diff --git a/PLUGINS.md b/PLUGINS.md
new file mode 100644
index 000000000..42cc87bd8
--- /dev/null
+++ b/PLUGINS.md
@@ -0,0 +1,267 @@
+# containerd Plugins
+
+containerd supports extending its functionality using most of its defined
+interfaces. This includes using a customized runtime, snapshotter, content
+store, and even adding gRPC interfaces.
+
+## Smart Client Model
+
+containerd has a smart client architecture, meaning any functionality which is
+not required by the daemon is done by the client. This includes most high
+level interactions such as creating a container's specification, interacting
+with an image registry, or loading an image from tar. containerd's Go client
+gives a user access to many points of extensions from creating their own
+options on container creation to resolving image registry names.
+
+See [containerd's Go documentation](https://godoc.org/github.com/containerd/containerd)
+
+## External Plugins
+
+External plugins allow extending containerd's functionality using an officially
+released version of containerd without needing to recompile the daemon to add a
+plugin.
+
+containerd allows extensions through two method:
+ - via a binary available in containerd's PATH
+ - by configuring containerd to proxy to another gRPC service
+
+### V2 Runtimes
+
+The runtime v2 interface allows resolving runtimes to binaries on the system.
+These binaries are used to start the shim process for containerd and allows
+containerd to manage those containers using the runtime shim api returned by
+the binary.
+
+See [runtime v2 documentation](runtime/v2/README.md)
+
+### Proxy Plugins
+
+A proxy plugin is configured using containerd's config file and will be loaded
+alongside the internal plugins when containerd is started. These plugins are
+connected to containerd using a local socket serving one of containerd's gRPC
+API services. Each plugin is configured with a type and name just as internal
+plugins are.
+
+#### Configuration
+
+Update the containerd config file, which by default is at
+`/etc/containerd/config.toml`. Add a `[proxy_plugins]` section along with a
+section for your given plugin `[proxy_plugins.myplugin]`. The `address` must
+refer to a local socket file which the containerd process has access to. The
+currently supported types are `snapshot` and `content`.
+
+```
+[proxy_plugins]
+  [proxy_plugins.customsnapshot]
+    type = "snapshot"
+    address = "/var/run/mysnapshotter.sock"
+```
+
+#### Implementation
+
+Implementing a proxy plugin is as easy as implementing the gRPC API for a
+service. For implementing a proxy plugin in Go, look at the go doc for
+[content store service](https://godoc.org/github.com/containerd/containerd/api/services/content/v1#ContentServer)
+and [snapshotter service](https://godoc.org/github.com/containerd/containerd/api/services/snapshots/v1#SnapshotsServer).
+
+The following example creates a snapshot plugin binary which can be used
+with any implementation of
+[containerd's Snapshotter interface](https://godoc.org/github.com/containerd/containerd/snapshots#Snapshotter)
+```go
+package main
+
+import (
+	"fmt"
+	"net"
+	"os"
+
+	"google.golang.org/grpc"
+
+	snapshotsapi "github.com/containerd/containerd/api/services/snapshots/v1"
+	"github.com/containerd/containerd/contrib/snapshotservice"
+	"github.com/containerd/containerd/snapshots/native"
+)
+
+func main() {
+	// Provide a unix address to listen to, this will be the `address`
+	// in the `proxy_plugin` configuration.
+	// The root will be used to store the snapshots.
+	if len(os.Args) < 3 {
+		fmt.Printf("invalid args: usage: %s <unix addr> <root>\n", os.Args[0])
+		os.Exit(1)
+	}
+
+	// Create a gRPC server
+	rpc := grpc.NewServer()
+
+	// Configure your custom snapshotter, this example uses the native
+	// snapshotter and a root directory. Your custom snapshotter will be
+	// much more useful than using a snapshotter which is already included.
