diff --git a/changelog/unreleased/add-rebuild-jsoncs3-index-command.md b/changelog/unreleased/add-rebuild-jsoncs3-index-command.md
new file mode 100644
index 000000000..6998c9a1d
--- /dev/null
+++ b/changelog/unreleased/add-rebuild-jsoncs3-index-command.md
@@ -0,0 +1,5 @@
+Enhancement: Add command for rebuilding the jsoncs3 share manager indexes
+
+We added a command for rebuilding the jsoncs3 share manager indexes.
+
+https://github.com/owncloud/ocis/pull/6971
diff --git a/ocis/pkg/command/migrate.go b/ocis/pkg/command/migrate.go
index 379f52559..f978381a2 100644
--- a/ocis/pkg/command/migrate.go
+++ b/ocis/pkg/command/migrate.go
@@ -2,25 +2,38 @@ package command
 
 import (
 	"context"
+	"encoding/json"
+	"fmt"
 	"os"
+	"path/filepath"
 	"sort"
+	"strings"
 	"sync"
 
 	collaboration "github.com/cs3org/go-cs3apis/cs3/sharing/collaboration/v1beta1"
+	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
 	"github.com/cs3org/reva/v2/pkg/publicshare"
 	publicregistry "github.com/cs3org/reva/v2/pkg/publicshare/manager/registry"
+	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	"github.com/cs3org/reva/v2/pkg/share"
+	"github.com/cs3org/reva/v2/pkg/share/manager/jsoncs3"
+	"github.com/cs3org/reva/v2/pkg/share/manager/jsoncs3/providercache"
+	"github.com/cs3org/reva/v2/pkg/share/manager/jsoncs3/shareid"
 	"github.com/cs3org/reva/v2/pkg/share/manager/registry"
 	"github.com/cs3org/reva/v2/pkg/storage/utils/decomposedfs/lookup"
 	"github.com/cs3org/reva/v2/pkg/storage/utils/decomposedfs/migrator"
 	"github.com/cs3org/reva/v2/pkg/storage/utils/decomposedfs/options"
+	"github.com/cs3org/reva/v2/pkg/storage/utils/metadata"
+	"github.com/mitchellh/mapstructure"
 	tw "github.com/olekukonko/tablewriter"
+	"github.com/pkg/errors"
 	"github.com/rs/zerolog"
 
 	"github.com/owncloud/ocis/v2/ocis-pkg/config"
 	"github.com/owncloud/ocis/v2/ocis-pkg/config/configlog"
 	"github.com/owncloud/ocis/v2/ocis-pkg/config/parser"
 	oclog "github.com/owncloud/ocis/v2/ocis-pkg/log"
+	mregistry "github.com/owncloud/ocis/v2/ocis-pkg/registry"
 	"github.com/owncloud/ocis/v2/ocis/pkg/register"
 	sharing "github.com/owncloud/ocis/v2/services/sharing/pkg/config"
 	sharingparser "github.com/owncloud/ocis/v2/services/sharing/pkg/config/parser"
@@ -37,6 +50,7 @@ func Migrate(cfg *config.Config) *cli.Command {
 			MigrateDecomposedfs(cfg),
 			MigrateShares(cfg),
 			MigratePublicShares(cfg),
+			RebuildJSONCS3Indexes(cfg),
 		},
 	}
 }
@@ -45,6 +59,142 @@ func init() {
 	register.AddCommand(Migrate)
 }
 
