diff --git a/build.sbt b/build.sbt
index 135a09f..fcbf622 100644
--- a/build.sbt
+++ b/build.sbt
@@ -75,6 +75,7 @@ lazy val model = project
 
 lazy val db = project
   .in(file("modules/db"))
+  .dependsOn(model)
   .settings(sharedSettings)
   .settings(testSettings)
   .settings(name := s"${gsProjectName.value}-db")
@@ -86,6 +87,7 @@ lazy val db = project
 
 lazy val api = project
   .in(file("modules/api"))
+  .dependsOn(model, db)
   .settings(sharedSettings)
   .settings(testSettings)
   .settings(name := s"${gsProjectName.value}-api")
diff --git a/modules/db/src/main/scala/gs/smolban/db/DbError.scala b/modules/db/src/main/scala/gs/smolban/db/DbError.scala
new file mode 100644
index 0000000..5d3652c
--- /dev/null
+++ b/modules/db/src/main/scala/gs/smolban/db/DbError.scala
@@ -0,0 +1,20 @@
+package gs.smolban.db
+
+import gs.smolban.model.SmolbanError
+import gs.smolban.model.Ticket
+
+/** Parent type of all database errors in Smolban.
+  */
+sealed trait DbError extends SmolbanError
+
+object DbError:
+
+  /** Returned if an attempt is made to insert a [[Ticket]], where the Ticket ID
+    * already exists for the specified [[gs.smolban.model.Group]].
+    *
+    * @param ref
+    *   The Ticket Reference that was in conflict.
+    */
+  case class TicketAlreadyExists(ref: Ticket.Reference) extends DbError
+
+end DbError
diff --git a/modules/db/src/main/scala/gs/smolban/db/TicketDb.scala b/modules/db/src/main/scala/gs/smolban/db/TicketDb.scala
new file mode 100644
index 0000000..e636622
--- /dev/null
+++ b/modules/db/src/main/scala/gs/smolban/db/TicketDb.scala
@@ -0,0 +1,48 @@
+package gs.smolban.db
+
+import cats.data.EitherT
+import gs.smolban.model.Ticket
+
+trait TicketDb[F[_]]:
+  /** Create a new [[Ticket]] in the database.
+    *
+    * @param ticket
+    *   The [[Ticket]] to store.
+    * @return
+    *   The [[Ticket]] that was created, or an error.
+    */
+  def createTicket(ticket: Ticket): EitherT[F, DbError, Ticket]
+
+  /** Read the specified [[Ticket]] from the database.
+    *
+    * @param ref
+    *   The reference to the [[Ticket]] to retrieve.
+    * @return
+    *   The value of the [[Ticket]], or `None` if no such [[Ticket]] exists.
+    */
+  def readTicket(ref: Ticket.Reference): F[Option[Ticket]]
+
+  /** Given a reference to a [[Ticket]] and some new value for that [[Ticket]],
+    * update the [[Ticket]] in the database.
+    *
+    * @param ref
+    *   The refrence to the [[Ticket]] to update.
+    * @param newValue
+    *   The new values with which to overwrite the [[Ticket]].
+    * @return
+    *   The modified [[Ticket]] if the operation succeeded, or `None` if the
+    *   given reference does not exist.
+    */
+  def updateTicket(
+    ref: Ticket.Reference,
+    newValue: Ticket
+  ): F[Option[Ticket]]
+
+  /** Delete the specified [[Ticket]].
+    *
+    * @param ref
+    *   The reference to the [[Ticket]] to delete.
+    * @return
+    *   `true` if the operation deleted a [[Ticket]], `false` otherwise.
+    */
+  def deleteTicket(ref: Ticket.Reference): F[Boolean]
diff --git a/modules/db/src/main/scala/gs/smolban/db/doobie/DoobieTicketDb.scala b/modules/db/src/main/scala/gs/smolban/db/doobie/DoobieTicketDb.scala
new file mode 100644
index 0000000..0f2a9c5
--- /dev/null
+++ b/modules/db/src/main/scala/gs/smolban/db/doobie/DoobieTicketDb.scala
@@ -0,0 +1,27 @@
+package gs.smolban.db.doobie
+
+import cats.data.EitherT
+import cats.effect.Async
+import gs.smolban.db.DbError
+import gs.smolban.db.TicketDb
+import gs.smolban.model.Ticket
+
+final class DoobieTicketDb[F[_]: Async] extends TicketDb[F]:
+  /** @inheritdoc
+    */
+  override def createTicket(ticket: Ticket): EitherT[F, DbError, Ticket] = ???
+
+  /** @inheritdoc
+    */
+  override def readTicket(ref: Ticket.Reference): F[Option[Ticket]] = ???
+
+  /** @inheritdoc
+    */
+  override def updateTicket(
+    ref: Ticket.Reference,
+    newValue: Ticket
+  ): F[Option[Ticket]] = ???
+
+  /** @inheritdoc
+    */
+  override def deleteTicket(ref: Ticket.Reference): F[Boolean] = ???
diff --git a/modules/model/src/main/scala/gs/smolban/model/SmolbanError.scala b/modules/model/src/main/scala/gs/smolban/model/SmolbanError.scala
new file mode 100644
index 0000000..80c8089
--- /dev/null
+++ b/modules/model/src/main/scala/gs/smolban/model/SmolbanError.scala
@@ -0,0 +1,5 @@
+package gs.smolban.model
+
+/** The parent trait for all errors in Smolban.
+  */
+trait SmolbanError
diff --git a/modules/model/src/main/scala/gs/smolban/model/Ticket.scala b/modules/model/src/main/scala/gs/smolban/model/Ticket.scala
index 504019e..87b95e1 100644
--- a/modules/model/src/main/scala/gs/smolban/model/Ticket.scala
+++ b/modules/model/src/main/scala/gs/smolban/model/Ticket.scala
@@ -38,10 +38,23 @@ case class Ticket(
   status: Ticket.Status,
   statusHistory: List[(Ticket.Status, Instant)],
   assignee: Option[User.Id]
-)
+):
+  lazy val reference: Ticket.Reference = Ticket.Reference(id, group)
 
 object Ticket:
 
+  /** Composite reference that uniquely addresses any [[Ticket]].
+    *
+    * @param id
+    *   The ticket's unique identifier within the [[Group]].
+    * @param group
+    *   The unique identifier of the [[Group]].
+    */
+  case class Reference(
+    id: Ticket.Id,
+    group: Group.Id
+  )
+
   /** Unique identifier - relative to some [[Group]] - for a [[Ticket]]. This is
     * an opaque type for a Long. In general, [[Ticket]] identifiers are
     * sequences within a group.
diff --git a/project/build.properties b/project/build.properties
index 081fdbb..ee4c672 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.10.0
+sbt.version=1.10.1