+	// https://godoc.org/github.com/containerd/containerd/snapshots#Snapshotter
+	sn, err := native.NewSnapshotter(os.Args[2])
+	if err != nil {
+		fmt.Printf("error: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Convert the snapshotter to a gRPC service,
+	// example in github.com/containerd/containerd/contrib/snapshotservice
+	service := snapshotservice.FromSnapshotter(sn)
+
+	// Register the service with the gRPC server
+	snapshotsapi.RegisterSnapshotsServer(rpc, service)
+
+	// Listen and serve
+	l, err := net.Listen("unix", os.Args[1])
+	if err != nil {
+		fmt.Printf("error: %v\n", err)
+		os.Exit(1)
+	}
+	if err := rpc.Serve(l); err != nil {
+		fmt.Printf("error: %v\n", err)
+		os.Exit(1)
+	}
+}
+```
+
+Using the previous configuration and example, you could run a snapshot plugin
+with
+```
+# Start plugin in one terminal
+$ go run ./main.go /var/run/mysnapshotter.sock /tmp/snapshots
+
+# Use ctr in another
+$ CONTAINERD_SNAPSHOTTER=customsnapshot ctr images pull docker.io/library/alpine:latest
+$ tree -L 3 /tmp/snapshots
+/tmp/snapshots
+|-- metadata.db
+`-- snapshots
+    `-- 1
+        |-- bin
+        |-- dev
+        |-- etc
+        |-- home
+        |-- lib
+        |-- media
+        |-- mnt
+        |-- proc
+        |-- root
+        |-- run
+        |-- sbin
+        |-- srv
+        |-- sys
+        |-- tmp
+        |-- usr
+        `-- var
+
+18 directories, 1 file
+```
+
+## Built-in Plugins
+
+containerd uses plugins internally to ensure that internal implementations are
+decoupled, stable, and treated equally with external plugins. To see all the
+plugins containerd has, use `ctr plugins ls`
+
+```
+$ ctr plugins ls
+TYPE                            ID                    PLATFORMS      STATUS
+io.containerd.content.v1        content               -              ok
+io.containerd.snapshotter.v1    btrfs                 linux/amd64    ok
+io.containerd.snapshotter.v1    aufs                  linux/amd64    error
+io.containerd.snapshotter.v1    native                linux/amd64    ok
+io.containerd.snapshotter.v1    overlayfs             linux/amd64    ok
+io.containerd.snapshotter.v1    zfs                   linux/amd64    error
+io.containerd.metadata.v1       bolt                  -              ok
+io.containerd.differ.v1         walking               linux/amd64    ok
+io.containerd.gc.v1             scheduler             -              ok
+io.containerd.service.v1        containers-service    -              ok
+io.containerd.service.v1        content-service       -              ok
+io.containerd.service.v1        diff-service          -              ok
+io.containerd.service.v1        images-service        -              ok
+io.containerd.service.v1        leases-service        -              ok
+io.containerd.service.v1        namespaces-service    -              ok
+io.containerd.service.v1        snapshots-service     -              ok
+io.containerd.runtime.v1        linux                 linux/amd64    ok
+io.containerd.runtime.v2        task                  linux/amd64    ok
+io.containerd.monitor.v1        cgroups               linux/amd64    ok
+io.containerd.service.v1        tasks-service         -              ok
+io.containerd.internal.v1       restart               -              ok
+io.containerd.grpc.v1           containers            -              ok
+io.containerd.grpc.v1           content               -              ok
+io.containerd.grpc.v1           diff                  -              ok
+io.containerd.grpc.v1           events                -              ok
+io.containerd.grpc.v1           healthcheck           -              ok
+io.containerd.grpc.v1           images                -              ok
+io.containerd.grpc.v1           leases                -              ok
+io.containerd.grpc.v1           namespaces            -              ok
+io.containerd.grpc.v1           snapshots             -              ok
+io.containerd.grpc.v1           tasks                 -              ok
+io.containerd.grpc.v1           version               -              ok
+io.containerd.grpc.v1           cri                   linux/amd64    ok
+```
+
+From the output all the plugins can be seen as well those which did not
+successfully load. In this case `aufs` and `zfs` are expected not to load
+since they are not support on the machine. The logs will show why it failed,
+but you can also get more details using the `-d` option.
+
+```
+$ ctr plugins ls -d id==aufs id==zfs
+Type:          io.containerd.snapshotter.v1
+ID:            aufs
+Platforms:     linux/amd64
+Exports:
+               root      /var/lib/containerd/io.containerd.snapshotter.v1.aufs
+Error:
+               Code:        Unknown
+               Message:     modprobe aufs failed: "modprobe: FATAL: Module aufs not found in directory /lib/modules/4.17.2-1-ARCH\n": exit status 1
+
+Type:          io.containerd.snapshotter.v1
+ID:            zfs
+Platforms:     linux/amd64
+Exports:
+               root      /var/lib/containerd/io.containerd.snapshotter.v1.zfs
+Error:
+               Code:        Unknown
+               Message:     path /var/lib/containerd/io.containerd.snapshotter.v1.zfs must be a zfs filesystem to be used with the zfs snapshotter
+```
+
+The error message which the plugin returned explains why the plugin was unable
+to load.
+
+#### Configuration
+
+Plugins are configured using the `[plugins]` section of containerd's config.
+Every plugin can have its own section using the pattern `[plugins.<plugin id>]`.
