diff --git a/modules/context/api.go b/modules/context/api.go
index 5d91ac49a..a843e79e4 100644
--- a/modules/context/api.go
+++ b/modules/context/api.go
@@ -251,3 +251,61 @@ func (ctx *APIContext) NotFound(objs ...interface{}) {
 		"errors":            errors,
 	})
 }
+
+// RepoRefForAPI handles repository reference names when the ref name is not explicitly given
+func RepoRefForAPI() macaron.Handler {
+	return func(ctx *APIContext) {
+		// Empty repository does not have reference information.
+		if ctx.Repo.Repository.IsEmpty {
+			return
+		}
+
+		var err error
+
+		if ctx.Repo.GitRepo == nil {
+			repoPath := models.RepoPath(ctx.Repo.Owner.Name, ctx.Repo.Repository.Name)
+			ctx.Repo.GitRepo, err = git.OpenRepository(repoPath)
+			if err != nil {
+				ctx.InternalServerError(err)
+				return
+			}
+			// We opened it, we should close it
+			defer func() {
+				// If it's been set to nil then assume someone else has closed it.
+				if ctx.Repo.GitRepo != nil {
+					ctx.Repo.GitRepo.Close()
+				}
+			}()
+		}
+
+		refName := getRefName(ctx.Context, RepoRefAny)
+
+		if ctx.Repo.GitRepo.IsBranchExist(refName) {
+			ctx.Repo.Commit, err = ctx.Repo.GitRepo.GetBranchCommit(refName)
+			if err != nil {
+				ctx.InternalServerError(err)
+				return
+			}
+			ctx.Repo.CommitID = ctx.Repo.Commit.ID.String()
+		} else if ctx.Repo.GitRepo.IsTagExist(refName) {
+			ctx.Repo.Commit, err = ctx.Repo.GitRepo.GetTagCommit(refName)
+			if err != nil {
+				ctx.InternalServerError(err)
+				return
+			}
+			ctx.Repo.CommitID = ctx.Repo.Commit.ID.String()
+		} else if len(refName) == 40 {
+			ctx.Repo.CommitID = refName
+			ctx.Repo.Commit, err = ctx.Repo.GitRepo.GetCommit(refName)
+			if err != nil {
+				ctx.NotFound("GetCommit", err)
+				return
+			}
+		} else {
+			ctx.NotFound(fmt.Errorf("not exist: '%s'", ctx.Params("*")))
+			return
+		}
+
+		ctx.Next()
+	}
+}
diff --git a/modules/context/repo.go b/modules/context/repo.go
index 5ebed0eb7..a749ab04e 100644
--- a/modules/context/repo.go
+++ b/modules/context/repo.go
@@ -690,7 +690,6 @@ func RepoRefByType(refType RepoRefType) macaron.Handler {
 			err     error
 		)
 
-		// For API calls.
 		if ctx.Repo.GitRepo == nil {
 			repoPath := models.RepoPath(ctx.Repo.Owner.Name, ctx.Repo.Repository.Name)
 			ctx.Repo.GitRepo, err = git.OpenRepository(repoPath)
@@ -759,7 +758,7 @@ func RepoRefByType(refType RepoRefType) macaron.Handler {
 
 				ctx.Repo.Commit, err = ctx.Repo.GitRepo.GetCommit(refName)
 				if err != nil {
-					ctx.NotFound("GetCommit", nil)
+					ctx.NotFound("GetCommit", err)
 					return
 				}
 			} else {
diff --git a/routers/api/v1/api.go b/routers/api/v1/api.go
index 5581f1ff2..9253b5b2c 100644
--- a/routers/api/v1/api.go
+++ b/routers/api/v1/api.go
@@ -184,14 +184,14 @@ func reqToken() macaron.Handler {
 			ctx.RequireCSRF()
 			return
 		}
-		ctx.Context.Error(http.StatusUnauthorized)
+		ctx.Error(http.StatusUnauthorized, "reqToken", "token is required")
 	}
 }
 
 func reqBasicAuth() macaron.Handler {
 	return func(ctx *context.APIContext) {
 		if !ctx.Context.IsBasicAuth {
-			ctx.Context.Error(http.StatusUnauthorized)
+			ctx.Error(http.StatusUnauthorized, "reqBasicAuth", "basic auth required")
 			return
 		}
 		ctx.CheckForOTP()
@@ -200,9 +200,9 @@ func reqBasicAuth() macaron.Handler {
 
