Auth and identity · Comparison
Sessions vs JWT
Both keep a person signed in after they log in. A session keeps the facts on the server and gives the browser a random key; a JWT packs the facts into a signed token that the client carries around.
2 options · 8 questions side by side · updated
| Compare | Sessions | JWT |
|---|---|---|
| What the client holds | A random session ID in a cookie | A signed token with the user's details |
| Where the truth lives | A server-side store (database or Redis) | Inside the token itself |
| Checking a request | Look the ID up in the store | Verify the signature; no lookup needed |
| Signing someone out | Delete the record; works at once | Hard before expiry; needs short lifetimes or a deny list |
| Many servers | All must reach the same store | Any server with the key can verify |
| Size on each request | A short ID | Hundreds of bytes or more, growing with claims |
| Mobile apps and APIs | Possible, but cookies are awkward | A natural fit, sent as a bearer token |
| Watch out for | CSRF: use SameSite cookies and CSRF tokens | Theft through XSS if kept in localStorage |
How to choose between Sessions and JWT
- Pick sessions for a website or app with its own backend, where instant sign-out and simple revocation matter.
- Pick JWTs when several services or mobile clients must verify users without sharing a session store, and keep them short-lived.
- Many auth providers combine the two: a short-lived JWT for each request and a long-lived refresh token or session that issues new ones.
The options
- SessionsHow an app remembers that someone is signed in: the server keeps a record of the sign-in and gives the browser a random ID in a cookie, which comes back with every request.
- JWTA compact, signed token that carries facts about a user, such as their id and role, so a server can trust it by checking the signature instead of looking anything up.
More comparisons
- Magic link vs OTP vs passkeys vs social loginFour ways to let people in without asking them to invent a password. They differ in how many steps they take, what they cost to run and how well they stand up to phishing.
- Supabase Auth vs Firebase Auth vs Clerk vs Auth.js vs Auth0Five common ways to add sign-in without building it from scratch. Two come bundled with a backend platform, two are dedicated hosted services, and one is a library that runs inside your own app. MAU means monthly active users.
- Node.js vs Deno vs BunThree runtimes for JavaScript and TypeScript on the server. Much of the same code runs on all three; they differ in built-in tools, security defaults, speed and how long each has been used in production.
- Express vs Fastify vs HonoThree JavaScript web frameworks with a similar feel. Express is the long-standing default, Fastify focuses on throughput and structure, and Hono is built on web standards so it can run almost anywhere.
- FastAPI vs Django vs FlaskThree widely used Python web frameworks. Django includes almost everything, Flask includes almost nothing, and FastAPI focuses on typed, self-documenting APIs.
- REST vs GraphQL vs tRPC vs gRPCFour ways for apps and services to ask a backend for data. They differ in who can call them, how strictly the contract is typed, and what travels over the wire.
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