diff --git a/gns3server/api/routes/controller/appliances.py b/gns3server/api/routes/controller/appliances.py
index 944b91c81..18532e052 100644
--- a/gns3server/api/routes/controller/appliances.py
+++ b/gns3server/api/routes/controller/appliances.py
@@ -18,11 +18,9 @@
 API routes for appliances.
 """
 
-import os
 import logging
 
 from fastapi import APIRouter, Depends, Response, status
-from fastapi.responses import FileResponse
 from typing import Optional, List
 from uuid import UUID
 
@@ -42,7 +40,10 @@ router = APIRouter()
 
 
 @router.get("")
-async def get_appliances(update: Optional[bool] = False, symbol_theme: Optional[str] = "Classic") -> List[dict]:
+async def get_appliances(
+        update: Optional[bool] = False,
+        symbol_theme: Optional[str] = "Classic"
+) -> List[schemas.Appliance]:
     """
     Return all appliances known by the controller.
     """
@@ -54,21 +55,17 @@ async def get_appliances(update: Optional[bool] = False, symbol_theme: Optional[
     return [c.asdict() for c in controller.appliance_manager.appliances.values()]
 
 
-@router.get("/{appliance_id}/download")
-def download_appliance(appliance_id: UUID) -> FileResponse:
+@router.get("/{appliance_id}")
+def get_appliance(appliance_id: UUID) -> schemas.Appliance:
     """
-    Download an appliance file.
+    Get an appliance file.
     """
 
     controller = Controller.instance()
     appliance = controller.appliance_manager.appliances.get(str(appliance_id))
     if not appliance:
         raise ControllerNotFoundError(message=f"Could not find appliance '{appliance_id}'")
-
-    if not os.path.exists(appliance.path):
-        raise ControllerNotFoundError(message=f"Could not find appliance file '{appliance.path}'")
-
-    return FileResponse(appliance.path, media_type="application/json")
+    return appliance.asdict()
 
 
 @router.post("/{appliance_id}/install", status_code=status.HTTP_204_NO_CONTENT)
diff --git a/gns3server/controller/appliance.py b/gns3server/controller/appliance.py
index c460e4e9f..9e93ee424 100644
--- a/gns3server/controller/appliance.py
+++ b/gns3server/controller/appliance.py
@@ -16,7 +16,6 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import copy
-import uuid
 import logging
 
 log = logging.getLogger(__name__)
@@ -27,12 +26,9 @@ class Appliance:
     def __init__(self, path, data, builtin=True):
 
         self._data = data.copy()
-        self._id = data.get("appliance_id", uuid.uuid5(uuid.NAMESPACE_X500, path))
+        self._id = self._data.get("appliance_id")
         self._path = path
         self._builtin = builtin
-        if "appliance_id" in self._data:
-            del self._data["appliance_id"]
-
         if self.status != "broken":
             log.debug(f'Appliance "{self.name}" [{self._id}] loaded')
 
@@ -84,6 +80,7 @@ class Appliance:
         """
         Appliance data (a hash)
         """
+
         data = copy.deepcopy(self._data)
         data["builtin"] = self._builtin
         return data
diff --git a/gns3server/controller/appliance_manager.py b/gns3server/controller/appliance_manager.py
index d837abe23..c00b26fd8 100644
--- a/gns3server/controller/appliance_manager.py
+++ b/gns3server/controller/appliance_manager.py
@@ -214,6 +214,10 @@ class ApplianceManager:
 
         appliances_info = self._find_appliances_from_image_checksum(image_checksum)
         for appliance, image_version in appliances_info:
+            try:
+                schemas.Appliance.parse_obj(appliance.asdict())
+            except ValidationError as e:
+                log.warning(message=f"Could not validate appliance '{appliance.id}': {e}")
             if appliance.versions:
                 for version in appliance.versions:
                     if version.get("name") == image_version:
@@ -241,6 +245,11 @@ class ApplianceManager:
         if not appliance:
             raise ControllerNotFoundError(message=f"Could not find appliance '{appliance_id}'")
 