+
+example configuration
+```
+[plugins]
+  [plugins.cgroups]
+    no_prometheus = false
+  [plugins.cri]
+    stream_server_address = ""
+    stream_server_port = "10010"
+    enable_selinux = false
+    sandbox_image = "k8s.gcr.io/pause:3.1"
+    stats_collect_period = 10
+    systemd_cgroup = false
+    [plugins.cri.containerd]
+      snapshotter = "overlayfs"
+      [plugins.cri.containerd.default_runtime]
+        runtime_type = "io.containerd.runtime.v1.linux"
+        runtime_engine = ""
+        runtime_root = ""
+      [plugins.cri.containerd.untrusted_workload_runtime]
+        runtime_type = ""
+        runtime_engine = ""
+        runtime_root = ""
+    [plugins.cri.cni]
+      bin_dir = "/opt/cni/bin"
+      conf_dir = "/etc/cni/net.d"
+    [plugins.cri.registry]
+      [plugins.cri.registry.mirrors]
+        [plugins.cri.registry.mirrors."docker.io"]
+          endpoint = ["https://registry-1.docker.io"]
+```
diff --git a/README.md b/README.md
index 2130d68cf..74fa19c7f 100644
--- a/README.md
+++ b/README.md
@@ -184,6 +184,28 @@ defer task.Delete(context)
 err := task.Start(context)
 ```
 
+### Snapshot Plugins
+
+In addition to the built-in Snapshot plugins in containerd, additional external
+plugins can be configured using GRPC. An external plugin is made available using
+the configured name and appears as a plugin alongside the built-in ones.
+
+To add an external snapshot plugin, add the plugin to containerd's config file
+(by default at `/etc/containerd/config.toml`). The string following
+`proxy_plugin.` will be used as the name of the snapshotter and the address
+should refer to a socket with a GRPC listener serving containerd's Snapshot
+GRPC API. Remember to restart containerd for any configuration changes to take
+effect.
+
+```
+[proxy_plugins]
+  [proxy_plugins.customsnapshot]
+    type = "snapshot"
+    address =  "/var/run/mysnapshotter.sock"
+```
+
+See [PLUGINS.md](PLUGINS.md) for how to create plugins
+
 ### Releases and API Stability
 
 Please see [RELEASES.md](RELEASES.md) for details on versioning and stability
diff --git a/contrib/snapshotservice/service.go b/contrib/snapshotservice/service.go
new file mode 100644
index 000000000..aebc69ed2
--- /dev/null
+++ b/contrib/snapshotservice/service.go
@@ -0,0 +1,218 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package snapshotservice
+
+import (
+	"context"
+
+	snapshotsapi "github.com/containerd/containerd/api/services/snapshots/v1"
+	"github.com/containerd/containerd/api/types"
+	"github.com/containerd/containerd/errdefs"
+	"github.com/containerd/containerd/mount"
+	"github.com/containerd/containerd/snapshots"
+	ptypes "github.com/gogo/protobuf/types"
+)
+
+var empty = &ptypes.Empty{}
+
+type service struct {
+	sn snapshots.Snapshotter
+}
+
+// FromSnapshotter returns a Snapshot API server from a containerd snapshotter
+func FromSnapshotter(sn snapshots.Snapshotter) snapshotsapi.SnapshotsServer {
+	return service{sn: sn}
+}
+
+func (s service) Prepare(ctx context.Context, pr *snapshotsapi.PrepareSnapshotRequest) (*snapshotsapi.PrepareSnapshotResponse, error) {
+	var opts []snapshots.Opt
+	if pr.Labels != nil {
+		opts = append(opts, snapshots.WithLabels(pr.Labels))
+	}
+	mounts, err := s.sn.Prepare(ctx, pr.Key, pr.Parent, opts...)
+	if err != nil {
+		return nil, errdefs.ToGRPC(err)
+	}
+
+	return &snapshotsapi.PrepareSnapshotResponse{
+		Mounts: fromMounts(mounts),
+	}, nil
+}
+
+func (s service) View(ctx context.Context, pr *snapshotsapi.ViewSnapshotRequest) (*snapshotsapi.ViewSnapshotResponse, error) {
+	var opts []snapshots.Opt
+	if pr.Labels != nil {
+		opts = append(opts, snapshots.WithLabels(pr.Labels))
+	}
+	mounts, err := s.sn.View(ctx, pr.Key, pr.Parent, opts...)
