数据库：以托管 PostgreSQL 作为大多数 SaaS 的起点

Recommendation

多数 SaaS 从托管 PostgreSQL 起步；需要一体化后端时看 Supabase，需要弹性分支工作流时看 Neon。

先选择关系模型与事务边界；实时、认证、分支或边缘部署是随后才需要的条件。¹ ²

Main trade-off

专用数据库服务通常更易运营，但会在网络、扩展方式和迁移路径上形成约束。¹ ³ ⁵ ⁷

选择标准

从数据模型、运维责任与平台边界出发判断。

Data shape and access
Model relationships, aggregates, key lookups, write paths, and the queries the product must answer.⁷
Integrity and consistency
Declare transaction boundaries, constraints, write visibility, and acceptable stale or conflicting state.¹ ²
Durability and recovery
Set backup, restore, point-in-time recovery, availability, and geographic requirements before comparing services.¹ ²
Ownership and portability
Decide whether an engine, an integrated backend, or a runtime-native database is the intended long-term boundary.³

适用路线

按实际工作负载与系统边界选择替代方案。

You want one integrated backend

Evaluate Supabase.

PostgreSQL, Auth, Storage, Realtime, APIs, and policy tooling can remove substantial assembly work for a small team.

Verify: Treat this as a platform decision; independently replaceable identity, storage, API, and database boundaries point elsewhere.¹ ² ³

You want focused elastic PostgreSQL

Evaluate Neon.

It preserves a PostgreSQL-focused service boundary while adding branching and elastic compute.

Verify: Validate suspension, connections, recovery, region availability, capacity, and usage economics against the real workload.¹ ² ⁴

The application is intentionally Cloudflare-native

Evaluate Cloudflare D1.

Workers bindings and SQLite semantics can be a coherent fit for a platform-native application.

Verify: Do not use it when PostgreSQL compatibility, provider portability, or workload behavior outside D1's documented limits is required.¹ ² ⁵ ⁶

The domain is intrinsically document-shaped

Evaluate MongoDB.

Bounded aggregates can map naturally to documents when relationships and cross-aggregate transactions are not dominant.

Verify: Choosing documents merely to avoid schema design is not enough; relational integrity and SQL-shaped access should keep PostgreSQL in front.¹ ² ⁷

Boundary: This Task chooses the source-of-truth family. Managed PostgreSQL providers, serverless elasticity, ORMs, caches, lexical search, vector search, and file storage are separate downstream decisions.