TL;DR verdict
Choose Supabase for the default startup SaaS backend in 2026 when you want Postgres, SQL migrations, predictable team workflows, auth, storage, realtime, and a clear path from local Docker development to production. Choose Firebase when your product is mobile-first, document-shaped, event-heavy, or already committed to Google's Firebase ecosystem. Choose AWS Amplify Gen 2 when your startup is AWS-first, needs Cognito/AppSync/S3/Lambda integration, or wants TypeScript-defined backend resources that map directly to AWS infrastructure.
The Search Console opportunity for this page is not a generic BaaS popularity query. It is startup decision intent plus practical Amplify Gen 2 questions around sandbox workflow, local emulator expectations, Lambda functions, and allow.group authorization rules. This refresh keeps the startup backend-platform comparison as the page's center of gravity while adding the practical Amplify details founders and engineers are actually searching for.
Prices and plan names change, and quotas and product capabilities can change too. The official sources in this guide were checked on 2026-05-15; verify current vendor documentation and pricing before committing a launch architecture or promising a customer-specific backend capability.
Key Takeaways
- Supabase is the safest default for most web SaaS starters because the product model usually wants relational data, SQL migrations, tenant/team tables, billing records, and Postgres-compatible reporting.
- Firebase is still excellent for mobile-style and event-style apps where Firestore documents, offline sync, Firebase Auth, Cloud Functions, and the Emulator Suite fit the product better than relational schema design.
- Amplify Gen 2 is no longer the old Amplify CLI story. It is TypeScript-defined infrastructure that provisions real AWS resources through sandbox and deployment workflows; that is powerful, but it also makes AWS literacy part of the startup's operating model.
- Local development is the biggest practical split: Supabase runs a local Docker stack, Firebase has a broad local Emulator Suite, and Amplify Gen 2 leans on cloud sandboxes rather than a full local clone of Cognito, AppSync, DynamoDB, S3, and Lambda.
- Subscriptions and billing still belong in your app. None of these platforms replaces Stripe, Polar, Paddle, or Lemon Squeezy entitlement modeling, webhook idempotency, plan downgrades, or seat reconciliation.
- Lock-in is not only vendor lock-in. A Firestore document model, DynamoDB access-pattern design, or Postgres RLS policy set can all create switching cost. The best startup choice is the one whose constraints match your first 18 months.
At-a-glance startup backend matrix
| Startup decision | Supabase | Firebase | Amplify Gen 2 | StarterPick recommendation |
|---|---|---|---|---|
| Fastest web SaaS MVP | Strong: Postgres, Auth, Storage, Realtime, Edge Functions, SQL migrations. | Strong if the data is document-shaped and you already know Firebase. | Strong if the team knows AWS and accepts cloud sandbox workflow. | Start with Supabase unless mobile-first or AWS-first requirements are already real. |
| Auth and teams | Supabase Auth plus Postgres RLS; app still owns tenant and billing policy. | Firebase Auth is mature; authorization rules and Firestore structure need careful review. | Cognito-backed auth plus Gen 2 authorization rules in TypeScript. | Pick the model your team can test server-side, not just the prettiest sign-in screen. |
| Realtime | Postgres-backed realtime channels for table changes and broadcasts. | Firestore listeners and Realtime Database patterns are mature. | AppSync GraphQL subscriptions fit AWS-native realtime needs. | Supabase for relational SaaS events; Firebase for mobile sync; Amplify for GraphQL/AWS stacks. |
| Subscriptions and billing | App-owned billing tables alongside Postgres domain data are straightforward. | Billing state must be modeled around documents and Cloud Functions. | Billing state usually lands in DynamoDB/RDS plus Lambda/EventBridge-style workflows. | Keep Stripe/Polar/Paddle entitlement truth in your app regardless of provider. |
| Local development | Local Supabase CLI stack with Postgres, Auth, Storage, Realtime, Studio, and functions. | Emulator Suite for Auth, Firestore, Functions, Storage, Hosting, and UI inspection. | Personal cloud sandbox with real AWS resources; not a full local emulator suite. | Use Supabase/Firebase when offline/local repeatability matters; use Amplify when AWS fidelity matters more. |
| Lock-in and exit path | Lowest platform lock-in because Postgres and self-hosting are credible escape paths. | Higher data-model and SDK lock-in around Firestore documents and Firebase APIs. | AWS-service lock-in, but infrastructure primitives are standard AWS building blocks. | Score lock-in by data model, auth model, and developer operations, not slogans. |
| Launch speed | Usually fastest for Next.js SaaS boilerplates and SQL-first products. | Fast for apps that fit Firebase's client SDK and rules model. | Fast for AWS-aligned teams; slower for teams new to Cognito/AppSync/IAM. | The best launch stack is the one your team can debug under pressure. |
Evidence cards
Supabase evidence card
Supabase's official documentation and pricing position the platform as a Postgres-centered backend with local development tooling, Auth, Row Level Security, Realtime, Storage, Edge Functions, and plan-based hosted infrastructure. That combination maps cleanly to SaaS starter-kit work: tenants, teams, invoices, subscription rows, admin reporting, and SQL-based migrations all belong naturally in the same relational model.
