Single Sign on Microservice
You build a single sign on microservice by putting user login into one service. This central app checks user credentials and issues signed tokens to your other apps. Teams often link this service to an external identity provider using standard web protocols. They map directory groups to broad app roles so staff can log in fast. When these roles are too wide, one login gives too much power across services. How a single sign on microservice works in practice In a split system, you do not want e
Single Sign-On (SSO): the complete guide
Architecture patterns, implementation strategies, and security best practices. Delivered to your inbox.
You build a single sign on microservice by putting user login into one service. This central app checks user credentials and issues signed tokens to your other apps. Teams often link this service to an external identity provider using standard web protocols. They map directory groups to broad app roles so staff can log in fast. When these roles are too wide, one login gives too much power across services.
How a single sign on microservice works in practice
In a split system, you do not want every small app storing user passwords. Instead, the single sign on microservice handles the login flow for the whole platform. When a user visits an internal app, that app sends them to the login service. The login service talks to your central identity provider to check who the user is. The identity provider checks the password and runs a second factor check if needed.
Once the check passes, the login service gets a message with the user identity. It reads the user group memberships and builds a signed token for the session. The user browser or client sends this token with each request to backend services. Each backend service checks the digital signature using a shared public key. If the signature is valid, the backend service trusts the user identity and role.
Managing tokens and roles across internal services
Teams must decide what data to put inside the signed session token. Putting every permission inside the token makes the token very large on every call. Keeping the token small means backend services must look up role rules on their own. Most teams put basic group names in the token and cache role rules locally.
Token lifetime is another key choice when you set up this login service. Short token lifetimes limit risk if an attacker steals a token from a device. Still, very short lifetimes force the client to ask for new tokens very often. Teams use refresh tokens so the login service can check if the user remains active. If an admin bans a user, the login service stops giving out new tokens.
Single Sign-On (SSO): architecture patterns and best practices
Continue reading? Get the full guide.
Free. No spam. Unsubscribe anytime.
What central login solves and what it misses
A central login service stops password reuse and makes user offboarding much faster. When a worker leaves the team, you disable their account in one single place. You also get one central log that shows every time someone logs in. App builders can focus on core features instead of writing custom login logic.
Still, this setup only checks who logs in at the start of a session. It does not inspect what individual queries, commands, or requests do in flight. Once an engineer or service holds a valid token, backend databases trust their broad role. A valid login token cannot stop a bad query from dropping a production table. It also does not rewrite sensitive fields like emails, phone numbers, or card numbers in results. To control live actions, teams must check and filter requests at the command level.
Check database and API queries on the wire
Identity tools, roles, and network rules decide who opens a session. Setup alone cannot check what each query does or mask sensitive values in a response once a session starts. When workflows touch Postgres, MySQL, SQL Server, MongoDB, ClickHouse, Kubernetes APIs, SSH, or internal HTTP APIs, hoop.dev runs beside those services as an open-source proxy, a sidecar for your Postgres or API. It inspects requests coming in and results going back on the wire.
Your login details and client tools stay as they are while hoop.dev guardrails refuse bad deletes or drops before they run. On responses, hoop.dev data masking rewrites matched sensitive values in memory. Furthermore, hoop.dev holds SOC 2 Type II, is MIT licensed, and writes every query and decision to an audit trail that generates evidence for HIPAA, GDPR, and PCI DSS. See the source on GitHub.
Frequently asked questions
How do backend apps check tokens without calling the login service every time?
The login service signs each token with a private key. Backend apps use a matching public key to check the signature locally in memory.
What happens if the central login service goes down?
Users with active tokens can keep working until those short tokens expire. New users cannot log in until the service comes back online, so teams run multiple copies.
Does single sign on protect sensitive data inside database queries?
No, single sign on only proves user identity at the start of a session. You need query inspection and data masking to rewrite emails or card numbers in results.