serverpod/serverpod-models

Serverpod Models

Models are defined in .spy.yaml files anywhere under server lib/. They generate Dart classes for server and client, and optionally database tables.

After each change to models, ensure that the code is generated (automatically when a serverpod start is running or manually with serverpod generate). If models with table have changed, the database schema must be updated following the migration workflow.

Basic class

class: Company
fields:
  name: String
  foundedDate: DateTime?
  employees: List<Employee>

Field types: bool, int, double, String, Duration, DateTime, ByteData, UuidValue, Uri, BigInt, generated classes/enums/exceptions, List<T>, Map<K,V>, Set<T>, Record. Use ? for nullable.

Required fields

class: Person
fields:
  name: String
  nickname: String?, required

Database table

Add table for a database table + ORM:

class: Company
table: company
fields:
  name: String
  foundedDate: DateTime?

Scope

• Server-only class: serverOnly: true
• Per-field: scope=serverOnly, scope=none (default all)
• Non-persisted field: !persist (not stored in DB)
• JSON key alias: jsonKey=display_name

Immutable classes

immutable: true — final fields, ==, hashCode, copyWith.

Inheritance

• extends: ParentClass — child inherits parent fields. Only one class in hierarchy has table.
• sealed: true — abstract sealed hierarchy for exhaustive subtypes. No table on sealed class.

If parent is serverOnly, children must be too. Children cannot redefine parent fields.

Enums

enum: Status
values:
  - pending
  - active
  - completed

Default serialization: byName. Set serialized: byIndex to use index.

Exceptions

Use exception: instead of class: for serializable exceptions. Same field types as classes; supports default and defaultModel. Uncaught exceptions become generic 500 errors on the client; only serializable exceptions send their data.

exception: MyException
fields:
  message: String
  errorType: MyEnum

Throw on server, catch on client:

// Server
throw MyException(message: 'Failed', errorType: MyEnum.thingyError);

// Client
try {
  await client.example.doThingy();
} on MyException catch (e) {
  print(e.message);
}

Serializable exceptions can also be sent over streams (both directions; the stream closes after). Do not put sensitive data in exception fields — they are sent to the client.

Indexes

indexes:
  company_name_idx:
    fields: name
    unique: true

Relations

One-to-one (FK with unique index):

• ID field: addressId: int, relation(parent=address) + unique index on addressId
• Object field: address: Address?, relation (generates addressId)
• Optional: relation(optional) for nullable FK; relation(field=customId) for custom FK name
• Bidirectional: same relation(name=...) on both sides, field= on FK side

One-to-many:

• "One" side: employees: List<Employee>?, relation
• "Many" side: companyId: int, relation(parent=company) (no unique index)
• Bidirectional: relation(name=company_employees) on both sides

Many-to-many: Use a join table model with two relation fields.

Querying: include for eager loading, includeList with where/orderBy/limit/offset for list relations. attach/detach for managing relations.

Client-side database

Models with the table keyword can also generate a client-side database with the database keyword:

class: Company
table: company
database: client

| Value | Description | | ------- | ----------- | | server | Generates tables only on the server, and a non-table model on the client package (default). | | client | Generates tables only on the client, and a non-table model on the server package. | | all | Generates table models on both server and client. |

For how to use the client-side database, see the Serverpod Database skill.

Backward compatibility

To keep backward compatibility, do not change or remove fields in serialized classes used by clients. Add new fields only if nullable or with a default value, so older clients that don't send the field still work.

Custom serialization

To use serializable models not in YAML: implement toJson(), fromJson, copyWith(). Register in config/generator.yaml under extraClasses with full URI (e.g. package:my_shared/my_shared.dart:ClassName). Both server and client must depend on the package. Freezed classes with fromJson work the same way. Implement ProtocolSerialization with toJsonForProtocol() to omit fields when sending to client.