+	if err != nil {
+		return nil, errdefs.ToGRPC(err)
+	}
+	return &snapshotsapi.ViewSnapshotResponse{
+		Mounts: fromMounts(mounts),
+	}, nil
+}
+
+func (s service) Mounts(ctx context.Context, mr *snapshotsapi.MountsRequest) (*snapshotsapi.MountsResponse, error) {
+	mounts, err := s.sn.Mounts(ctx, mr.Key)
+	if err != nil {
+		return nil, errdefs.ToGRPC(err)
+	}
+	return &snapshotsapi.MountsResponse{
+		Mounts: fromMounts(mounts),
+	}, nil
+}
+
+func (s service) Commit(ctx context.Context, cr *snapshotsapi.CommitSnapshotRequest) (*ptypes.Empty, error) {
+	var opts []snapshots.Opt
+	if cr.Labels != nil {
+		opts = append(opts, snapshots.WithLabels(cr.Labels))
+	}
+	if err := s.sn.Commit(ctx, cr.Name, cr.Key, opts...); err != nil {
+		return nil, errdefs.ToGRPC(err)
+	}
+
+	return empty, nil
+}
+
+func (s service) Remove(ctx context.Context, rr *snapshotsapi.RemoveSnapshotRequest) (*ptypes.Empty, error) {
+	if err := s.sn.Remove(ctx, rr.Key); err != nil {
+		return nil, errdefs.ToGRPC(err)
+	}
+
+	return empty, nil
+}
+
+func (s service) Stat(ctx context.Context, sr *snapshotsapi.StatSnapshotRequest) (*snapshotsapi.StatSnapshotResponse, error) {
+	info, err := s.sn.Stat(ctx, sr.Key)
+	if err != nil {
+		return nil, errdefs.ToGRPC(err)
+	}
+
+	return &snapshotsapi.StatSnapshotResponse{Info: fromInfo(info)}, nil
+}
+
+func (s service) Update(ctx context.Context, sr *snapshotsapi.UpdateSnapshotRequest) (*snapshotsapi.UpdateSnapshotResponse, error) {
+	info, err := s.sn.Update(ctx, toInfo(sr.Info), sr.UpdateMask.GetPaths()...)
+	if err != nil {
+		return nil, errdefs.ToGRPC(err)
+	}
+
+	return &snapshotsapi.UpdateSnapshotResponse{Info: fromInfo(info)}, nil
+}
+
+func (s service) List(sr *snapshotsapi.ListSnapshotsRequest, ss snapshotsapi.Snapshots_ListServer) error {
+	var (
+		buffer    []snapshotsapi.Info
+		sendBlock = func(block []snapshotsapi.Info) error {
+			return ss.Send(&snapshotsapi.ListSnapshotsResponse{
+				Info: block,
+			})
+		}
+	)
+	err := s.sn.Walk(ss.Context(), func(ctx context.Context, info snapshots.Info) error {
+		buffer = append(buffer, fromInfo(info))
+
+		if len(buffer) >= 100 {
+			if err := sendBlock(buffer); err != nil {
+				return err
+			}
+
+			buffer = buffer[:0]
+		}
+
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	if len(buffer) > 0 {
+		// Send remaining infos
+		if err := sendBlock(buffer); err != nil {
+			return err
+		}
+	}
+
+	return nil
+
+}
+
+func (s service) Usage(ctx context.Context, ur *snapshotsapi.UsageRequest) (*snapshotsapi.UsageResponse, error) {
+	usage, err := s.sn.Usage(ctx, ur.Key)
+	if err != nil {
+		return nil, errdefs.ToGRPC(err)
+	}
+
+	return &snapshotsapi.UsageResponse{
+		Inodes: usage.Inodes,
+		Size_:  usage.Size,
+	}, nil
+}
+
+func fromKind(kind snapshots.Kind) snapshotsapi.Kind {
+	if kind == snapshots.KindActive {
+		return snapshotsapi.KindActive
+	}
+	if kind == snapshots.KindView {
+		return snapshotsapi.KindView
+	}
+	return snapshotsapi.KindCommitted
+}
+
+func fromInfo(info snapshots.Info) snapshotsapi.Info {
+	return snapshotsapi.Info{
+		Name:      info.Name,
+		Parent:    info.Parent,
+		Kind:      fromKind(info.Kind),
+		CreatedAt: info.Created,
+		UpdatedAt: info.Updated,
+		Labels:    info.Labels,
+	}
+}
+
+func fromMounts(mounts []mount.Mount) []*types.Mount {
+	out := make([]*types.Mount, len(mounts))
+	for i, m := range mounts {
+		out[i] = &types.Mount{
+			Type:    m.Type,
+			Source:  m.Source,
+			Options: m.Options,
+		}
+	}
+	return out
+}
+
+func toInfo(info snapshotsapi.Info) snapshots.Info {
+	return snapshots.Info{
+		Name:    info.Name,
+		Parent:  info.Parent,
+		Kind:    toKind(info.Kind),
+		Created: info.CreatedAt,
+		Updated: info.UpdatedAt,
+		Labels:  info.Labels,
+	}
+}
+
+func toKind(kind snapshotsapi.Kind) snapshots.Kind {
+	if kind == snapshotsapi.KindActive {
+		return snapshots.KindActive
+	}
+	if kind == snapshotsapi.KindView {
+		return snapshots.KindView
+	}
+	return snapshots.KindCommitted
+}