+        try:
+            schemas.Appliance.parse_obj(appliance.asdict())
+        except ValidationError as e:
+            raise ControllerError(message=f"Could not validate appliance '{appliance_id}': {e}")
+
         if version:
             if not appliance.versions:
                 raise ControllerBadRequestError(message=f"Appliance '{appliance_id}' do not have versions")
@@ -289,16 +298,18 @@ class ApplianceManager:
                     path = os.path.join(directory, file)
                     try:
                         with open(path, encoding="utf-8") as f:
-                            appliance = Appliance(path, json.load(f), builtin=builtin)
-                            json_data = appliance.asdict()  # Check if loaded without error
+                            json_data = json.load(f)
+                            schemas.Appliance.parse_obj(json_data)
+                            appliance = Appliance(path, json_data, builtin=builtin)
+                            appliance_data = appliance.asdict()  # Check if loaded without error
                             if appliance.status != "broken":
                                 self._appliances[appliance.id] = appliance
                             if not appliance.symbol or appliance.symbol.startswith(":/symbols/"):
                                 # apply a default symbol if the appliance has none or a default symbol
-                                default_symbol = self._get_default_symbol(json_data, symbol_theme)
+                                default_symbol = self._get_default_symbol(appliance_data, symbol_theme)
                                 if default_symbol:
                                     appliance.symbol = default_symbol
-                    except (ValueError, OSError, KeyError) as e:
+                    except (ValueError, OSError, KeyError, ValidationError) as e:
                         log.warning(f"Cannot load appliance file '{path}': {e}")
                         continue
 
