Can MCP safely expose write operations

Picking the right protocol for your app

Ever tried to log into a work app and got hit with that old-school, clunky redirect page? Yeah, that's usually SAML (Security Assertion Markup Language) doing its thing in the background, probably keeping some enterprise server from 2010 alive.

Picking a protocol isn't just about what is "cool"—it's about who is using your app and what tech stack you're stuck with. If you're building a modern React app, you'll want something that doesn't make you want to pull your hair out over XML parsing.

Honestly, "better" is a trap. It's more about the right tool for the job. Here is how I usually break it down when I'm starting a new project:

• SAML (Security Assertion Markup Language): This is the "granddaddy" of sso. It uses XML to pass data between the identity provider and your app. You’ll see this a lot in finance or healthcare because big corporations have used it for decades. It’s rock solid but, man, it’s heavy and a bit of a pain to debug.
• OIDC (OpenID Connect): Think of this as a thin layer on top of OAuth 2.0 that uses JWT (JSON Web Tokens)—basically a compact way to send claims between parties. It uses JSON and is way friendlier for web and mobile devs. If you're building a retail app or something for a startup, oidc is usually the way to go because it handles apis and mobile apps way better than saml ever could.
• The "Who" Factor: If your customers are huge banks or use enterprise IDPs like Microsoft Azure AD, they might force you to use saml to bridge the gap with their legacy systems. If you're building a consumer app where people login with Google, you're using oidc.

I’ve seen teams try to force saml into a native mobile app and it’s always a nightmare. If you have the choice, go oidc. It's just cleaner and fits better into a modern CI/CD (Continuous Integration/Continuous Deployment) pipeline where you're shipping code fast.

Now that we've picked a "language" for our identity to speak, we gotta talk about how to actually keep those sessions secure without annoying the users.

Security first configurations you cant ignore

So, you got your protocol picked out. Great. But honestly? That is the easy part. The real headache starts when you have to figure out how to stop someone from stealing a session and camping out in your app forever.

I've seen so many devs just set a jwt to expire in thirty days because "it makes the ux smoother." Please, don't do that. If that token gets leaked, an attacker has a month-long pass to do whatever they want.

• Short-lived access tokens: Keep these tight—like 5 to 15 minutes tight. If it's a high-security thing like a finance dashboard, maybe even shorter.
• Refresh tokens are your bff: Use these to get new access tokens without bugging the user to login again. But, you gotta store them safely. Don't just leave them in the browser; use Refresh Token Rotation (where every time you use a token, you get a brand new one and the old one is killed) or keep them in a secure backend-only session.
• The cookie vs localstorage debate: Stop putting tokens in localstorage. Just stop. It’s vulnerable to XSS (Cross-Site Scripting) attacks where a hacker injects malicious scripts into your site. Use httpOnly and Secure cookies so javascript can't even touch them.

A 2023 data breach report by Verizon pointed out that stolen credentials are still the top way bad actors get in, so don't make it easy for them by leaving long-lived tokens lying around.

Multi-factor authentication (mfa) shouldn't be optional anymore. If you are building a healthcare app handling patient records, mfa is basically the law. But even for a simple retail site, it saves so much trouble.

Sometimes you don't want to nag users every single time they click a button. That is where step-up authentication comes in. Let them browse with a regular sso session, but if they try to change their password or delete their account? Boom—hit them with a TOTP (Time-based One-Time Password)—you know, those six-digit codes from an app—or biometrics check right then and there.

It’s all about balancing "don't annoy the user" with "don't let the hackers win."

Now that we've locked down the tokens and added some extra locks on the door, we need to talk about the user experience side of things—because if it's too hard to use, people just won't.

Improving the digital experience for customers

Ever wonder why users drop off right at the finish line? Most of the time, it’s because they hit a login wall that feels like a DMV interrogation.

If you make someone fill out a twelve-field form just to buy a pair of socks or check a medical test result, they're gone. sso isn't just a security thing—it's the secret sauce for a smooth user journey.

Managing multiple identity providers (idps) is a massive headache if you try to build it from scratch. I’ve seen teams waste months trying to support Google, Microsoft, and Okta all at once. Using a tool like SSOJet lets you plug in these connections without rewriting your auth logic every single time.

• One-click onboarding: Instead of making users verify an email and create yet another password, they just click "Sign in with Google." It's faster for them and cleaner for your database.
• Unified user profiles: You get to centralize user data in one spot. This means you don't lose your mind trying to sync user IDs across different platforms in a retail or b2b setup.
• Reduced friction: By removing the "forgot password" dance, you keep people in the flow of your app.

A 2023 report by Baymard Institute shows that nearly 25% of users abandon their carts because the site forced them to create an account. sso basically kills that problem by making "creating an account" happen in the background.

It’s about making the tech invisible. When you centralize everything, your devs can actually focus on building features instead of debugging login redirects.

Now that we’ve made it easy to get in, we need to make sure we have a clean way to end the session so users aren't left logged in on a public computer.

Handling the tricky parts of session management

Ever had that awkward moment where you log out of your email, but your calendar and docs are still wide open? Yeah, that is the "zombie session" problem and it's a huge pain for security.

Managing sessions across multiple apps is like trying to herd cats. If you're building a healthcare portal where privacy is everything, you can't just hope the user closes their browser. You need a solid plan for when they hit that "exit" button.

Getting one app to tell another app "hey, this guy is done" is surprisingly hard. You generally have two ways to handle this in oidc or saml setups:

• Front-channel logout: This uses the browser (like an invisible iframe or a redirect) to ping all the apps. It’s easy to set up but if a user closes their laptop halfway through, some apps stay logged in. Not great for a finance app.
• Back-channel logout: This is much more reliable. The identity provider talks directly to your server over an api. It's way more secure because it doesn't rely on the user's flaky chrome browser, but it requires your app to maintain a session store it can actually clear on demand.

According to a report by Cloudflare, session hijacking is a major risk when apps don't sync their logout states properly—basically leaving a back door wide open.

You also gotta think about session timeouts. If someone is using a retail kiosk, you want that session to die fast. If they're on a private dev machine, maybe give them more slack. Just don't let sessions live forever.

Now that we've figured out how to kick people out, we need to focus on how to monitor the whole system to make sure it's actually healthy and secure.

Testing and auditing your sso setup

Building a sso system and just walking away is like leaving your front door unlocked because you "trust the neighborhood." You gotta watch the logs, or you're gonna have a bad time.

Honestly, most devs forget that identity is a moving target. What worked during your sprint demo might break when a real user tries to login from a weird vpn in another country.

Setting up alerts for weird login patterns is basically mandatory. If you see 500 failed attempts from one ip in a minute, that’s not a forgetful user—it’s a brute force attack.

• Watch the spikes: Use your logs to see why people can't get in. Is it a broken redirect or a legit security threat?
• Audit access regularly: In finance or healthcare apps, you need to know exactly which third-party tools still have access to your user data.
• Debug with logs: When a user says "it's broken," your first stop should be the correlation id. This is just a unique string (like a UUID) that gets passed through the whole auth flow so you can track a single request across all your different services and see exactly where it died.

As mentioned earlier in the Verizon report, stolen credentials are a massive risk, so catching a credential stuffing attack early is your best defense.

Implementing sso is a journey, not a one-time ticket. Keep testing, keep auditing, and stay safe out there.