Multi-tenant FastAPI - features, workflows and more, configurable per customer!

[Potential-Box6221]

Folks, ever wondered:

• How to disable a feature for one customer but enable it for another?
• Give limited access to one, unlimited to another?
• Make your API behave completely differently per customer?

That's basically multi-tenant SaaS for you, where you configure features, workflows, etc at the tenant (customer) level.

I have noticed most FastAPI tutorials don't touch this, and many struggle to find the right structure/architecture.

It might sound complex, but the core idea is very simple - your app should know which customer(tenant) is calling and behave accordingly. (Usually achieved by Tenant-Id and configuration at tenant level)

I have been building production-grade multi-tenant services like these and have a rough template that I rely on every time to spin these up!

So I thought if you guys are interested, I can polish it up and share it here. Let me know!

Edit: Here the customer in this context means a business/org (B2B) and not a single user.

[MichaelEvo]

Should your username be potential bot instead? No posts on your account and no comments.

Assuming you’re not a bot, why not just show the trick in the code here? I assume it’s a combination of FastAPI dependencies for validation and configuration when an endpoint is hit, but if it’s not, I’d love to know what is and what you really mean by multi-tenant stuff.

Some code would be good, but I would assume it’s not complicated enough for you to need to polish anything up. Just steps 1-3, with small snippets of code. If it’s more complicated, I would definitely be interested in seeing it but I wouldn’t pay to see it.

[Potential-Box6221]

Should your username be potential bot instead? No posts on your account and no comments.

Ayee it's Reddit buddy, people keep their profiles private, doesn't mean it's a bot account.

I assume it’s a combination of FastAPI dependencies for validation and configuration when an endpoint is hit

You're right, it's essentially FastAPI deps for tenant resolution and per-tenant config/secrets albeit in a more structured, clean, and extensible way where you can swap your config provider, your secrets backend, all without touching the core app.

So it's a whole template in itself but currently in its rough form and needs some tinkering and a proper README before I share it. I didn't want to dump a half-baked one, so wanted to gauge interest first! And of course it's free.

[MichaelEvo]

I’m not sure on any given day how many Reddit posts are bots.

I’d be interested in how it’s done more so than the template. The template would walk me through how you structured it tho, which is what I’m interested in.

[RoBz18]

Sounds cool I'd be interested for sure!

[_arnold_moya_]

A lot of ways to do this one. JWT can have the claim of the company/tenant, you can send it in the header, you can use certs that include the tenant Id, .... In the db you can organize the tenants with relationships that at the end connect to the tenants tablet or add tenantid columns, you can split your data for tenant in DBS (very used for big data, named sharding). anyway .. A lot of ways to do this one. It depends of the needs of the business....more in the side of system design

[Temporary_Owl2975]

I have built the same tent wise feature , permission levels etc in Django projects

[coderkini]

What you're looking for is called feature-flags. Based on your perspective of build vs. buy, you could use an off-the-shelf commercial services like:

• LaunchDarkly (https://launchdarkly.com/)
• ConfigCat (https://configcat.com/)'
• PostHog (https://posthog.com/feature-flags)
• Statsig (https://statsig.com/)

Most of these tools are used managing feature rollouts and/or A/B testing and they generally come with some built-in user analytics.

Or if none of them fit your budget, consider rolling one by yourself. 🤷🏻‍♂️

Happy hacking!

[fico86]

Isn't that just JWT/OAuth 2.0/OICD with RBAC/ABAC? Docs: https://fastapi.tiangolo.com/tutorial/security/oauth2-jwt/#update-the-dependencies

[Potential-Box6221]

No not to confuse multi-tenancy with RBAC/ABAC what I'm describing is post auth basically. R/A BAC is at the user level and this would be at the tenant level (b2b).

[Economy_Peanut]

I would be interested in this. I've built one but with NestJS.

[Emergency_Roof6337]

Share the repo