diff --git a/gns3server/schemas/__init__.py b/gns3server/schemas/__init__.py
index 477c9058d..f5c69e320 100644
--- a/gns3server/schemas/__init__.py
+++ b/gns3server/schemas/__init__.py
@@ -24,6 +24,7 @@ from .controller.links import LinkCreate, LinkUpdate, Link
 from .controller.computes import ComputeCreate, ComputeUpdate, AutoIdlePC, Compute
 from .controller.templates import TemplateCreate, TemplateUpdate, TemplateUsage, Template
 from .controller.images import Image, ImageType
+from .controller.appliances import Appliance
 from .controller.drawings import Drawing
 from .controller.gns3vm import GNS3VM
 from .controller.nodes import NodeCreate, NodeUpdate, NodeDuplicate, NodeCapture, Node
diff --git a/gns3server/schemas/controller/appliances.py b/gns3server/schemas/controller/appliances.py
new file mode 100644
index 000000000..604af3f75
--- /dev/null
+++ b/gns3server/schemas/controller/appliances.py
@@ -0,0 +1,463 @@
+#
+# Copyright (C) 2021 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from enum import Enum
+from typing import List, Optional, Union
+from uuid import UUID
+
+from pydantic import AnyUrl, BaseModel, EmailStr, Field, confloat, conint, constr
+
+
+class Category(Enum):
+
+    router = 'router'
+    multilayer_switch = 'multilayer_switch'
+    switch = 'switch'
+    firewall = 'firewall'
+    guest = 'guest'
+
+
+class RegistryVersion(Enum):
+
+    version1 = 1
+    version2 = 2
+    version3 = 3
+    version4 = 4
+    version5 = 5
+    version6 = 6
+
+
+class Status(Enum):
+
+    stable = 'stable'
+    experimental = 'experimental'
+    broken = 'broken'
+
+
+class Availability(Enum):
+
+    free = 'free'
+    with_registration = 'with-registration'
+    free_to_try = 'free-to-try'
+    service_contract = 'service-contract'
+
+
+class ConsoleType(Enum):
+
+    telnet = 'telnet'
+    vnc = 'vnc'
+    http = 'http'
+    https = 'https'
+    none = 'none'
+
+
+class Docker(BaseModel):
+
+    adapters: int = Field(..., title='Number of ethernet adapters')
+    image: str = Field(..., title='Docker image in the Docker Hub')
+    start_command: Optional[str] = Field(
+        None,
+        title='Command executed when the container start. Empty will use the default',
+    )
+    environment: Optional[str] = Field(None, title='One KEY=VAR environment by line')
+    console_type: Optional[ConsoleType] = Field(
+        None, title='Type of console connection for the administration of the appliance'
+    )
+    console_http_port: Optional[int] = Field(
+        None, description='Internal port in the container of the HTTP server'
+    )
+    console_http_path: Optional[str] = Field(
+        None, description='Path of the web interface'
+    )
+    extra_hosts: Optional[str] = Field(
+        None, description='Hosts which will be written to /etc/hosts into container'
+    )
+    extra_volumes: Optional[List[str]] = Field(
+        None,
+        description='Additional directories to make persistent that are not included in the images VOLUME directive',
+    )
+
+
+class Iou(BaseModel):
+
+    ethernet_adapters: int = Field(..., title='Number of ethernet adapters')
+    serial_adapters: int = Field(..., title='Number of serial adapters')
+    nvram: int = Field(..., title='Host NVRAM')
+    ram: int = Field(..., title='Host RAM')
+    startup_config: str = Field(..., title='Config loaded at startup')
+
+
+class Chassis(Enum):
+
+    chassis_1720 = '1720'
+    chassis_1721 = '1721'
+    chassis_1750 = '1750'
+    chassis_1751 = '1751'
+    chassis_1760 = '1760'
+    chassis_2610 = '2610'
+    chassis_2620 = '2620'
+    chassis_2610XM = '2610XM'
+    chassis_2620XM = '2620XM'
+    chassis_2650XM = '2650XM'
+    chassis_2621 = '2621'
+    chassis_2611XM = '2611XM'
+    chassis_2621XM = '2621XM'
+    chassis_2651XM = '2651XM'
+    chassis_3620 = '3620'
+    chassis_3640 = '3640'
+    chassis_3660 = '3660'
+
