If you are anything like me, your brain is constantly thinking of new ideas and products to build. In the age of AI, its possible to create prototypes for these ideas in minutes or hours.
So when a new idea hits you, you don't want to chose the wrong database. Choosing the wrong database can have many negative implications. You might be making great progress, but then about 75% of the way complete you are hit with a blocker that requires a major schema refactor. Or worse, the database you chose actually cannot support a critical piece of the architecture and you are forced to start over.
I've built products that use Convex and products that use Supabase. I've made the mistakes I mentioned above so you don't have to.
Let's jump into it.
Realtime/Reactivity
I'm starting with realtime because this differentiation is so big to me. Convex offers realtime support out of the box. Meaning all of your tables will have realtime capabilities by default. This is huge.
I was in awe the first time I used Convex after building many apps with Supabase. The setup is crazy simple. I had realtime database changes on my client the second my convex tables were created. Without any additional code or configuration. Didn’t touch a dashboard. It was just working and the dev experience was incredible.
Supabase does offer realtime support, but it requires more setup and configuration. You have to enable it on each table that you would like realtime on via SQL query or manually in their dashboard.
The big kicker for me is the reactivity.
With Supabase, you will likely need to end up using some sort of state management library, such as Legend State, and react observables to reflect live database changes on the client.
With Convex, the queries are already reactive. So the client re-renders automatically when the data changes without any additional code. I cannot express how incredible this is from a DX perspective. If you want speed, you have it with Convex here.
Pricing
Big differences here. Supabase uses org bases pricing. Meaning, if you’ve got, say, 10+ projects on supabase and one needs to be on the paid plan then you’re paying $25/month for the initial org plan and $10 for each additional project in your org. This can add up incredibly fast since you only get 2 free projects and 1 free organization on the free plan.
Convex is the clear winner here. They have a generous free plan with 40 deployments included and 1-6 developer seats. When you are constantly creating new products and prototypes, you don't want to be charged $10 per new project.
SQL or No SQL?
Convex does not use SQL, while Supabase uses and is built around PostgreSQL.
If you are an experienced developer, chances are you know SQL. SQL is great for many things such as widespread standardization, ease of use, strong data integrity, and high performance. This also gives you flexibility in querying your database.
However, using SQL means your need to define and manage schemas. Removing or adding columns and keeping track of these changes can be a mess.
Convex uses a JSON-like document based storage. You might lose out on some query performance in large datasets, or might be forced to use a separate tool for a data warehouse.
In Convex, you don't have to manage a schema. Per Convex docs, it pairs with Typescript for schema inference and Typescript functions for schema generation. All of your tables and functions are managed in the same codebase you are building your product in with strong Typescript support. You need to add a column? Just write a new line of Typescript, save the file, and boom the table is updated with the new column. The simplicity here is hard to beat, and pairs well with vibe coding. No MCP tool calls are required, just Typescript.
Auth
In my opinion Supabase wins the battle here. They have extensive auth support and your first 100,000 MAUs are free. There are many social providers support as well. You can create custom emails and pretty much all other features a typical auth product would have are included with Supabase Auth. Supabase has built their product in a way that their auth feature integrates extremely easily with RLS policies and realtime. If you are going to use supabase, I'd suggest using their built in auth.
I have not tried Convex auth yet, but it is currently in Beta. In projects where I use Convex, I typically use Clerk for auth with their built in integration. They also have an integration with WorkOS. The integrations are pretty minimal.
Conclusion
I want to be clear that both are great for choices for modern web and mobile apps, but there are some key differences I will touched on above. You should pick what works best for your use cases and what you are comfortable with.
If you value speed and real time capabilities, then use Convex. This goes for chat and messaging apps, highly collaborative apps, and multiplayer apps.
Supabase is more well-suited for CRUD heavy apps, B2B multi-tenant apps, and analytics tools.
I hope this helps you make a decision and best of luck! Happy hacking!