At work: Head of Engineering 2026-now
One login for the whole platform
One login for every admin app and service; AI apps get in only after the user says yes.
Designed and built, alone, the one login for the whole platform: every admin app, every backend service, and outside AI apps like Claude and ChatGPT.
- Role
- Creator and sole developer
- Years
- 2026-now
- Scope
- Every admin app and backend service
- Used by
- Staff, customer users, AI apps
01 The problem
The company's admin apps live on separate web addresses, and the whole platform depends on knowing who a user is. Customers also wanted their own AI assistants to reach their business data, with clear limits and a fast way to cut access.
02 Result
- Staff and customer users sign in once for every admin app.
- Customers connect their own Claude or ChatGPT to their business data with only a web address.
- Each user can end AI access with one switch, or by signing out.
- A sign-out or a locked account takes effect on the next request.
03 What I built
- 01
Built from scratch
I wrote the design plan first, then built both parts alone: the login service and the login website people see.
- 02
One sign-in for all apps
People sign in once and reach every admin app, even ones on other web addresses. Every backend service asks it who a user is.
- 03
A permission for each action
Moved the whole platform from broad roles to one permission for each action, so access rules match in every service.
- 04
Consent screen for AI apps
Before an outside AI app connects, the user picks read or write access for each business area.
- 05
Users moved over
Moved user accounts out of the old admin system into the new login service, step by step.
- 06
Security fixes
Fixed weak spots that a security review found, such as two-step code guessing and faked visitor addresses, in small separate changes.
04 Risks I handled
- Risk 01
A stolen AI app key
A copied key could keep an AI app connected. Each use now gives a new key. If an old key comes back later, that whole connection and all its keys are cancelled at once.
- Risk 02
A sign-in code used twice
Two requests could bring the same one-time sign-in code at the same moment. Now each code works only once, even then, and expires quickly.
- Risk 03
A session used by another app
A review found that a sign-in session could be reused by a different app. Each session is now tied to the app that made it, which closed that path.
05 Stack
- Python
- FastAPI
- PostgreSQL
- Redis
- Next.js
- OpenID Connect
- OAuth 2
06 How it works
- 01An app sends the person to the login page.
- 02They sign in, with a two-step code if needed.
- 03The app gets a signed pass for that person.
- 04The platform's entry point checks the pass and permission on every call.
Get in touch.
Hiring an engineering lead, or building a platform or AI agents? Tell me about it.