 // reqSiteAdmin user should be the site admin
 func reqSiteAdmin() macaron.Handler {
-	return func(ctx *context.Context) {
+	return func(ctx *context.APIContext) {
 		if !ctx.IsUserSiteAdmin() {
-			ctx.Error(http.StatusForbidden)
+			ctx.Error(http.StatusForbidden, "reqSiteAdmin", "user should be the site admin")
 			return
 		}
 	}
@@ -210,9 +210,9 @@ func reqSiteAdmin() macaron.Handler {
 
 // reqOwner user should be the owner of the repo or site admin.
 func reqOwner() macaron.Handler {
-	return func(ctx *context.Context) {
+	return func(ctx *context.APIContext) {
 		if !ctx.IsUserRepoOwner() && !ctx.IsUserSiteAdmin() {
-			ctx.Error(http.StatusForbidden)
+			ctx.Error(http.StatusForbidden, "reqOwner", "user should be the owner of the repo")
 			return
 		}
 	}
@@ -220,9 +220,9 @@ func reqOwner() macaron.Handler {
 
 // reqAdmin user should be an owner or a collaborator with admin write of a repository, or site admin
 func reqAdmin() macaron.Handler {
-	return func(ctx *context.Context) {
+	return func(ctx *context.APIContext) {
 		if !ctx.IsUserRepoAdmin() && !ctx.IsUserSiteAdmin() {
-			ctx.Error(http.StatusForbidden)
+			ctx.Error(http.StatusForbidden, "reqAdmin", "user should be an owner or a collaborator with admin write of a repository")
 			return
 		}
 	}
@@ -230,9 +230,9 @@ func reqAdmin() macaron.Handler {
 
 // reqRepoWriter user should have a permission to write to a repo, or be a site admin
 func reqRepoWriter(unitTypes ...models.UnitType) macaron.Handler {
-	return func(ctx *context.Context) {
+	return func(ctx *context.APIContext) {
 		if !ctx.IsUserRepoWriter(unitTypes) && !ctx.IsUserRepoAdmin() && !ctx.IsUserSiteAdmin() {
-			ctx.Error(http.StatusForbidden)
+			ctx.Error(http.StatusForbidden, "reqRepoWriter", "user should have a permission to write to a repo")
 			return
 		}
 	}
@@ -240,9 +240,9 @@ func reqRepoWriter(unitTypes ...models.UnitType) macaron.Handler {
 
 // reqRepoReader user should have specific read permission or be a repo admin or a site admin
 func reqRepoReader(unitType models.UnitType) macaron.Handler {
-	return func(ctx *context.Context) {
+	return func(ctx *context.APIContext) {
 		if !ctx.IsUserRepoReaderSpecific(unitType) && !ctx.IsUserRepoAdmin() && !ctx.IsUserSiteAdmin() {
-			ctx.Error(http.StatusForbidden)
+			ctx.Error(http.StatusForbidden, "reqRepoReader", "user should have specific read permission or be a repo admin or a site admin")
 			return
 		}
 	}
@@ -250,9 +250,9 @@ func reqRepoReader(unitType models.UnitType) macaron.Handler {
 
 // reqAnyRepoReader user should have any permission to read repository or permissions of site admin
 func reqAnyRepoReader() macaron.Handler {
-	return func(ctx *context.Context) {
+	return func(ctx *context.APIContext) {
 		if !ctx.IsUserRepoReaderAny() && !ctx.IsUserSiteAdmin() {
-			ctx.Error(http.StatusForbidden)
+			ctx.Error(http.StatusForbidden, "reqAnyRepoReader", "user should have any permission to read repository or permissions of site admin")
 			return
 		}
 	}
@@ -495,7 +495,6 @@ func mustNotBeArchived(ctx *context.APIContext) {
 }
 
 // RegisterRoutes registers all v1 APIs routes to web application.
-// FIXME: custom form error response
 func RegisterRoutes(m *macaron.Macaron) {
 	bind := binding.Bind
 
