Best AI app builder with backend: database, sign-in and storage compared

Best AI app builder with backend: what each one includes

Overskill is the pick here when you want the backend included in the plan fee. The database, file storage and sign-in behind an app come with 50 GB of database and 100 GB of files on both plans, and sign-in for your app's users and data reads and writes cost zero credits. Starter is $25 a month, billed monthly, in US dollars, as read on October 18, 2026.

Database and file storage limits

Overskill's allowances are 50 GB of database, up to 10 GB for any one app's database, and 100 GB of files. They are pooled across every app in the workspace, the account space that holds credits, apps and storage, and they are the same on both plans. Past the allowance, the database costs $1 per GB per month and files $0.05 per GB per month, charged from credits.

Overskill's pricing page promises a ZIP of code, database structure and data, and its export article adds a limit of 50,000 rows per table.

Lovable Cloud, its built-in hosting and backend, draws on the credit balance that also pays for building. Replit runs a managed PostgreSQL database, with a production storage cap of 100 GiB on paid plans and 1 GiB on Starter.

Sign-in for your app's users

Overskill adds sign-in for your users, with the methods you choose, and sign-ins cost zero credits. An SMS login code is a message and costs 1.6 credits. Built-in sign-in uses one shared Overskill account, so your users create or reuse an Overskill account, and Overskill branding stays on sign-in screens on every plan.

Lovable Cloud includes authentication, and Lovable's docs price the build step "add authentication" at 1.20 credits. Replit's default sign-in sends users through Replit accounts, with an option for accounts inside your own app. Base44 gives new apps login pages, and private apps need a paid plan.

Backend work that draws credits or hits a limit

• Overskill: email costs 0.1 credits per accepted send and a connected-service call about 0.5. At zero credits, live apps keep working while AI-powered changes stop.
• Lovable: Cloud, AI gateway and connector usage appear as Run credits, and its docs say backend services pause shortly after credits run out.
• Base44: built-in services such as email and LLM calls draw integration credits, and Base44 has no way to preview their cost before an action runs.
• Bolt (bolt.new): Bolt Cloud is the backend and hosting built into Bolt, and a site stops displaying at its plan's hosting limit until usage resets.

Who should pick which backend

Pick Overskill for a backend inside the plan fee, with sign-ins and data use outside the credit meter until storage passes the allowance. Pick Lovable to start on a free plan, which includes 20 Cloud credits a month, Base44 for built-in services metered in their own integration credits, and Replit if publishing costs from monthly credits suit you.

For a client portal, how to create a client portal covers sign-in and roles, and best AI app builder for non-coders adds the plain-English picks. Overskill pricing lists both plans; a new account starts with 500 credits, and Overskill lists no free plan.