SUBSTRIO VS. FIREBASE

Substrio vs. Firebase

Firebase gives you Google's app backend. Substrio adds email, maps, and a ledger, and every app you launch is ready for agents.

Unified apps

Build one app.Connect them all.

Every app you build on Substrio can work with every other one. Your users sign in once and move between your apps as the same person. One app uses another app's data and functions directly, with no HTTP and no shared code, and one agent works across all of them. You choose what each app shares.

One login across every app

Substrio: Built in

A person signs in once with Substrio, and every app connected to that sign-in lets them in without a password. Read the docs

Firebase: Partly built in

Apps in one Firebase project share sign-in. Separate projects have separate users.[3]

Apps that use each other

Substrio: Built in

One app can use another app's functions and queries directly, with no HTTP and no shared code. You choose what each app shares. Read the docs

Firebase: Not offered

Projects reach each other over HTTP, with credentials you manage.[2]

One agent across your apps

Substrio: Built in

An agent signs in once, at one app, and uses the tools of every app connected to it, as the same person. Read the docs

Firebase: Not offered

There is no MCP server for your users, so there is none to connect.[1]

Built for agents

Agents build it.Agents can use it.

Every app on Substrio is an MCP server. Your agent builds the app, and your users' agents can use it with the permissions of their login.

An MCP server in every app

Substrio: Built in

Every app you launch is an MCP server. Each route you write becomes a tool on the first deploy. Read the docs

Firebase: Not offered

The Firebase MCP server runs on a developer's computer and manages Firebase projects with the developer's Firebase sign-in.[1]

Your users' agents

Substrio: Built in

Your users connect their agents with OAuth or an agent token. Each agent works with that user's permissions and nothing more. Read the docs

Firebase: Not offered

There is no MCP server for your users.[1]

Your agent builds the whole app

Substrio: Built in

One connection gives your agent every operation, from data and functions to email, files, the site, and custom domains. Read the docs

Firebase: Partly built in

The MCP server covers Firebase projects, from a server on your computer. Email and maps are separate services.[1][2]

Sandbox, then go live

Substrio: Built in

Every version runs in a sandbox first. Going live backs up your data, and one call rolls back. Read the docs

Firebase: Partly built in

Hosting preview channels cover the site. A staging backend is a second Firebase project.[4][5]

Everything built in

Everything built in.Nothing to piece together.

Substrio includes every one of these services in one platform. Firebase includes 6 of the 17 capabilities on this page.

Database

Substrio: Built in

Collections you can query with SQL or JavaScript, on the same records. Read the docs

Firebase: Built in

Cloud Firestore.[2]

Sign-in and users

Substrio: Built in

Passwords, passkeys, email codes, eight sign-in providers, roles, and permissions. Read the docs

Firebase: Built in

Firebase Authentication.[2]

Email to your users

Substrio: Built in

Ready-made templates and one API call to send. Standard sends from your own domain. Read the docs

Firebase: Partly built in

Sign-in email only. Email from your app needs an outside provider, through the Trigger Email extension.[6]

Maps and geocoding

Substrio: Built in

Vector maps, address autocomplete, geocoding, and IP location. Read the docs

Firebase: Separate service

Google Maps Platform, billed separately.[7]

Functions

Substrio: Built in

Functions run beside your data, with routes, schedules, and triggers. Read the docs

Firebase: Built in

Cloud Functions for Firebase.[2]

Files

Substrio: Built in

File storage with public and private access. Read the docs

Firebase: Built in

Cloud Storage for Firebase.[2]

Realtime

Substrio: Built in

Realtime messages and live connections are part of every plan. Read the docs

Firebase: Built in

Realtime listeners in Firestore and the Realtime Database.[2]

Site hosting

Substrio: Built in

Your site launches at your-app.substrio.com on Free. Standard adds custom domains with TLS certificates. Read the docs

Firebase: Built in

Firebase Hosting, with custom domains.[2]

Ledger

Substrio: Built in

Balances and transfers are recorded in a built-in ledger. Read the docs

Firebase: Not offered

There is no ledger.[2]

One bill

One platform.One simple bill.

Egress costs $0 on every Substrio plan, and every service is part of one monthly price.

Egress

Substrio: Built in

Egress costs $0 on every plan. Read the docs

Firebase: Partly built in

Hosting egress past the daily allowance is billed at $0.15/GB.[8]

The same app costs $19/month on Substrio Pro and $685.88/month on Firebase and Google Maps. That's 36× the price.

The app: 10 GB of data, 50,000 users, 30,000 emails, and 250 GB of egress a month. Every price is a list price, checked on October 27, 2026.

See the Full Cost Breakdown

One platform.Every app connected.

Start free with no credit card and no time limit. Launch on Free, then grow with Standard for just $9/month.