@@ -628,7 +627,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 			m.Group("/:username/:reponame", func() {
 				m.Combo("").Get(reqAnyRepoReader(), repo.Get).
 					Delete(reqToken(), reqOwner(), repo.Delete).
-					Patch(reqToken(), reqAdmin(), bind(api.EditRepoOption{}), context.RepoRef(), repo.Edit)
+					Patch(reqToken(), reqAdmin(), bind(api.EditRepoOption{}), context.RepoRefForAPI(), repo.Edit)
 				m.Post("/transfer", reqOwner(), bind(api.TransferRepoOption{}), repo.Transfer)
 				m.Combo("/notifications").
 					Get(reqToken(), notify.ListRepoNotifications).
@@ -640,7 +639,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 						m.Combo("").Get(repo.GetHook).
 							Patch(bind(api.EditHookOption{}), repo.EditHook).
 							Delete(repo.DeleteHook)
-						m.Post("/tests", context.RepoRef(), repo.TestHook)
+						m.Post("/tests", context.RepoRefForAPI(), repo.TestHook)
 					})
 					m.Group("/git", func() {
 						m.Combo("").Get(repo.ListGitHooks)
@@ -657,14 +656,14 @@ func RegisterRoutes(m *macaron.Macaron) {
 						Put(reqAdmin(), bind(api.AddCollaboratorOption{}), repo.AddCollaborator).
 						Delete(reqAdmin(), repo.DeleteCollaborator)
 				}, reqToken())
-				m.Get("/raw/*", context.RepoRefByType(context.RepoRefAny), reqRepoReader(models.UnitTypeCode), repo.GetRawFile)
+				m.Get("/raw/*", context.RepoRefForAPI(), reqRepoReader(models.UnitTypeCode), repo.GetRawFile)
 				m.Get("/archive/*", reqRepoReader(models.UnitTypeCode), repo.GetArchive)
 				m.Combo("/forks").Get(repo.ListForks).
 					Post(reqToken(), reqRepoReader(models.UnitTypeCode), bind(api.CreateForkOption{}), repo.CreateFork)
 				m.Group("/branches", func() {
 					m.Get("", repo.ListBranches)
-					m.Get("/*", context.RepoRefByType(context.RepoRefBranch), repo.GetBranch)
-					m.Delete("/*", reqRepoWriter(models.UnitTypeCode), context.RepoRefByType(context.RepoRefBranch), repo.DeleteBranch)
+					m.Get("/*", repo.GetBranch)
+					m.Delete("/*", context.ReferencesGitRepo(false), reqRepoWriter(models.UnitTypeCode), repo.DeleteBranch)
 				}, reqRepoReader(models.UnitTypeCode))
 				m.Group("/branch_protections", func() {
 					m.Get("", repo.ListBranchProtections)
@@ -785,7 +784,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 					})
 				}, reqRepoReader(models.UnitTypeReleases))
 				m.Post("/mirror-sync", reqToken(), reqRepoWriter(models.UnitTypeCode), repo.MirrorSync)
-				m.Get("/editorconfig/:filename", context.RepoRef(), reqRepoReader(models.UnitTypeCode), repo.GetEditorconfig)
+				m.Get("/editorconfig/:filename", context.RepoRefForAPI(), reqRepoReader(models.UnitTypeCode), repo.GetEditorconfig)
 				m.Group("/pulls", func() {
 					m.Combo("").Get(bind(api.ListPullRequestsOptions{}), repo.ListPullRequests).
 						Post(reqToken(), mustNotBeArchived, bind(api.CreatePullRequestOption{}), repo.CreatePullRequest)
@@ -827,9 +826,9 @@ func RegisterRoutes(m *macaron.Macaron) {
 					})
 					m.Get("/refs", repo.GetGitAllRefs)
 					m.Get("/refs/*", repo.GetGitRefs)
-					m.Get("/trees/:sha", context.RepoRef(), repo.GetTree)
-					m.Get("/blobs/:sha", context.RepoRef(), repo.GetBlob)
-					m.Get("/tags/:sha", context.RepoRef(), repo.GetTag)
+					m.Get("/trees/:sha", context.RepoRefForAPI(), repo.GetTree)
+					m.Get("/blobs/:sha", context.RepoRefForAPI(), repo.GetBlob)
+					m.Get("/tags/:sha", context.RepoRefForAPI(), repo.GetTag)
 				}, reqRepoReader(models.UnitTypeCode))
 				m.Group("/contents", func() {
 					m.Get("", repo.GetContentsList)
diff --git a/routers/api/v1/repo/branch.go b/routers/api/v1/repo/branch.go
index 57c74d7da..74b8bbcd8 100644
--- a/routers/api/v1/repo/branch.go
+++ b/routers/api/v1/repo/branch.go
@@ -45,15 +45,12 @@ func GetBranch(ctx *context.APIContext) {
 	// responses:
 	//   "200":
 	//     "$ref": "#/responses/Branch"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
 