Implementation read: Supabase is not automatically secure because it has RLS. A production starter must define and test policies for owner/admin/member roles, billing admins, service-role access, webhook writes, and background jobs. But the interface is deep for SaaS: one Postgres-backed seam can handle app data, policies, reporting, and migration history.
Firebase evidence card
Firebase's official Firestore and Emulator Suite documentation supports a different operating model: client SDKs, document collections, local emulators, Functions, Auth, and Google-managed scale. For mobile apps, collaborative lightweight state, prototypes, and products that naturally store nested documents, that can be the fastest path to a working product.
Implementation read: Firebase becomes expensive or awkward when a B2B SaaS product needs relational joins, ad hoc reporting, tenant-level billing queries, and migration discipline. The decision should be based on product shape, not age. Firebase remains strong where its document/offline/event model is the product fit.
Amplify Gen 2 evidence card
AWS Amplify Gen 2's official docs describe a code-first backend where data, auth, storage, and functions are defined in TypeScript and provisioned as AWS resources. The sandbox workflow creates a personal cloud backend for each developer, and authorization examples use TypeScript rules such as allow.group to express group-based access.
Implementation read: Amplify Gen 2 is a credible startup backend when AWS is the long-term home, but it is not a drop-in local Firebase emulator replacement. Founders should evaluate Cognito, AppSync, DynamoDB, S3, Lambda, IAM, and sandbox/deployment workflows as the actual implementation surface.
Launch stack table
| Launch layer | Supabase-first stack | Firebase-first stack | Amplify Gen 2-first stack | Required startup check |
|---|---|---|---|---|
| App database | Postgres tables, migrations, RLS policies, SQL reporting. | Firestore collections/documents, security rules, denormalized reads. | DynamoDB/AppSync model definitions, or AWS data services behind Amplify. | Write the first tenant/team/billing schema before picking the provider. |
| Auth | Supabase Auth with JWT claims and RLS policy integration. | Firebase Auth with rules and server-side verification where needed. | Cognito-backed Amplify Auth. | Test signed-out, member, admin, billing admin, suspended, and deleted-user states. |
| Realtime | Supabase Realtime channels over Postgres changes or broadcasts. | Firestore listeners or Realtime Database. | AppSync GraphQL subscriptions. | Simulate multi-tab/team updates and permission changes, not just happy-path messages. |
| Functions | Supabase Edge Functions for lightweight backend endpoints. | Cloud Functions for Firebase. | Lambda functions defined through Amplify. | Verify secrets, retries, logs, cold-start tolerance, and webhook idempotency. |
| File storage | Supabase Storage with policies. | Cloud Storage for Firebase. | S3 via Amplify Storage. | Test private files, signed URLs, tenant boundaries, and deletion on account closure. |
| Local/dev workflow | supabase start, migrations, local Studio, local functions. | firebase emulators:start, emulator UI, import/export where needed. | npx ampx sandbox with personal AWS cloud resources. | Decide whether local repeatability or cloud fidelity matters more to the team. |
| Deployment | Hosted Supabase project plus app hosting on Vercel/other. | Firebase projects plus app hosting/Cloud Functions as needed. | Amplify sandbox/promote/deploy workflows and AWS resource ownership. | Separate local, preview, staging, and production credentials. |
| Exit path | Standard Postgres dump/migration path is comparatively clear. | Export and transform document data; SDK/rules rewrite likely. | AWS resources are durable, but app code is coupled to AWS service interfaces. | Keep provider IDs as adapters; keep product domain IDs in your app. |
Billing and subscription ownership matrix
| Subscription/billing event | What the backend platform helps with | What your SaaS code must still own | Failure mode to test |
