diff --git a/MIGRATION.md b/MIGRATION.md
index 9c2663c05b46..9a27dd6f3f26 100644
--- a/MIGRATION.md
+++ b/MIGRATION.md
@@ -292,6 +292,32 @@ changes in v7. They will be removed in the next major release which is why we st
 corresponding string literals. Here's how to adjust [`Severity`](#severity-severitylevel-and-severitylevels) and
 [`SpanStatus`](#spanstatus).
 
+## Session Changes
+
+Note: These changes are not relevant for the majority of Sentry users but if you are building an
+SDK on top of the Javascript SDK, you might need to make some adaptions.
+The internal `Session` class was refactored and replaced with a more functional approach in
+[#5054](https://github.com/getsentry/sentry-javascript/pull/5054).
+Instead of the class, we now export a `Session` interface from `@sentry/types` and three utility functions
+to create and update a `Session` object from `@sentry/hub`.
+This short example shows what has changed and how to deal with the new functions:
+
+```js
+// New in v7:
+import { makeSession, updateSession, closeSession } from '@sentry/hub';
+
+const session = makeSession({ release: 'v1.0' });
+updateSession(session, { environment: 'prod' });
+closeSession(session, 'ok');
+
+// Before:
+import { Session } from '@sentry/hub';
+
+const session = new Session({ release: 'v1.0' });
+session.update({ environment: 'prod' });
+session.close('ok');
+```
+
 ## General API Changes
 
 For our efforts to reduce bundle size of the SDK we had to remove and refactor parts of the package which introduced a few changes to the API:
@@ -313,7 +339,11 @@ For our efforts to reduce bundle size of the SDK we had to remove and refactor p
 - Rename `UserAgent` integration to `HttpContext`. (see [#5027](https://github.com/getsentry/sentry-javascript/pull/5027))
 - Remove `SDK_NAME` export from `@sentry/browser`, `@sentry/node`, `@sentry/tracing` and `@sentry/vue` packages.
 - Removed `eventStatusFromHttpCode` to save on bundle size.
+<<<<<<< HEAD
 - Replace `BrowserTracing` `maxTransactionDuration` option with `finalTimeout` option
+- Replace `Session` class with a session object and functions (see [#5054](https://github.com/getsentry/sentry-javascript/pull/5054)).
+=======
+>>>>>>> 5c81e32c4 (Add "Session Changes" section to Migration docs)
 
 ## Sentry Angular SDK Changes
 
diff --git a/packages/browser/src/exports.ts b/packages/browser/src/exports.ts
index ac3cea82190d..fd8ff9842a22 100644
--- a/packages/browser/src/exports.ts
+++ b/packages/browser/src/exports.ts
@@ -13,6 +13,7 @@ export type {
   Stacktrace,
   Thread,
   User,
+  Session,
 } from '@sentry/types';
 
 export type { BrowserOptions } from './client';
@@ -31,7 +32,6 @@ export {
   Hub,
   makeMain,
   Scope,
-  Session,
   startTransaction,
   SDK_VERSION,
   setContext,
diff --git a/packages/core/src/baseclient.ts b/packages/core/src/baseclient.ts
index 3c961218ca8d..f64f2b11d114 100644
--- a/packages/core/src/baseclient.ts
+++ b/packages/core/src/baseclient.ts
@@ -1,5 +1,5 @@
 /* eslint-disable max-lines */
-import { Scope, Session } from '@sentry/hub';
+import { Scope, updateSession } from '@sentry/hub';
 import {
   Client,
   ClientOptions,
@@ -12,6 +12,7 @@ import {
   Integration,
   IntegrationClass,
   Outcome,
+  Session,
   SessionAggregates,
   Severity,
   SeverityLevel,
@@ -199,7 +200,7 @@ export abstract class BaseClient<O extends ClientOptions> implements Client<O> {
     } else {
       this.sendSession(session);
       // After sending, we set init false to indicate it's not the first occurrence
-      session.update({ init: false });
+      updateSession(session, { init: false });
     }
   }
 
