diff --git a/cmd/controller/app/start.go b/cmd/controller/app/start.go
index 357f6d1..fe30599 100644
--- a/cmd/controller/app/start.go
+++ b/cmd/controller/app/start.go
@@ -14,7 +14,7 @@ import (
 	"github.com/oursky/pageship/internal/db"
 	_ "github.com/oursky/pageship/internal/db/postgres"
 	_ "github.com/oursky/pageship/internal/db/sqlite"
-	"github.com/oursky/pageship/internal/domain"
+	domaindb "github.com/oursky/pageship/internal/domain/db"
 	"github.com/oursky/pageship/internal/handler/controller"
 	"github.com/oursky/pageship/internal/handler/site"
 	"github.com/oursky/pageship/internal/handler/site/middleware"
@@ -129,7 +129,10 @@ func (s *setup) checkDomain(name string) error {
 }
 
 func (s *setup) sites(conf StartSitesConfig) error {
-	domainResolver := &domain.ResolverNull{} // FIXME: custom domain
+	domainResolver := &domaindb.Resolver{
+		HostIDScheme: conf.HostIDScheme,
+		DB:           s.database,
+	}
 	siteResolver := &sitedb.Resolver{
 		HostIDScheme: conf.HostIDScheme,
 		DB:           s.database,
diff --git a/internal/db/db.go b/internal/db/db.go
index fa8bb66..452c772 100644
--- a/internal/db/db.go
+++ b/internal/db/db.go
@@ -78,6 +78,7 @@ type DeploymentsDB interface {
 type DomainsDB interface {
 	CreateDomain(ctx context.Context, domain *models.Domain) error
 	GetDomainByName(ctx context.Context, domain string) (*models.Domain, error)
+	GetDomainBySite(ctx context.Context, appID string, siteName string) (*models.Domain, error)
 	DeleteDomain(ctx context.Context, id string, now time.Time) error
 	ListDomains(ctx context.Context, appID string) ([]*models.Domain, error)
 }
diff --git a/internal/db/postgres/domains.go b/internal/db/postgres/domains.go
index 6354ae2..53eadd5 100644
--- a/internal/db/postgres/domains.go
+++ b/internal/db/postgres/domains.go
@@ -48,6 +48,23 @@ func (q query[T]) GetDomainByName(ctx context.Context, domainName string) (*mode
 	return &domain, nil
 }
 
+func (q query[T]) GetDomainBySite(ctx context.Context, appID string, siteName string) (*models.Domain, error) {
+	var domain models.Domain
+
+	err := sqlx.GetContext(ctx, q.ext, &domain, `
+		SELECT d.id, d.created_at, d.updated_at, d.deleted_at, d.domain, d.app_id, d.site_name FROM domain_association d
+			JOIN app a ON (a.id = d.app_id AND a.deleted_at IS NULL)
+			WHERE d.app_id = $1 AND d.site_name = $2 AND d.deleted_at IS NULL
+	`, appID, siteName)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, models.ErrDomainNotFound
+	} else if err != nil {
+		return nil, err
+	}
+
+	return &domain, nil
+}
+
 func (q query[T]) DeleteDomain(ctx context.Context, id string, now time.Time) error {
 	_, err := q.ext.ExecContext(ctx, `
 		UPDATE domain_association SET deleted_at = $1 WHERE id = $2
diff --git a/internal/db/sqlite/domains.go b/internal/db/sqlite/domains.go
index 54e63a0..eb3800b 100644
--- a/internal/db/sqlite/domains.go
+++ b/internal/db/sqlite/domains.go
@@ -48,6 +48,23 @@ func (q query[T]) GetDomainByName(ctx context.Context, domainName string) (*mode
 	return &domain, nil
 }
 
+func (q query[T]) GetDomainBySite(ctx context.Context, appID string, siteName string) (*models.Domain, error) {
+	var domain models.Domain
+
+	err := sqlx.GetContext(ctx, q.ext, &domain, `
+		SELECT d.id, d.created_at, d.updated_at, d.deleted_at, d.domain, d.app_id, d.site_name FROM domain_association d
+			JOIN app a ON (a.id = d.app_id AND a.deleted_at IS NULL)
+			WHERE d.app_id = ? AND d.site_name = ? AND d.deleted_at IS NULL
+	`, appID, siteName)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, models.ErrDomainNotFound
+	} else if err != nil {
+		return nil, err
+	}
+
+	return &domain, nil
+}
+
 func (q query[T]) DeleteDomain(ctx context.Context, id string, now time.Time) error {
 	_, err := q.ext.ExecContext(ctx, `
 		UPDATE domain_association SET deleted_at = ? WHERE id = ?
diff --git a/internal/domain/db/resolver.go b/internal/domain/db/resolver.go
new file mode 100644
index 0000000..d03247c
--- /dev/null
+++ b/internal/domain/db/resolver.go
@@ -0,0 +1,38 @@
+package db
+
+import (
+	"context"
+	"errors"
+
+	"github.com/oursky/pageship/internal/config"
+	"github.com/oursky/pageship/internal/db"
+	"github.com/oursky/pageship/internal/domain"
+	"github.com/oursky/pageship/internal/models"
+)
+
+type Resolver struct {
+	DB           db.DB
+	HostIDScheme config.HostIDScheme
+}
+
+func (r *Resolver) Kind() string { return "database" }
+
+func (r *Resolver) Resolve(ctx context.Context, hostname string) (string, error) {
+	dom, err := r.DB.GetDomainByName(ctx, hostname)
+	if errors.Is(err, models.ErrDomainNotFound) {
+		return "", domain.ErrDomainNotFound
+	}
+
+	app, err := r.DB.GetApp(ctx, dom.AppID)
+	if errors.Is(err, models.ErrAppNotFound) {
+		return "", domain.ErrDomainNotFound
+	}
+
+	sub := dom.SiteName
+	if dom.SiteName == app.Config.DefaultSite {
+		sub = ""
+	}
+	id := r.HostIDScheme.Make(dom.AppID, sub)
+
+	return id, nil
+}
diff --git a/internal/site/db/resolver.go b/internal/site/db/resolver.go
index d836348..948ee0c 100644
--- a/internal/site/db/resolver.go
+++ b/internal/site/db/resolver.go
@@ -99,11 +99,23 @@ func (r *Resolver) Resolve(ctx context.Context, matchedID string) (*site.Descrip
 		config.Access = app.Config.Deployments.Access
 	}
 
+	domain, err := r.DB.GetDomainBySite(ctx, app.ID, siteName)
+	if errors.Is(err, models.ErrDomainNotFound) {
+		domain = nil
+	} else if err != nil {
+		return nil, err
+	}
+
+	domainName := ""
+	if domain != nil {
+		domainName = domain.Domain
+	}
+
 	id := strings.Join([]string{deployment.AppID, siteName, deployment.ID}, "/")
 	desc := &site.Descriptor{
 		ID:     id,
 		Config: &config,
-		Domain: "", // FIXME: custom domain
+		Domain: domainName,
 		FS:     newStorageFS(r.Storage, deployment),
 	}