|---|---|---|---|
| Customer signs up | Auth identity, session, profile primitives. | Trial creation, default plan, subscription owner, workspace creation. | A user gets app access without a billing workspace or tenant record. |
| Team member invited | User identity and sometimes membership primitives. | Seat counting, invite expiry, role limits, paid-seat timing. | Charged seats do not match active members. |
| Plan upgraded | Database and function hooks can store/update state. | Entitlement truth, webhook idempotency, upgrade timing, invoice reconciliation. | Paid features unlock before payment succeeds or stay locked after upgrade. |
| Plan downgraded | Provider can host data but does not decide product policy. | Feature removal, data retention, usage limits, grace periods. | Enterprise features stay active after downgrade. |
| Usage-based billing | Events can be stored or processed. | Meter definition, event dedupe, reporting, customer-visible totals. | Duplicate events overcharge or missing events undercharge. |
| Account deleted | Auth provider can remove/disable user identity. | Data retention, subscription cancellation, audit history, workspace ownership. | Deleting auth breaks billing or leaves orphaned paid resources. |
The backend platform is infrastructure, not a subscription engine. A serious starter keeps billing and entitlement logic in app-owned code whether the user table lives next to Postgres RLS policies, Firestore documents, or AWS-backed data models.
Local development and emulator reality
Search demand around "Amplify Gen 2 local emulator" is easy to misread. Amplify Gen 2's core workflow is a cloud sandbox, not a complete local emulator suite. That is a valid engineering choice: you test against real AWS services in a developer-specific environment. It also means the team needs AWS credentials, cloud-resource hygiene, and a strategy for offline work.
# Supabase: local stack, Docker, migrations, local functions
supabase start
supabase db reset
supabase functions serve
# Firebase: local emulators and Emulator UI, commonly including localhost:4000
firebase emulators:start
# Amplify Gen 2: personal cloud sandbox using real AWS resources
npx ampx sandbox
For an early SaaS team, local development should be scored as an operational requirement:
| Requirement | Best fit | Why |
|---|---|---|
| Reproducible SQL schema in every PR | Supabase | Migration files and local Postgres make reviewable schema changes natural. |
| Broad local service emulation | Firebase | The Emulator Suite covers Auth, Firestore, Functions, Storage, Hosting, and more. |
| Highest fidelity to production AWS services | Amplify Gen 2 | Sandbox resources are real AWS resources rather than local mocks. |
| Offline-first development | Firebase or Supabase | Amplify sandbox needs cloud access for the normal workflow. |
| Debugging IAM/Cognito/AppSync/Lambda integration | Amplify Gen 2 | The cloud sandbox exposes the real seams you will deploy. |
Practical Amplify Gen 2 authorization notes
Do not rewrite this page around code snippets, but the query cluster does deserve one practical answer. Amplify Gen 2 authorization rules are defined in TypeScript near the data model. A typical group-based rule looks like this:
import { a, defineData, type ClientSchema } from '@aws-amplify/backend'
const schema = a.schema({
Project: a.model({
name: a.string().required(),
tenantId: a.string().required(),
}).authorization((allow) => [
allow.authenticated().to(['read']),
allow.group('Admins').to(['create', 'update', 'delete']),
]),
})
export type Schema = ClientSchema<typeof schema>
export const data = defineData({ schema })
That pattern is useful for SaaS starters because it keeps backend authorization in versioned TypeScript instead of scattered dashboard configuration. It is not enough by itself. You still need app-owned tenant checks, billing entitlement checks, audit logs, tests for role changes, and a safe migration path when the product moves beyond simple groups.