@@ -343,7 +344,7 @@ export abstract class BaseClient<O extends ClientOptions> implements Client<O> {
     const shouldUpdateAndSend = (sessionNonTerminal && session.errors === 0) || (sessionNonTerminal && crashed);
 
     if (shouldUpdateAndSend) {
-      session.update({
+      updateSession(session, {
         ...(crashed && { status: 'crashed' }),
         errors: session.errors || Number(errored || crashed),
       });
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 9e4afbbc86d0..0d1a686b8e5e 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -20,7 +20,6 @@ export {
   Hub,
   makeMain,
   Scope,
-  Session,
 } from '@sentry/hub';
 export { getEnvelopeEndpointWithUrlEncodedAuth, getReportDialogEndpoint } from './api';
 export { BaseClient } from './baseclient';
diff --git a/packages/core/test/lib/base.test.ts b/packages/core/test/lib/base.test.ts
index 520cd40931a6..7a5431d1f9cb 100644
--- a/packages/core/test/lib/base.test.ts
+++ b/packages/core/test/lib/base.test.ts
@@ -1,4 +1,4 @@
-import { Hub, Scope, Session } from '@sentry/hub';
+import { Hub, makeSession, Scope } from '@sentry/hub';
 import { Event, Span } from '@sentry/types';
 import { dsnToString, logger, SentryError, SyncPromise } from '@sentry/utils';
 
@@ -1327,7 +1327,7 @@ describe('BaseClient', () => {
 
       const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN });
       const client = new TestClient(options);
-      const session = new Session({ release: 'test' });
+      const session = makeSession({ release: 'test' });
 
       client.captureSession(session);
 
@@ -1339,7 +1339,7 @@ describe('BaseClient', () => {
 
       const options = getDefaultTestClientOptions({ enabled: false, dsn: PUBLIC_DSN });
       const client = new TestClient(options);
-      const session = new Session({ release: 'test' });
+      const session = makeSession({ release: 'test' });
 
       client.captureSession(session);
 
diff --git a/packages/core/test/mocks/client.ts b/packages/core/test/mocks/client.ts
index d46eb000d480..9caef7b0e0cf 100644
--- a/packages/core/test/mocks/client.ts
+++ b/packages/core/test/mocks/client.ts
@@ -1,5 +1,4 @@
-import { Session } from '@sentry/hub';
-import { ClientOptions, Event, Integration, Outcome, Severity, SeverityLevel } from '@sentry/types';
+import { ClientOptions, Event, Integration, Outcome, Session, Severity, SeverityLevel } from '@sentry/types';
 import { resolvedSyncPromise } from '@sentry/utils';
 
 import { BaseClient } from '../../src/baseclient';
diff --git a/packages/hub/src/hub.ts b/packages/hub/src/hub.ts
index ac98e053faf5..7f591e44c2e8 100644
--- a/packages/hub/src/hub.ts
+++ b/packages/hub/src/hub.ts
@@ -12,6 +12,7 @@ import {
   Integration,
   IntegrationClass,
   Primitive,
+  Session,
   SessionContext,
   Severity,
   SeverityLevel,
@@ -31,7 +32,7 @@ import {
 
 import { IS_DEBUG_BUILD } from './flags';
 import { Scope } from './scope';
-import { Session } from './session';
+import { closeSession, makeSession, updateSession } from './session';
 
 /**
  * API compatibility version of this hub.
@@ -395,7 +396,7 @@ export class Hub implements HubInterface {
     const scope = layer && layer.scope;
     const session = scope && scope.getSession();
     if (session) {
-      session.close();
+      closeSession(session);
     }
     this._sendSessionUpdate();
 
@@ -416,7 +417,7 @@ export class Hub implements HubInterface {
     const global = getGlobalObject<{ navigator?: { userAgent?: string } }>();
     const { userAgent } = global.navigator || {};
 
-    const session = new Session({
+    const session = makeSession({
       release,
       environment,
       ...(scope && { user: scope.getUser() }),
@@ -428,7 +429,7 @@ export class Hub implements HubInterface {
       // End existing session if there's one
       const currentSession = scope.getSession && scope.getSession();
       if (currentSession && currentSession.status === 'ok') {
-        currentSession.update({ status: 'exited' });
+        updateSession(currentSession, { status: 'exited' });
       }
       this.endSession();
 
@@ -446,7 +447,7 @@ export class Hub implements HubInterface {
     const { scope, client } = this.getStackTop();
     if (!scope) return;
 