+
+class Platform(Enum):
+
+    c1700 = 'c1700'
+    c2600 = 'c2600'
+    c2691 = 'c2691'
+    c3725 = 'c3725'
+    c3745 = 'c3745'
+    c3600 = 'c3600'
+    c7200 = 'c7200'
+
+
+class Midplane(Enum):
+
+    std = 'std'
+    vxr = 'vxr'
+
+
+class Npe(Enum):
+
+    npe_100 = 'npe-100'
+    npe_150 = 'npe-150'
+    npe_175 = 'npe-175'
+    npe_200 = 'npe-200'
+    npe_225 = 'npe-225'
+    npe_300 = 'npe-300'
+    npe_400 = 'npe-400'
+    npe_g2 = 'npe-g2'
+
+
+class AdapterType(Enum):
+
+    e1000 = 'e1000'
+    e1000_82544gc = 'e1000-82544gc'
+    e1000_82545em = 'e1000-82545em'
+    e1000e = 'e1000e'
+    i82550 = 'i82550'
+    i82551 = 'i82551'
+    i82557a = 'i82557a'
+    i82557b = 'i82557b'
+    i82557c = 'i82557c'
+    i82558a = 'i82558a'
+    i82558b = 'i82558b'
+    i82559a = 'i82559a'
+    i82559b = 'i82559b'
+    i82559c = 'i82559c'
+    i82559er = 'i82559er'
+    i82562 = 'i82562'
+    i82801 = 'i82801'
+    ne2k_pci = 'ne2k_pci'
+    pcnet = 'pcnet'
+    rocker = 'rocker'
+    rtl8139 = 'rtl8139'
+    virtio = 'virtio'
+    virtio_net_pci = 'virtio-net-pci'
+    vmxnet3 = 'vmxnet3'
+
+
+class DiskInterface(Enum):
+
+    ide = 'ide'
+    sata = 'sata'
+    nvme = 'nvme'
+    scsi = 'scsi'
+    sd = 'sd'
+    mtd = 'mtd'
+    floppy = 'floppy'
+    pflash = 'pflash'
+    virtio = 'virtio'
+    none = 'none'
+
+
+class Arch(Enum):
+
+    aarch64 = 'aarch64'
+    alpha = 'alpha'
+    arm = 'arm'
+    cris = 'cris'
+    i386 = 'i386'
+    lm32 = 'lm32'
+    m68k = 'm68k'
+    microblaze = 'microblaze'
+    microblazeel = 'microblazeel'
+    mips = 'mips'
+    mips64 = 'mips64'
+    mips64el = 'mips64el'
+    mipsel = 'mipsel'
+    moxie = 'moxie'
+    or32 = 'or32'
+    ppc = 'ppc'
+    ppc64 = 'ppc64'
+    ppcemb = 'ppcemb'
+    s390x = 's390x'
+    sh4 = 'sh4'
+    sh4eb = 'sh4eb'
+    sparc = 'sparc'
+    sparc64 = 'sparc64'
+    tricore = 'tricore'
+    unicore32 = 'unicore32'
+    x86_64 = 'x86_64'
+    xtensa = 'xtensa'
+    xtensaeb = 'xtensaeb'
+
+
+class ConsoleType1(Enum):
+
+    telnet = 'telnet'
+    vnc = 'vnc'
+    spice = 'spice'
+    spice_agent = 'spice+agent'
+    none = 'none'
+
+
+class BootPriority(Enum):
+
+    c = 'c'
+    d = 'd'
+    n = 'n'
+    cn = 'cn'
+    cd = 'cd'
+    dn = 'dn'
+    dc = 'dc'
+    nc = 'nc'
+    nd = 'nd'
+
+
+class Kvm(Enum):
+
+    require = 'require'
+    allow = 'allow'
+    disable = 'disable'
+
+
+class ProcessPriority(Enum):
+
+    realtime = 'realtime'
+    very_high = 'very high'
+    high = 'high'
+    normal = 'normal'
+    low = 'low'
+    very_low = 'very low'
+    null = 'null'
+
+
+class Qemu(BaseModel):
+
+    adapter_type: AdapterType = Field(..., title='Type of network adapter')
+    adapters: int = Field(..., title='Number of adapters')
+    ram: int = Field(..., title='Ram allocated to the appliance (MB)')
+    cpus: Optional[int] = Field(None, title='Number of Virtual CPU')
+    hda_disk_interface: Optional[DiskInterface] = Field(
+        None, title='Disk interface for the installed hda_disk_image'
+    )
+    hdb_disk_interface: Optional[DiskInterface] = Field(
+        None, title='Disk interface for the installed hdb_disk_image'
+    )
+    hdc_disk_interface: Optional[DiskInterface] = Field(
+        None, title='Disk interface for the installed hdc_disk_image'
+    )
+    hdd_disk_interface: Optional[DiskInterface] = Field(
+        None, title='Disk interface for the installed hdd_disk_image'
+    )
+    arch: Arch = Field(..., title='Architecture emulated')
+    console_type: ConsoleType1 = Field(
+        ..., title='Type of console connection for the administration of the appliance'
+    )
+    boot_priority: Optional[BootPriority] = Field(
+        None,
+        title='Disk boot priority. Refer to -boot option in qemu manual for more details.',
+    )
+    kernel_command_line: Optional[str] = Field(
