnly flag only applies to the refresh token. The session JWT remains accessible to client-side JavaScript since it’s needed for API calls.

2. Custom Routes Implementation

Token Refresh Route

Next.js (App Router)

import { createCrossmint, CrossmintAuth } from "@crossmint/server-sdk";
import { NextRequest } from "next/server";

const crossmint = createCrossmint({ apiKey: process.env.SERVER_CROSSMINT_API_KEY! });
const crossmintAuth = CrossmintAuth.from(crossmint);

export async function POST(request: NextRequest) {
    return await crossmintAuth.handleCustomRefresh(request);
}

import { createCrossmint, CrossmintAuth } from "@crossmint/server-sdk";
import { NextRequest } from "next/server";

const crossmint = createCrossmint({ apiKey: process.env.SERVER_CROSSMINT_API_KEY! });
const crossmintAuth = CrossmintAuth.from(crossmint);

export async function POST(request: NextRequest) {
    return await crossmintAuth.handleCustomRefresh(request);
}

import express from "express";
import { createCrossmint, CrossmintAuth } from "@crossmint/server-sdk";

const app = express()
const crossmint = createCrossmint({ apiKey: process.env.SERVER_CROSSMINT_API_KEY! });
const crossmintAuth = CrossmintAuth.from(crossmint);

app.post("/api/auth/refresh", async (req, res) => {
    await crossmintAuth.handleCustomRefresh(req, res);
    res.end();
});

Logout Route

Next.js (App Router)

import { createCrossmint, CrossmintAuth } from "@crossmint/server-sdk";
import { NextRequest } from "next/server";

const crossmint = createCrossmint({ apiKey: process.env.SERVER_CROSSMINT_API_KEY! });
const crossmintAuth = CrossmintAuth.from(crossmint);

export async function POST(request: NextRequest) {
    return await crossmintAuth.logout(request);
}

import { createCrossmint, CrossmintAuth } from "@crossmint/server-sdk";
import { NextRequest } from "next/server";

const crossmint = createCrossmint({ apiKey: process.env.SERVER_CROSSMINT_API_KEY! });
const crossmintAuth = CrossmintAuth.from(crossmint);

export async function POST(request: NextRequest) {
    return await crossmintAuth.logout(request);
}

import express from "express";
import { createCrossmint, CrossmintAuth } from "@crossmint/server-sdk";

const app = express()
const crossmint = createCrossmint({ apiKey: process.env.SERVER_CROSSMINT_API_KEY! });
const crossmintAuth = CrossmintAuth.from(crossmint);

app.post("/api/auth/logout", async (req, res) => {
    await crossmintAuth.logout(req, res);
    res.end();
});

3. Client Configuration

Configure the client SDK to use your custom routes:

TypeScript

import { createCrossmint, CrossmintAuth } from "@crossmint/client-sdk-auth";

const crossmint = createCrossmint({ apiKey: process.env.NEXT_PUBLIC_CLIENT_CROSSMINT_API_KEY! });
const crossmintAuth = CrossmintAuth.from(crossmint, {
    refreshRoute: "/api/auth/refresh",
    logoutRoute: "/api/auth/logout"
});

import { createCrossmint, CrossmintAuth } from "@crossmint/client-sdk-auth";

const crossmint = createCrossmint({ apiKey: process.env.NEXT_PUBLIC_CLIENT_CROSSMINT_API_KEY! });
const crossmintAuth = CrossmintAuth.from(crossmint, {
    refreshRoute: "/api/auth/refresh",
    logoutRoute: "/api/auth/logout"
});

<CrossmintProvider apiKey={process.env.NEXT_PUBLIC_CLIENT_CROSSMINT_API_KEY ?? ""}>
    <CrossmintAuthProvider
        refreshRoute="/api/auth/refresh"
        logoutRoute="/api/auth/logout"
    >
        {children}
    </CrossmintAuthProvider>
</CrossmintProvider>

Note: Depending on the framework you’re using, you might need to set the whole URL in the refreshRoute and logoutRoute options.