-    const session = scope.getSession && scope.getSession();
+    const session = scope.getSession();
     if (session) {
       if (client && client.captureSession) {
         client.captureSession(session);
diff --git a/packages/hub/src/index.ts b/packages/hub/src/index.ts
index 92b85f370d80..16c4f3680dd8 100644
--- a/packages/hub/src/index.ts
+++ b/packages/hub/src/index.ts
@@ -1,7 +1,7 @@
 export type { Carrier, Layer } from './hub';
 
 export { addGlobalEventProcessor, Scope } from './scope';
-export { Session } from './session';
+export { closeSession, makeSession, updateSession } from './session';
 export { SessionFlusher } from './sessionflusher';
 export { getCurrentHub, getHubFromCarrier, getMainCarrier, Hub, makeMain, setHubOnCarrier } from './hub';
 export {
diff --git a/packages/hub/src/scope.ts b/packages/hub/src/scope.ts
index 271827519792..b51c620d86b0 100644
--- a/packages/hub/src/scope.ts
+++ b/packages/hub/src/scope.ts
@@ -13,6 +13,7 @@ import {
   RequestSession,
   Scope as ScopeInterface,
   ScopeContext,
+  Session,
   Severity,
   SeverityLevel,
   Span,
@@ -29,7 +30,7 @@ import {
 } from '@sentry/utils';
 
 import { IS_DEBUG_BUILD } from './flags';
-import { Session } from './session';
+import { updateSession } from './session';
 
 /**
  * Absolute maximum number of breadcrumbs added to an event.
@@ -136,7 +137,7 @@ export class Scope implements ScopeInterface {
   public setUser(user: User | null): this {
     this._user = user || {};
     if (this._session) {
-      this._session.update({ user });
+      updateSession(this._session, { user });
     }
     this._notifyScopeListeners();
     return this;
diff --git a/packages/hub/src/session.ts b/packages/hub/src/session.ts
index 3206ef9306dc..fed5cfa004ad 100644
--- a/packages/hub/src/session.ts
+++ b/packages/hub/src/session.ts
@@ -1,136 +1,154 @@
-import { Session as SessionInterface, SessionContext, SessionStatus } from '@sentry/types';
+import { Session, SessionContext, SessionStatus } from '@sentry/types';
+import { SerializedSession } from '@sentry/types/build/types/session';
 import { dropUndefinedKeys, timestampInSeconds, uuid4 } from '@sentry/utils';
 
 /**
- * @inheritdoc
+ * Creates a new `Session` object by setting certain default parameters. If optional @param context
+ * is passed, the passed properties are applied to the session object.
+ *
+ * @param context (optional) additional properties to be applied to the returned session object
+ *
+ * @returns a new `Session` object
  */
-export class Session implements SessionInterface {
-  public userAgent?: string;
-  public errors: number = 0;
-  public release?: string;
-  public sid: string = uuid4();
-  public did?: string;
-  public timestamp: number;
-  public started: number;
-  public duration?: number = 0;
-  public status: SessionStatus = 'ok';
-  public environment?: string;
-  public ipAddress?: string;
-  public init: boolean = true;
-  public ignoreDuration: boolean = false;
+export function makeSession(context?: Omit<SessionContext, 'started' | 'status'>): Session {
+  // Both timestamp and started are in seconds since the UNIX epoch.
+  const startingTime = timestampInSeconds();
 
-  public constructor(context?: Omit<SessionContext, 'started' | 'status'>) {
-    // Both timestamp and started are in seconds since the UNIX epoch.
-    const startingTime = timestampInSeconds();
-    this.timestamp = startingTime;
-    this.started = startingTime;
-    if (context) {
-      this.update(context);
-    }
+  const session: Session = {
+    sid: uuid4(),
+    init: true,
+    timestamp: startingTime,
+    started: startingTime,
+    duration: 0,
+    status: 'ok',
+    errors: 0,
+    ignoreDuration: false,
+    toJSON: () => sessionToJSON(session),
+  };
+
+  if (context) {
+    updateSession(session, context);
   }
 
-  /** JSDoc */
-  // eslint-disable-next-line complexity
-  public update(context: SessionContext = {}): void {
-    if (context.user) {
-      if (!this.ipAddress && context.user.ip_address) {
-        this.ipAddress = context.user.ip_address;
-      }
+  return session;
+}
 