+        None, title='Command line parameters send to the kernel'
+    )
+    kvm: Kvm = Field(..., title='KVM requirements')
+    options: Optional[str] = Field(
+        None, title='Optional additional qemu command line options'
+    )
+    cpu_throttling: Optional[confloat(ge=0.0, le=100.0)] = Field(
+        None, title='Throttle the CPU'
+    )
+    process_priority: Optional[ProcessPriority] = Field(
+        None, title='Process priority for QEMU'
+    )
+
+
+class Compression(Enum):
+
+    bzip2 = 'bzip2'
+    gzip = 'gzip'
+    lzma = 'lzma'
+    xz = 'xz'
+    rar = 'rar'
+    zip = 'zip'
+    field_7z = '7z'
+
+
+class Image(BaseModel):
+
+    filename: str = Field(..., title='Filename')
+    version: str = Field(..., title='Version of the file')
+    md5sum: constr(regex=r'^[a-f0-9]{32}$') = Field(..., title='md5sum of the file')
+    filesize: int = Field(..., title='File size in bytes')
+    download_url: Optional[Union[AnyUrl, constr(max_length=0)]] = Field(
+        None, title='Download url where you can download the appliance from a browser'
+    )
+    direct_download_url: Optional[Union[AnyUrl, constr(max_length=0)]] = Field(
+        None,
+        title='Optional. Non authenticated url to the image file where you can download the image.',
+    )
+    compression: Optional[Compression] = Field(
+        None, title='Optional, compression type of direct download url image.'
+    )
+
+
+class Images(BaseModel):
+
+    kernel_image: Optional[str] = Field(None, title='Kernel image')
+    initrd: Optional[str] = Field(None, title='Initrd disk image')
+    image: Optional[str] = Field(None, title='OS image')
+    bios_image: Optional[str] = Field(None, title='Bios image')
+    hda_disk_image: Optional[str] = Field(None, title='Hda disk image')
+    hdb_disk_image: Optional[str] = Field(None, title='Hdc disk image')
+    hdc_disk_image: Optional[str] = Field(None, title='Hdd disk image')
+    hdd_disk_image: Optional[str] = Field(None, title='Hdd diskimage')
+    cdrom_image: Optional[str] = Field(None, title='cdrom image')
+
+
+class Version(BaseModel):
+
+    name: str = Field(..., title='Name of the version')
+    idlepc: Optional[constr(regex=r'^0x[0-9a-f]{8}')] = None
+    images: Optional[Images] = Field(None, title='Images used for this version')
+
+
+class DynamipsSlot(Enum):
+
+    C7200_IO_2FE = 'C7200-IO-2FE'
+    C7200_IO_FE = 'C7200-IO-FE'
+    C7200_IO_GE_E = 'C7200-IO-GE-E'
+    NM_16ESW = 'NM-16ESW'
+    NM_1E = 'NM-1E'
+    NM_1FE_TX = 'NM-1FE-TX'
+    NM_4E = 'NM-4E'
+    NM_4T = 'NM-4T'
+    PA_2FE_TX = 'PA-2FE-TX'
+    PA_4E = 'PA-4E'
+    PA_4T_ = 'PA-4T+'
+    PA_8E = 'PA-8E'
+    PA_8T = 'PA-8T'
+    PA_A1 = 'PA-A1'
+    PA_FE_TX = 'PA-FE-TX'
+    PA_GE = 'PA-GE'
+    PA_POS_OC3 = 'PA-POS-OC3'
+    C2600_MB_2FE = 'C2600-MB-2FE'
+    C2600_MB_1E = 'C2600-MB-1E'
+    C1700_MB_1FE = 'C1700-MB-1FE'
+    C2600_MB_2E = 'C2600-MB-2E'
+    C2600_MB_1FE = 'C2600-MB-1FE'
+    C1700_MB_WIC1 = 'C1700-MB-WIC1'
+    GT96100_FE = 'GT96100-FE'
+    Leopard_2FE = 'Leopard-2FE'
+    _ = ''
+
+
+class DynamipsWic(Enum):
+
+    WIC_1ENET = 'WIC-1ENET'
+    WIC_1T = 'WIC-1T'
+    WIC_2T = 'WIC-2T'
+
+
+class Dynamips(BaseModel):
+
+    chassis: Optional[Chassis] = Field(None, title='Chassis type')
+    platform: Platform = Field(..., title='Platform type')
+    ram: conint(ge=1) = Field(..., title='Amount of ram')
+    nvram: conint(ge=1) = Field(..., title='Amount of nvram')
+    startup_config: Optional[str] = Field(None, title='Config loaded at startup')
+    wic0: Optional[DynamipsWic] = None
+    wic1: Optional[DynamipsWic] = None
+    wic2: Optional[DynamipsWic] = None
+    slot0: Optional[DynamipsSlot] = None
+    slot1: Optional[DynamipsSlot] = None
+    slot2: Optional[DynamipsSlot] = None
+    slot3: Optional[DynamipsSlot] = None
+    slot4: Optional[DynamipsSlot] = None
+    slot5: Optional[DynamipsSlot] = None