Use Amplify Gen 2 when the team wants TypeScript-defined AWS infrastructure. Do not choose it only because a snippet looks concise; choose it when Cognito, AppSync, DynamoDB/S3/Lambda, IAM, and cloud sandbox operations are acceptable day-two responsibilities.
Cost to customize
| Customization area | Supabase likely effort | Firebase likely effort | Amplify Gen 2 likely effort | Why it matters |
|---|---|---|---|---|
| Tenant/team data model | Low/medium | Medium/high | Medium/high | Relational tenant tables are simpler than retrofitting joins into documents or access-pattern tables. |
| Auth UI and sessions | Medium | Low/medium | Medium | Firebase and Amplify have mature identity primitives; SaaS roles still need app policy. |
| RLS/security rules | Medium | Medium | Medium | Every platform requires policy tests; the syntax differs, but the risk is the same. |
| Subscription/billing integration | Medium | Medium/high | Medium/high | Billing truth must stay app-owned and tied to your provider's data model carefully. |
| Local/preview environments | Low/medium | Low/medium | Medium/high | Supabase/Firebase have strong local workflows; Amplify requires cloud sandbox discipline. |
| Reporting/admin dashboards | Low | Medium/high | Medium/high | SQL makes ad hoc reporting and admin joins easier for most SaaS teams. |
| Migration away later | Low/medium | High | Medium/high | Postgres is easier to move; document and AWS-service models need more transformation. |
The cheapest platform is the one whose constraints you do not have to fight. If the product is a B2B SaaS with teams, subscriptions, invoices, and admin reporting, Supabase usually minimizes customization cost. If the product is mobile-first or AWS-first, Firebase or Amplify can be cheaper because they avoid fighting the team's actual operating environment.
Startup decision scorecard
| Dimension | Supabase | Firebase | Amplify Gen 2 | How to interpret the score |
|---|---|---|---|---|
| Web SaaS launch speed | 9 | 7 | 7 | Supabase fits the common Next.js SaaS starter shape with less data-model friction. |
| Mobile/offline fit | 6 | 9 | 7 | Firebase remains the cleanest fit for many mobile and offline-sync products. |
| AWS enterprise fit | 6 | 6 | 9 | Amplify wins when AWS governance, Cognito, IAM, and AppSync are strategic requirements. |
| Local development repeatability | 9 | 9 | 6 | Amplify sandbox favors cloud fidelity over full local emulation. |
| SQL/reporting flexibility | 9 | 4 | 5 | SaaS admin, billing, and analytics work often wants relational queries. |
| Vendor/data-model portability | 8 | 4 | 5 | Supabase's Postgres base is the more portable data layer; Firebase and AWS designs can still be extracted with planning. |
| Operational simplicity for a small team | 8 | 7 | 5 | Amplify's power includes AWS operational surface area. |
Use the scorecard to start a proof of concept, not to avoid one. Build the same vertical slice in two days: sign-up, create workspace, invite member, create billable record, update it realtime, upload a file, run one background function, and downgrade the subscription. The best provider is the one that makes that slice boring.
Methodology
This refresh used current primary sources retrieved on 2026-05-15: Supabase pricing, local-development, RLS, and Realtime documentation; Firebase pricing, Firestore, and Emulator Suite documentation; AWS Amplify Gen 2 quickstart, authorization, functions, and sandbox documentation; plus the Wave 5 GSC and route-health artifacts for page intent and route-contract context. The GSC evidence showed startup comparison intent and practical Amplify Gen 2 local/emulator and group-rule queries, so the page was refreshed as a decision guide with one focused practical section rather than converted into a narrow code-snippet page.
The scoring is implementation-oriented. A high score means the platform's documented product surface maps cleanly to the work a SaaS starter must ship: auth, tenant authorization, realtime updates, file storage, subscription ownership, preview/prod separation, local development, and migration discipline. It does not mean a provider is universally better for every startup.
Source-backed FAQ
Is Supabase better than Firebase and Amplify for SaaS startups?
For most web SaaS starters, yes: Supabase is usually the default because Postgres, SQL migrations, RLS, Auth, Storage, Realtime, and local development line up with teams, subscriptions, admin reporting, and billing records. Firebase can be better for mobile/offline/document-shaped products. Amplify Gen 2 can be better for AWS-first teams that want TypeScript-defined AWS infrastructure.