-      if (!this.did && !context.did) {
-        this.did = context.user.id || context.user.email || context.user.username;
-      }
+/**
+ * Updates a session object with the properties passed in the context.
+ *
+ * Note that this function mutates the passed object and returns void.
+ * (Had to do this instead of returning a new and updated session because closing and sending a session
+ * makes an update to the session after it was passed to the sending logic.
+ * @see BaseClient.captureSession )
+ *
+ * @param session the `Session` to update
+ * @param context the `SessionContext` holding the properties that should be updated in @param session
+ */
+// eslint-disable-next-line complexity
+export function updateSession(session: Session, context: SessionContext = {}): void {
+  if (context.user) {
+    if (!session.ipAddress && context.user.ip_address) {
+      session.ipAddress = context.user.ip_address;
     }
 
-    this.timestamp = context.timestamp || timestampInSeconds();
-    if (context.ignoreDuration) {
-      this.ignoreDuration = context.ignoreDuration;
-    }
-    if (context.sid) {
-      // Good enough uuid validation. — Kamil
-      this.sid = context.sid.length === 32 ? context.sid : uuid4();
-    }
-    if (context.init !== undefined) {
-      this.init = context.init;
-    }
-    if (!this.did && context.did) {
-      this.did = `${context.did}`;
-    }
-    if (typeof context.started === 'number') {
-      this.started = context.started;
-    }
-    if (this.ignoreDuration) {
-      this.duration = undefined;
-    } else if (typeof context.duration === 'number') {
-      this.duration = context.duration;
-    } else {
-      const duration = this.timestamp - this.started;
-      this.duration = duration >= 0 ? duration : 0;
-    }
-    if (context.release) {
-      this.release = context.release;
-    }
-    if (context.environment) {
-      this.environment = context.environment;
-    }
-    if (!this.ipAddress && context.ipAddress) {
-      this.ipAddress = context.ipAddress;
-    }
-    if (!this.userAgent && context.userAgent) {
-      this.userAgent = context.userAgent;
-    }
-    if (typeof context.errors === 'number') {
-      this.errors = context.errors;
-    }
-    if (context.status) {
-      this.status = context.status;
+    if (!session.did && !context.did) {
+      session.did = context.user.id || context.user.email || context.user.username;
     }
   }
 
-  /** JSDoc */
-  public close(status?: Exclude<SessionStatus, 'ok'>): void {
-    if (status) {
-      this.update({ status });
-    } else if (this.status === 'ok') {
-      this.update({ status: 'exited' });
-    } else {
-      this.update();
-    }
+  session.timestamp = context.timestamp || timestampInSeconds();
+
+  if (context.ignoreDuration) {
+    session.ignoreDuration = context.ignoreDuration;
+  }
+  if (context.sid) {
+    // Good enough uuid validation. — Kamil
+    session.sid = context.sid.length === 32 ? context.sid : uuid4();
   }
+  if (context.init !== undefined) {
+    session.init = context.init;
+  }
+  if (!session.did && context.did) {
+    session.did = `${context.did}`;
+  }
+  if (typeof context.started === 'number') {
+    session.started = context.started;
+  }
+  if (session.ignoreDuration) {
+    session.duration = undefined;
+  } else if (typeof context.duration === 'number') {
+    session.duration = context.duration;
+  } else {
+    const duration = session.timestamp - session.started;
+    session.duration = duration >= 0 ? duration : 0;
+  }
+  if (context.release) {
+    session.release = context.release;
+  }
+  if (context.environment) {
+    session.environment = context.environment;
+  }
+  if (!session.ipAddress && context.ipAddress) {
+    session.ipAddress = context.ipAddress;
+  }
+  if (!session.userAgent && context.userAgent) {
+    session.userAgent = context.userAgent;
+  }
+  if (typeof context.errors === 'number') {
+    session.errors = context.errors;
+  }
+  if (context.status) {
+    session.status = context.status;
+  }
+}
 