-	if ctx.Repo.TreePath != "" {
-		// if TreePath != "", then URL contained extra slashes
-		// (i.e. "master/subbranch" instead of "master"), so branch does
-		// not exist
-		ctx.NotFound()
-		return
-	}
-	branch, err := repo_module.GetBranch(ctx.Repo.Repository, ctx.Repo.BranchName)
+	branchName := ctx.Params("*")
+
+	branch, err := repo_module.GetBranch(ctx.Repo.Repository, branchName)
 	if err != nil {
 		if git.IsErrBranchNotExist(err) {
 			ctx.NotFound(err)
@@ -69,7 +66,7 @@ func GetBranch(ctx *context.APIContext) {
 		return
 	}
 
-	branchProtection, err := ctx.Repo.Repository.GetBranchProtection(ctx.Repo.BranchName)
+	branchProtection, err := ctx.Repo.Repository.GetBranchProtection(branchName)
 	if err != nil {
 		ctx.Error(http.StatusInternalServerError, "GetBranchProtection", err)
 		return
@@ -112,21 +109,17 @@ func DeleteBranch(ctx *context.APIContext) {
 	//     "$ref": "#/responses/empty"
 	//   "403":
 	//     "$ref": "#/responses/error"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
 
-	if ctx.Repo.TreePath != "" {
-		// if TreePath != "", then URL contained extra slashes
-		// (i.e. "master/subbranch" instead of "master"), so branch does
-		// not exist
-		ctx.NotFound()
-		return
-	}
+	branchName := ctx.Params("*")
 
-	if ctx.Repo.Repository.DefaultBranch == ctx.Repo.BranchName {
+	if ctx.Repo.Repository.DefaultBranch == branchName {
 		ctx.Error(http.StatusForbidden, "DefaultBranch", fmt.Errorf("can not delete default branch"))
 		return
 	}
 
-	isProtected, err := ctx.Repo.Repository.IsProtectedBranch(ctx.Repo.BranchName, ctx.User)
+	isProtected, err := ctx.Repo.Repository.IsProtectedBranch(branchName, ctx.User)
 	if err != nil {
 		ctx.InternalServerError(err)
 		return
@@ -136,7 +129,7 @@ func DeleteBranch(ctx *context.APIContext) {
 		return
 	}
 
-	branch, err := repo_module.GetBranch(ctx.Repo.Repository, ctx.Repo.BranchName)
+	branch, err := repo_module.GetBranch(ctx.Repo.Repository, branchName)
 	if err != nil {
 		if git.IsErrBranchNotExist(err) {
 			ctx.NotFound(err)
@@ -152,7 +145,7 @@ func DeleteBranch(ctx *context.APIContext) {
 		return
 	}
 
-	if err := ctx.Repo.GitRepo.DeleteBranch(ctx.Repo.BranchName, git.DeleteBranchOptions{
+	if err := ctx.Repo.GitRepo.DeleteBranch(branchName, git.DeleteBranchOptions{
 		Force: true,
 	}); err != nil {
 		ctx.Error(http.StatusInternalServerError, "DeleteBranch", err)
@@ -164,7 +157,7 @@ func DeleteBranch(ctx *context.APIContext) {
 		ctx.Repo.Repository,
 		ctx.Repo.BranchName,
 		repofiles.PushUpdateOptions{
-			RefFullName:  git.BranchPrefix + ctx.Repo.BranchName,
+			RefFullName:  git.BranchPrefix + branchName,
 			OldCommitID:  c.ID.String(),
 			NewCommitID:  git.EmptySHA,
 			PusherID:     ctx.User.ID,
@@ -175,7 +168,7 @@ func DeleteBranch(ctx *context.APIContext) {
 		log.Error("Update: %v", err)
 	}
 
-	if err := ctx.Repo.Repository.AddDeletedBranch(ctx.Repo.BranchName, c.ID.String(), ctx.User.ID); err != nil {
+	if err := ctx.Repo.Repository.AddDeletedBranch(branchName, c.ID.String(), ctx.User.ID); err != nil {
 		log.Warn("AddDeletedBranch: %v", err)
 	}
 
diff --git a/templates/swagger/v1_json.tmpl b/templates/swagger/v1_json.tmpl
index 12c732a9a..0c9649897 100644
--- a/templates/swagger/v1_json.tmpl
+++ b/templates/swagger/v1_json.tmpl
@@ -2318,6 +2318,9 @@
         "responses": {
           "200": {
             "$ref": "#/responses/Branch"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
           }
         }
       },
@@ -2359,6 +2362,9 @@
           },
           "403": {
             "$ref": "#/responses/error"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
           }
         }
       }