Does Amplify Gen 2 have a local emulator like Firebase?
Not in the same sense. Firebase's Emulator Suite is a broad local emulator workflow. Amplify Gen 2's normal development workflow is a personal cloud sandbox created with npx ampx sandbox, so you test against real AWS resources in an isolated dev environment. That improves AWS fidelity but requires cloud access and AWS operational awareness.
How should I think about Amplify allow.group rules?
Treat them as backend authorization rules, not as your complete SaaS policy. They are useful because they live in versioned TypeScript alongside the data model. You still need app-owned tenant IDs, subscription checks, billing entitlements, role-change tests, and logs for privileged actions.
Which option has the lowest lock-in?
Supabase usually has the lowest platform lock-in because the core database is Postgres and the stack is self-hostable. Firebase has higher lock-in through Firestore's document model, rules, and SDK patterns. Amplify Gen 2 locks you into AWS services, although those services are standard AWS primitives rather than a single opaque database.
Which option is cheapest?
It depends on usage shape. Supabase has plan-based hosted pricing and add-ons; Firebase and many AWS services are more pay-as-you-go. A startup with efficient Firestore usage can stay cheap, while one bad listener pattern can create cost surprises. Amplify can be inexpensive at low volume, but the real cost includes AWS architecture time. Always model your expected reads, writes, storage, bandwidth, function calls, and auth users from current vendor pricing pages.
Can I use these platforms with Stripe or another billing provider?
Yes. But treat Stripe, Polar, Paddle, Lemon Squeezy, or another billing system as a separate app-owned integration. The backend platform stores users and data; your application still owns subscription state, entitlements, usage meters, webhook retries, downgrades, cancellations, and audit history.
Related guides
- Supabase RLS guide for SaaS boilerplates — deeper tenant, teams, and billing-policy review for Supabase-first starters.
- Supabase vs Firebase vs Appwrite starter guide — adjacent BaaS comparison when Appwrite is on the shortlist.
- Convex vs Supabase vs Firebase — realtime/database decision context when Convex is an option.
- Neon vs Convex for SaaS starters — file-backed or serverless database alternatives for teams not choosing a full BaaS.
- Usage-based billing guide — subscription and metering decisions that should remain separate from auth provider records.
- SaaS boilerplate security checklist — policy, webhook, secret, and rate-limit checks before production.
- Best SaaS boilerplates with Supabase — starter-kit inventory when you decide Supabase is the right default.
- Next.js SaaS tech stack guide — wider stack decisions beyond the backend platform.
Source notes
- Supabase pricing page, retrieved 2026-05-15. Used for pricing freshness and hosted-plan caveats; verify current quotas before purchase or launch.
- Supabase local development documentation, retrieved 2026-05-15. Used for local CLI, Docker-stack, migration, and local-function workflow discussion.
- Supabase Row Level Security documentation, retrieved 2026-05-15. Used for auth/RLS implementation caveats.
- Supabase Realtime documentation, retrieved 2026-05-15. Used for realtime capability positioning.
- Firebase pricing page, retrieved 2026-05-15. Used for pricing freshness and pay-as-you-go caveats; verify current rates before launch.
- Firebase Emulator Suite documentation, retrieved 2026-05-15. Used for local emulator and Emulator UI discussion.
- Cloud Firestore documentation, retrieved 2026-05-15. Used for document-database positioning and data-model caveats.
- AWS Amplify Gen 2 quickstart documentation, retrieved 2026-05-15. Used for TypeScript-first backend and AWS-resource workflow positioning.
- AWS Amplify authorization documentation, retrieved 2026-05-15. Used for
allow.groupand authorization-rule discussion. - AWS Amplify functions documentation, retrieved 2026-05-15. Used for Lambda/function implementation context.
- AWS Amplify sandbox documentation, retrieved 2026-05-15. Used for cloud sandbox versus local emulator framing.
- Wave 5 route-health artifact, retrieved 2026-05-15. Used for canonical public/raw route contract and the note that
localhost:4000is a Firebase emulator reference, not preview-host leakage.