-  /** JSDoc */
-  public toJSON(): {
-    init: boolean;
-    sid: string;
-    did?: string;
-    timestamp: string;
-    started: string;
-    duration?: number;
-    status: SessionStatus;
-    errors: number;
-    attrs?: {
-      release?: string;
-      environment?: string;
-      user_agent?: string;
-      ip_address?: string;
-    };
-  } {
-    return dropUndefinedKeys({
-      sid: `${this.sid}`,
-      init: this.init,
-      // Make sure that sec is converted to ms for date constructor
-      started: new Date(this.started * 1000).toISOString(),
-      timestamp: new Date(this.timestamp * 1000).toISOString(),
-      status: this.status,
-      errors: this.errors,
-      did: typeof this.did === 'number' || typeof this.did === 'string' ? `${this.did}` : undefined,
-      duration: this.duration,
-      attrs: {
-        release: this.release,
-        environment: this.environment,
-        ip_address: this.ipAddress,
-        user_agent: this.userAgent,
-      },
-    });
+/**
+ * Closes a session by setting its status and updating the session object with it.
+ * Internally calls `updateSession` to update the passed session object.
+ *
+ * Note that this function mutates the passed session (@see updateSession for explanation).
+ *
+ * @param session the `Session` object to be closed
+ * @param status the `SessionStatus` with which the session was closed. If you don't pass a status,
+ *               this function will keep the previously set status, unless it was `'ok'` in which case
+ *               it is changed to `'exited'`.
+ */
+export function closeSession(session: Session, status?: Exclude<SessionStatus, 'ok'>): void {
+  let context = {};
+  if (status) {
+    context = { status };
+  } else if (session.status === 'ok') {
+    context = { status: 'exited' };
   }
+
+  updateSession(session, context);
+}
+
+/**
+ * Serializes a passed session object to a JSON object with a slightly different structure.
+ * This is necessary because the Sentry backend requires a slightly different schema of a session
+ * than the one the JS SDKs use internally.
+ *
+ * @param session the session to be converted
+ *
+ * @returns a JSON object of the passed session
+ */
+function sessionToJSON(session: Session): SerializedSession {
+  return dropUndefinedKeys({
+    sid: `${session.sid}`,
+    init: session.init,
+    // Make sure that sec is converted to ms for date constructor
+    started: new Date(session.started * 1000).toISOString(),
+    timestamp: new Date(session.timestamp * 1000).toISOString(),
+    status: session.status,
+    errors: session.errors,
+    did: typeof session.did === 'number' || typeof session.did === 'string' ? `${session.did}` : undefined,
+    duration: session.duration,
+    attrs: {
+      release: session.release,
+      environment: session.environment,
+      ip_address: session.ipAddress,
+      user_agent: session.userAgent,
+    },
+  });
 }
diff --git a/packages/hub/test/session.test.ts b/packages/hub/test/session.test.ts
index f25e5ad4189b..f57267fd11c0 100644
--- a/packages/hub/test/session.test.ts
+++ b/packages/hub/test/session.test.ts
@@ -1,11 +1,12 @@
 import { SessionContext } from '@sentry/types';
 import { timestampInSeconds } from '@sentry/utils';
 
-import { Session } from '../src/session';
+import { closeSession, makeSession, updateSession } from '../src/session';
 
 describe('Session', () => {
   it('initializes with the proper defaults', () => {
-    const session = new Session().toJSON();
+    const newSession = makeSession();
+    const session = newSession.toJSON();
 
     // Grab current year to check if we are converting from sec -> ms correctly
     const currentYear = new Date(timestampInSeconds() * 1000).toISOString().slice(0, 4);
@@ -82,36 +83,39 @@ describe('Session', () => {
       // the out variable in a test explicitly refers to it.
       const DEFAULT_OUT = { duration: expect.any(Number), timestamp: expect.any(String) };
 
-      const session = new Session();
+      const session = makeSession();
       const initSessionProps = session.toJSON();
 
-      session.update(test[1]);
-      expect(session.toJSON()).toEqual({ ...initSessionProps, ...DEFAULT_OUT, ...test[2] });
+      updateSession(session, test[1]);
+      const updatedSessionProps = session.toJSON();
+
+      expect(updatedSessionProps).toEqual({ ...initSessionProps, ...DEFAULT_OUT, ...test[2] });
     });
   });
 
   describe('close', () => {
     it('exits a normal session', () => {
-      const session = new Session();
+      const session = makeSession();
       expect(session.status).toEqual('ok');
-      session.close();
+
+      closeSession(session);
       expect(session.status).toEqual('exited');
     });
 
     it('updates session status when give status', () => {
-      const session = new Session();
+      const session = makeSession();
       expect(session.status).toEqual('ok');
 
-      session.close('abnormal');
+      closeSession(session, 'abnormal');
       expect(session.status).toEqual('abnormal');
     });
 
     it('only changes status ok to exited', () => {
-      const session = new Session();
-      session.update({ status: 'crashed' });
+      const session = makeSession();
+      updateSession(session, { status: 'crashed' });
       expect(session.status).toEqual('crashed');
 