+    slot6: Optional[DynamipsSlot] = None
+    midplane: Optional[Midplane] = None
+    npe: Optional[Npe] = None
+
+
+class Appliance(BaseModel):
+
+    appliance_id: UUID = Field(..., title='Appliance ID')
+    name: str = Field(..., title='Appliance name')
+    category: Category = Field(..., title='Category of the appliance')
+    description: str = Field(
+        ..., title='Description of the appliance. Could be a marketing description'
+    )
+    vendor_name: str = Field(..., title='Name of the vendor')
+    vendor_url: Union[AnyUrl, constr(max_length=0)] = Field(..., title='Website of the vendor')
+    documentation_url: Optional[Union[AnyUrl, constr(max_length=0)]] = Field(
+        None,
+        title='An optional documentation for using the appliance on vendor website',
+    )
+    product_name: str = Field(..., title='Product name')
+    product_url: Optional[Union[AnyUrl, constr(max_length=0)]] = Field(
+        None, title='An optional product url on vendor website'
+    )
+    registry_version: RegistryVersion = Field(
+        ..., title='Version of the registry compatible with this appliance'
+    )
+    status: Status = Field(..., title='Document if the appliance is working or not')
+    availability: Optional[Availability] = Field(
+        None,
+        title='About image availability: can be downloaded directly; download requires a free registration; paid but a trial version (time or feature limited) is available; not available publicly',
+    )
+    maintainer: str = Field(..., title='Maintainer name')
+    maintainer_email: Union[EmailStr, constr(max_length=0)] = Field(..., title='Maintainer email')
+    usage: Optional[str] = Field(None, title='How to use the appliance')
+    symbol: Optional[str] = Field(None, title='An optional symbol for the appliance')
+    first_port_name: Optional[str] = Field(
+        None, title='Optional name of the first networking port example: eth0'
+    )
+    port_name_format: Optional[str] = Field(
+        None, title='Optional formating of the networking port example: eth{0}'
+    )
+    port_segment_size: Optional[int] = Field(
+        None,
+        title='Optional port segment size. A port segment is a block of port. For example Ethernet0/0 Ethernet0/1 is the module 0 with a port segment size of 2',
+    )
+    linked_clone: Optional[bool] = Field(
+        None, title="False if you don't want to use a single image for all nodes"
+    )
+    docker: Optional[Docker] = Field(None, title='Docker specific options')
+    iou: Optional[Iou] = Field(None, title='IOU specific options')
+    dynamips: Optional[Dynamips] = Field(None, title='Dynamips specific options')
+    qemu: Optional[Qemu] = Field(None, title='Qemu specific options')
+    images: Optional[List[Image]] = Field(None, title='Images for this appliance')
+    versions: Optional[List[Version]] = Field(None, title='Versions of the appliance')
diff --git a/tests/api/routes/controller/test_appliances.py b/tests/api/routes/controller/test_appliances.py
index 53fcc73b8..a57b04adc 100644
--- a/tests/api/routes/controller/test_appliances.py
+++ b/tests/api/routes/controller/test_appliances.py
@@ -33,10 +33,10 @@ class TestApplianceRoutes:
         assert response.status_code == status.HTTP_200_OK
         assert len(response.json()) > 0
 
-    async def test_appliance_download(self, app: FastAPI, client: AsyncClient) -> None:
+    async def test_get_appliance(self, app: FastAPI, client: AsyncClient) -> None:
 
         appliance_id = "3bf492b6-5717-4257-9bfd-b34617c6f133"  # Cisco IOSv appliance
-        response = await client.get(app.url_path_for("download_appliance", appliance_id=appliance_id))
+        response = await client.get(app.url_path_for("get_appliance", appliance_id=appliance_id))
         assert response.status_code == status.HTTP_200_OK
         assert response.json()["appliance_id"] == appliance_id