diff --git a/src/types/dbTypes.ts b/src/types/dbTypes.ts
new file mode 100644
index 0000000..6f5a395
--- /dev/null
+++ b/src/types/dbTypes.ts
@@ -0,0 +1,27 @@
+import { Device } from '../models/Device'
+import { DeviceState, PushEvent, PushEventState } from './pushTypes'
+
+export interface DeviceRow {
+  device: Device
+
+  updateEvents: (events: PushEvent[]) => Promise<void>
+  updateState: (state: DeviceState) => Promise<void>
+}
+
+export interface PushEventRow {
+  event: PushEvent
+
+  updateState: (state: PushEventState) => Promise<void>
+}
+
+export interface DbConnection {
+  // Background event watchers:
+  streamAddressBalanceEvents: () => Promise<AsyncIterableIterator<PushEventRow>>
+  streamPriceEvents: () => Promise<AsyncIterableIterator<PushEventRow>>
+  streamTxConfirmEvents: () => Promise<AsyncIterableIterator<PushEventRow>>
+
+  // Queries:
+  getDeviceById: (deviceId: string) => Promise<DeviceRow>
+  getEventsByDeviceId: (deviceId: string) => Promise<PushEventRow[]>
+  getEventsByLoginId: (loginId: Uint8Array) => Promise<PushEventRow[]>
+}
diff --git a/src/types/pushTypes.ts b/src/types/pushTypes.ts
index 979fcb8..e03f506 100644
--- a/src/types/pushTypes.ts
+++ b/src/types/pushTypes.ts
@@ -28,3 +28,93 @@ export interface ApiKey {
   admin: boolean
   adminsdk?: FirebaseAdminKey
 }
+
+/**
+ * Mutable state on a device object.
+ */
+export interface DeviceState {
+  enableLegacyPrices: boolean // For legacy v1 API.
+  rootLoginIds: Uint8Array[] // asArray(asBase64)
+  visited: Date
+}
+
+/**
+ * An app installed on a single phone.
+ */
+export interface Device extends DeviceState {
+  readonly appId: string
+  readonly created: Date
+  readonly deviceId: string
+  readonly deviceToken: string
+}
+
+//
+// Events that devices or logins may subscribe to.
+//
+
+export interface AddressBalanceTrigger {
+  readonly type: 'address-balance'
+  readonly pluginId: string
+  readonly tokenId?: string
+  readonly address: string
+  readonly aboveAmount?: string // Satoshis or Wei or such
+  readonly belowAmount?: string // Satoshis or Wei or such
+}
+
+export interface PriceChangeTrigger {
+  readonly type: 'price-change'
+  readonly pluginId: string
+  readonly tokenId?: string
+  readonly dailyChange?: number // Percentage
+  readonly hourlyChange?: number // Percentage
+}
+
+export interface PriceLevelTrigger {
+  readonly type: 'price-level'
+  readonly currencyPair: string // From our rates server
+  readonly aboveRate?: number
+  readonly belowRate?: number
+}
+
+export interface TxConfirmTrigger {
+  readonly type: 'tx-confirm'
+  readonly pluginId: string
+  readonly confirmations: number
+  readonly txid: string
+}
+
+export type PushTrigger =
+  | AddressBalanceTrigger
+  | PriceChangeTrigger
+  | PriceLevelTrigger
+  | TxConfirmTrigger
+
+/**
+ * Mutable flags that we can toggle on a push event.
+ */
+export interface PushEventState {
+  active: boolean // Watch the trigger when true
+  triggered?: Date
+  broadcasted?: Date
+  pushed?: Date
+}
+
+/**
+ * An action to perform once a trigger takes place.
+ */
+export interface PushEvent extends PushEventState {
+  readonly eventId?: string
+  readonly deviceId?: string
+  readonly loginId?: Uint8Array
+
+  readonly broadcast?: Array<{
+    pluginId: string
+    rawTx: Uint8Array // asBase64
+  }>
+  readonly push?: {
+    title?: string
+    body?: string
+    data: { [key: string]: string } // JSON to push to device
+  }
+  readonly trigger: PushTrigger
+}
diff --git a/src/types/v2Types.ts b/src/types/v2Types.ts
new file mode 100644
index 0000000..7fb436e
--- /dev/null
+++ b/src/types/v2Types.ts
@@ -0,0 +1,125 @@
+export interface Device {
+  appId: string
+  deviceId: string
+  deviceToken: string
+  rootLoginIds: Uint8Array[] // asArray(asBase64)
+  created: Date
+  visited: Date
+}
+
+interface PriceChangeTrigger {
+  type: 'price-change'
+  pluginId: string
+  tokenId?: string
+  aboveRatio?: number //  1.1 for +10%
+  belowRatio?: number // 0.9 for -10%
+  range: 'hourly' | 'daily'
+}
+
+interface PriceLevelTrigger {
+  type: 'price-level'
+  currencyPair: string // From our rates server
+  aboveRate?: number
+  belowRate?: number
+}
+
+interface AddressBalanceTrigger {
+  type: 'address-balance'
+  pluginId: string
+  tokenId?: string
+  address: string
+  aboveAmount?: string // Satoshis or Wei or such
+  belowAmount?: string // Satoshis or Wei or such
+}
+
+interface TxConfirmTrigger {
+  type: 'tx-confirm'
+  pluginId: string
+  confirmations: number
+  txid: string
+}
+
+export type PushTrigger =
+  | AddressBalanceTrigger
+  | PriceChangeTrigger
+  | PriceLevelTrigger
+  | TxConfirmTrigger
+
+interface PushEvent {
+  trigger: PushTrigger
+  triggered: boolean
+
+  // TODO: Check firebase docs
+  pushMessage?: string
+  pushPayload?: unknown // JSON to push to device
+  broadcastTxs?: Array<{
+    pluginId: string
+    rawTx: Uint8Array // asBase64
+  }>
+}
+
+export interface PushRequestBody {
+  // The request payload:
+  data: unknown
+
+  // Who is making the request:
+  apiKey: string
+  appId: string
+  deviceId: string
+
+  // For logins:
+  rootLoginId?: Uint8Array
+  // rootSecretHash?: Uint8Array
+}
+
+/**
+ * Refreshes the `visited` date on a device and its effects or logins.
+ * Devices expire after 3 months.
+ * POST /v2/device/checkin
+ */
+
+/**
+ * Registers / updates a device.
+ * POST /v2/device/update
+ */
+export interface UpdateDevicePayload {
+  rootLoginIds: Uint8Array[] // asArray(asBase64)
+  events: PushEvent[]
+  deviceToken: string
+}
+
+/**
+ * Gets a device from the database.
+ * POST /v2/device
+ */
+export interface DevicePayload {
+  deviceId: string
+  deviceToken: string
+  events: PushEvent[]
+  rootLoginIds: Uint8Array[] // asArray(asBase64)
+  created: Date
+  visited: Date
+}
+
+/**
+ * Registers / updates a login.
+ * POST /v2/login/update
+ */
+export interface UpdateLoginPayload {
+  events: PushEvent[]
+
+  // removeEvents?: string[]
+  // replaceEvents?: PushEvent[]
+  // newEvents?: PushEvent[]
+}
+
+/**
+ * Reads a login from the database.
+ * POST /v2/login
+ */
+export interface LoginPayload {
+  deviceIds: string
+  events: PushEvent[]
+  created: Date
+  visited: Date
+}