-      session.close();
+      closeSession(session, 'crashed');
       expect(session.status).toEqual('crashed');
     });
   });
diff --git a/packages/node/src/index.ts b/packages/node/src/index.ts
index 823dc73d848e..cea9a4554ccb 100644
--- a/packages/node/src/index.ts
+++ b/packages/node/src/index.ts
@@ -6,6 +6,7 @@ export type {
   Event,
   EventHint,
   Exception,
+  Session,
   // eslint-disable-next-line deprecation/deprecation
   Severity,
   SeverityLevel,
@@ -30,7 +31,6 @@ export {
   Hub,
   makeMain,
   Scope,
-  Session,
   startTransaction,
   SDK_VERSION,
   setContext,
diff --git a/packages/types/src/hub.ts b/packages/types/src/hub.ts
index 9a67968a4fc1..a34d4372e08d 100644
--- a/packages/types/src/hub.ts
+++ b/packages/types/src/hub.ts
@@ -5,7 +5,7 @@ import { Extra, Extras } from './extra';
 import { Integration, IntegrationClass } from './integration';
 import { Primitive } from './misc';
 import { Scope } from './scope';
-import { Session, SessionContext } from './session';
+import { Session } from './session';
 import { Severity, SeverityLevel } from './severity';
 import { CustomSamplingContext, Transaction, TransactionContext } from './transaction';
 import { User } from './user';
@@ -215,7 +215,7 @@ export interface Hub {
    *
    * @returns The session which was just started
    */
-  startSession(context?: SessionContext): Session;
+  startSession(context?: Session): Session;
 
   /**
    * Ends the session that lives on the current scope and sends it to Sentry
diff --git a/packages/types/src/session.ts b/packages/types/src/session.ts
index 237e4c41808d..35d5e0840a3e 100644
--- a/packages/types/src/session.ts
+++ b/packages/types/src/session.ts
@@ -1,60 +1,39 @@
 import { User } from './user';
 
-/**
- * @inheritdoc
- */
-export interface Session extends SessionContext {
-  /** JSDoc */
-  update(context?: SessionContext): void;
-
-  /** JSDoc */
-  close(status?: SessionStatus): void;
-
-  /** JSDoc */
-  toJSON(): {
-    init: boolean;
-    sid: string;
-    did?: string;
-    timestamp: string;
-    started: string;
-    duration?: number;
-    status: SessionStatus;
-    errors: number;
-    attrs?: {
-      release?: string;
-      environment?: string;
-      user_agent?: string;
-      ip_address?: string;
-    };
-  };
-}
-
 export interface RequestSession {
   status?: RequestSessionStatus;
 }
 
-/**
- * Session Context
- */
-export interface SessionContext {
-  sid?: string;
+export interface Session {
+  sid: string;
   did?: string;
-  init?: boolean;
+  init: boolean;
   // seconds since the UNIX epoch
-  timestamp?: number;
+  timestamp: number;
   // seconds since the UNIX epoch
-  started?: number;
+  started: number;
   duration?: number;
-  status?: SessionStatus;
+  status: SessionStatus;
   release?: string;
   environment?: string;
   userAgent?: string;
   ipAddress?: string;
-  errors?: number;
+  errors: number;
   user?: User | null;
-  ignoreDuration?: boolean;
+  ignoreDuration: boolean;
+
+  /**
+   * Overrides default JSON serialization of the Session because
+   * the Sentry servers expect a slightly different schema of a session
+   * which is described in the interface @see SerializedSession in this file.
+   *
+   * @return a Sentry-backend conforming JSON object of the session
+   */
+  toJSON(): SerializedSession;
 }
 
+export type SessionContext = Partial<Session>;
+
 export type SessionStatus = 'ok' | 'exited' | 'crashed' | 'abnormal';
 export type RequestSessionStatus = 'ok' | 'errored' | 'crashed';
 
@@ -87,3 +66,20 @@ export interface AggregationCounts {
   exited?: number;
   crashed?: number;
 }
+
+export interface SerializedSession {
+  init: boolean;
+  sid: string;
+  did?: string;
+  timestamp: string;
+  started: string;
+  duration?: number;
+  status: SessionStatus;
+  errors: number;
+  attrs?: {
+    release?: string;
+    environment?: string;
+    user_agent?: string;
+    ip_address?: string;
+  };
+}