diff --git a/internal/api/abort.go b/internal/api/abort.go
index d1c9dd7bf..ba84c45ed 100644
--- a/internal/api/abort.go
+++ b/internal/api/abort.go
@@ -1,7 +1,7 @@
 package api
 
 import (
-	_ "embed"
+	_ "embed" // required for go:embed video placeholder
 	"net/http"
 	"strings"
 
@@ -18,6 +18,7 @@ import (
 //go:embed embed/video.mp4
 var brokenVideo []byte
 
+// Abort writes a localized error response and stops further handler processing.
 func Abort(c *gin.Context, code int, id i18n.Message, params ...interface{}) {
 	resp := i18n.NewResponse(code, id, params...)
 
@@ -30,6 +31,7 @@ func Abort(c *gin.Context, code int, id i18n.Message, params ...interface{}) {
 	c.AbortWithStatusJSON(code, resp)
 }
 
+// Error aborts the request while attaching error details to the response payload.
 func Error(c *gin.Context, code int, err error, id i18n.Message, params ...interface{}) {
 	resp := i18n.NewResponse(code, id, params...)
 
@@ -95,22 +97,27 @@ func AbortAlbumNotFound(c *gin.Context) {
 	Abort(c, http.StatusNotFound, i18n.ErrAlbumNotFound)
 }
 
+// AbortSaveFailed aborts with a generic 500 "save failed" error.
 func AbortSaveFailed(c *gin.Context) {
 	Abort(c, http.StatusInternalServerError, i18n.ErrSaveFailed)
 }
 
+// AbortDeleteFailed aborts with a generic 500 "delete failed" error.
 func AbortDeleteFailed(c *gin.Context) {
 	Abort(c, http.StatusInternalServerError, i18n.ErrDeleteFailed)
 }
 
+// AbortNotImplemented aborts with status 501 when a feature is unavailable.
 func AbortNotImplemented(c *gin.Context) {
 	Abort(c, http.StatusNotImplemented, i18n.ErrUnsupported)
 }
 
+// AbortUnexpectedError aborts with a generic 500 error.
 func AbortUnexpectedError(c *gin.Context) {
 	Abort(c, http.StatusInternalServerError, i18n.ErrUnexpected)
 }
 
+// AbortBadRequest attaches validation details and responds with status 400.
 func AbortBadRequest(c *gin.Context, errs ...error) {
 	// Log and attach validation errors to the context.
 	for _, err := range errs {
@@ -127,34 +134,41 @@ func AbortBadRequest(c *gin.Context, errs ...error) {
 	Abort(c, http.StatusBadRequest, i18n.ErrBadRequest)
 }
 
+// AbortFeatureDisabled aborts with a forbidden response when a feature is disabled.
 func AbortFeatureDisabled(c *gin.Context) {
 	Abort(c, http.StatusForbidden, i18n.ErrFeatureDisabled)
 }
 
+// AbortQuotaExceeded aborts with a forbidden response when quotas are exhausted.
 func AbortQuotaExceeded(c *gin.Context) {
 	Abort(c, http.StatusForbidden, i18n.ErrQuotaExceeded)
 }
 
+// AbortBusy responds with HTTP 429 to signal temporary overload.
 func AbortBusy(c *gin.Context) {
 	Abort(c, http.StatusTooManyRequests, i18n.ErrBusy)
 }
 
+// AbortInvalidName aborts with HTTP 400 when a name fails validation.
 func AbortInvalidName(c *gin.Context) {
 	Abort(c, http.StatusBadRequest, i18n.ErrInvalidName)
 }
 
+// AbortInvalidCredentials responds with HTTP 401 for failed authentication attempts.
 func AbortInvalidCredentials(c *gin.Context) {
 	if c != nil {
 		c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": authn.ErrInvalidCredentials.Error(), "code": i18n.ErrInvalidCredentials, "message": i18n.Msg(i18n.ErrInvalidCredentials)})
 	}
 }
 
+// AbortVideo writes a placeholder MP4 response for video errors.
 func AbortVideo(c *gin.Context) {
 	if c != nil {
 		AbortVideoWithStatus(c, http.StatusOK)
 	}
 }
 
+// AbortVideoWithStatus writes the placeholder MP4 response using the provided status code.
 func AbortVideoWithStatus(c *gin.Context, code int) {
 	if c != nil {
 		c.Data(code, header.ContentTypeMp4AvcMain, brokenVideo)
diff --git a/internal/api/api_event.go b/internal/api/api_event.go
index 2774dee3e..d28b072c8 100644
--- a/internal/api/api_event.go
+++ b/internal/api/api_event.go
@@ -11,6 +11,7 @@ import (
 // Event represents an api event type.
 type Event string
 
+// Canonical event payload status strings used by the API layer.
 const (
 	StatusCreated Event = "created"
 	StatusUpdated Event = "updated"
diff --git a/internal/api/cache.go b/internal/api/cache.go
index b5dab9fc6..dc3b0ec98 100644
--- a/internal/api/cache.go
+++ b/internal/api/cache.go
@@ -16,11 +16,13 @@ import (
 	"github.com/photoprism/photoprism/pkg/service/http/header"
 )
 
+// ThumbCache describes files persisted on disk for cached thumbnails and share images.
 type ThumbCache struct {
 	FileName  string
 	ShareName string
 }
 
+// ByteCache wraps in-memory cached byte slices for fast responses.
 type ByteCache struct {
 	Data []byte
 }
diff --git a/internal/api/doc_overrides.go b/internal/api/doc_overrides.go
index 2a87c60a3..da7391f39 100644
--- a/internal/api/doc_overrides.go
+++ b/internal/api/doc_overrides.go
@@ -2,11 +2,9 @@ package api
 
 import "time"
 
-// Schema Overrides for Swagger generation.
-
-// Override the generated schema for time.Duration to avoid unstable enums
-// from the standard library constants (Nanosecond, Minute, etc.). Using
-// a simple integer schema is accurate (nanoseconds) and deterministic.
+// SwaggerTimeDuration overrides the generated schema for time.Duration to avoid unstable enums
+// from the standard library constants (Nanosecond, Minute, etc.). Using a simple integer schema is
+// accurate (nanoseconds) and deterministic.
 //
 //	@name			time.Duration
 //	@description	Duration in nanoseconds (int64). Examples: 1000000000 (1s), 60000000000 (1m).
diff --git a/internal/api/download/paths.go b/internal/api/download/paths.go
index d874a25da..ff2aed0c2 100644
--- a/internal/api/download/paths.go
+++ b/internal/api/download/paths.go
@@ -7,6 +7,7 @@ import (
 	"github.com/photoprism/photoprism/pkg/fs"
 )
 
+// AllowedPaths lists absolute directories from which downloads may be registered.
 var AllowedPaths []string
 
 // Deny checks if the filename may not be registered for download.
diff --git a/internal/api/import.go b/internal/api/import.go
index c1e73c9dc..7c00b2720 100644
--- a/internal/api/import.go
+++ b/internal/api/import.go
@@ -24,6 +24,7 @@ import (
 	"github.com/photoprism/photoprism/pkg/txt"
 )
 
+// UploadPath is the root directory underneath which user uploads are staged.
 const (
 	UploadPath = "/upload"
 )