+// RebuildJSONCS3Indexes rebuilds the share indexes from the shares json
+func RebuildJSONCS3Indexes(cfg *config.Config) *cli.Command {
+	return &cli.Command{
+		Name:  "rebuild-jsoncs3-indexes",
+		Usage: "rebuild the share indexes from the shares json",
+		Subcommands: []*cli.Command{
+			ListDecomposedfsMigrations(cfg),
+		},
+		Flags: []cli.Flag{},
+		Before: func(c *cli.Context) error {
+			// Parse base config
+			if err := parser.ParseConfig(cfg, true); err != nil {
+				return configlog.ReturnError(err)
+			}
+
+			// Parse sharing config
+			cfg.Sharing.Commons = cfg.Commons
+			return configlog.ReturnError(sharingparser.ParseConfig(cfg.Sharing))
+		},
+		Action: func(c *cli.Context) error {
+			log := logger()
+			ctx := log.WithContext(context.Background())
+			rcfg := revaShareConfig(cfg.Sharing)
+
+			// Initialize registry to make service lookup work
+			_ = mregistry.GetRegistry()
+
+			// Get a jsoncs3 manager to operate its caches
+			type config struct {
+				GatewayAddr       string `mapstructure:"gateway_addr"`
+				MaxConcurrency    int    `mapstructure:"max_concurrency"`
+				ProviderAddr      string `mapstructure:"provider_addr"`
+				ServiceUserID     string `mapstructure:"service_user_id"`
+				ServiceUserIdp    string `mapstructure:"service_user_idp"`
+				MachineAuthAPIKey string `mapstructure:"machine_auth_apikey"`
+			}
+			conf := &config{}
+			if err := mapstructure.Decode(rcfg["jsoncs3"], conf); err != nil {
+				err = errors.Wrap(err, "error creating a new manager")
+				return err
+			}
+			s, err := metadata.NewCS3Storage(conf.GatewayAddr, conf.ProviderAddr, conf.ServiceUserID, conf.ServiceUserIdp, conf.MachineAuthAPIKey)
+			if err != nil {
+				return err
+			}
+			err = s.Init(ctx, "jsoncs3-share-manager-metadata")
+			if err != nil {
+				return err
+			}
+			gc, err := pool.GetGatewayServiceClient(conf.GatewayAddr)
+			if err != nil {
+				return err
+			}
+			mgr, err := jsoncs3.New(s, gc, 0, nil, 1)
+			if err != nil {
+				return err
+			}
+
+			// Rebuild indexes
+			errorsOccured := false
+			storages, err := s.ReadDir(ctx, "storages")
+			if err != nil {
+				return err
+			}
+			for iStorage, storage := range storages {
+				fmt.Printf("Scanning storage %s (%d/%d)\n", storage, iStorage+1, len(storages))
+				spaces, err := s.ReadDir(ctx, filepath.Join("storages", storage))
+				if err != nil {
+					fmt.Printf("failed! (%s)\n", err.Error())
+					errorsOccured = true
+					continue
+				}
+
+				for iSpace, space := range spaces {
+					fmt.Printf("  Rebuilding space '%s' %d/%d...", strings.TrimSuffix(space, ".json"), iSpace+1, len(spaces))
+
+					spaceBlob, err := s.SimpleDownload(ctx, filepath.Join("storages", storage, space))
+					if err != nil {
+						fmt.Printf(" failed! (%s)\n", err.Error())
+						errorsOccured = true
+						continue
+					}
+					shares := &providercache.Shares{}
+					err = json.Unmarshal(spaceBlob, shares)
+					if err != nil {
+						fmt.Printf(" failed! (%s)\n", err.Error())
+						errorsOccured = true
+						continue
+					}
+					for _, share := range shares.Shares {
+						err = mgr.Cache.Add(ctx, share.ResourceId.StorageId, share.ResourceId.SpaceId, share.Id.OpaqueId, share)
+						if err != nil {
+							fmt.Printf(" adding share '%s' to the cache failed! (%s)\n", share.Id.OpaqueId, err.Error())
+							errorsOccured = true
+						}
+						err = mgr.CreatedCache.Add(ctx, share.Creator.OpaqueId, share.Id.OpaqueId)
+						if err != nil {
+							fmt.Printf(" adding share '%s' to the created cache failed! (%s)\n", share.Id.OpaqueId, err.Error())
+							errorsOccured = true
+						}
+
+						spaceId := share.ResourceId.StorageId + shareid.IDDelimiter + share.ResourceId.SpaceId
+						switch share.Grantee.Type {
+						case provider.GranteeType_GRANTEE_TYPE_USER:
+							userid := share.Grantee.GetUserId().GetOpaqueId()
+							rs := &collaboration.ReceivedShare{
+								Share: share,
+								State: collaboration.ShareState_SHARE_STATE_PENDING,
+							}
+							err := mgr.UserReceivedStates.Add(ctx, userid, spaceId, rs)
+							if err != nil {
+								fmt.Printf(" adding share '%s' to the user cache failed! (%s)\n", share.Id.OpaqueId, err.Error())
+								errorsOccured = true
+							}
+						case provider.GranteeType_GRANTEE_TYPE_GROUP:
+							groupid := share.Grantee.GetGroupId().GetOpaqueId()
+							err := mgr.GroupReceivedCache.Add(ctx, groupid, spaceId)
+							if err != nil {
+								fmt.Printf(" adding share '%s' to the group cache failed! (%s)\n", share.Id.OpaqueId, err.Error())
+								errorsOccured = true
+							}
+						}
+					}
+					fmt.Printf("  done\n")
+				}
+				fmt.Printf("done\n")
+			}
+			if errorsOccured {
+				fmt.Printf("There were errors. Please review the logs.")
+			}
+
+			return nil
+		},
+	}
+}
+
 // MigrateDecomposedfs is the entrypoint for the decomposedfs migrate command
 func MigrateDecomposedfs(cfg *config.Config) *cli.Command {
 	return &cli.Command{