diff --git a/packages/nostr/package.json b/packages/nostr/package.json
index b291a25..caf7b6e 100644
--- a/packages/nostr/package.json
+++ b/packages/nostr/package.json
@@ -9,5 +9,8 @@
   },
   "devDependencies": {
     "typescript": "^4.9.5"
+  },
+  "prettier": {
+    "semi": false
   }
 }
diff --git a/packages/nostr/src/error.ts b/packages/nostr/src/error.ts
new file mode 100644
index 0000000..4869911
--- /dev/null
+++ b/packages/nostr/src/error.ts
@@ -0,0 +1,9 @@
+/**
+ * An error in the protocol. This error is thrown when a relay sends invalid or
+ * unexpected data, or otherwise behaves in an unexpected way.
+ */
+export class ProtocolError extends Error {
+  constructor(message?: string) {
+    super(message)
+  }
+}
diff --git a/packages/nostr/src/event.ts b/packages/nostr/src/event.ts
new file mode 100644
index 0000000..9636844
--- /dev/null
+++ b/packages/nostr/src/event.ts
@@ -0,0 +1,174 @@
+import { ProtocolError } from "./error"
+import { RawEvent } from "./raw"
+import * as secp from "@noble/secp256k1"
+import { PublicKey } from "./keypair"
+import { parseHex } from "./util"
+
+// TODO This file is missing proper documentation
+// TODO Add remaining event types
+
+export enum EventKind {
+  SetMetadata = 0, // NIP-01
+  TextNote = 1, // NIP-01
+  RecommendServer = 2, // NIP-01
+  ContactList = 3, // NIP-02
+  DirectMessage = 4, // NIP-04
+  Deletion = 5, // NIP-09
+  Repost = 6, // NIP-18
+  Reaction = 7, // NIP-25
+  Relays = 10002, // NIP-65
+  Auth = 22242, // NIP-42
+  PubkeyLists = 30000, // NIP-51a
+  NoteLists = 30001, // NIP-51b
+  TagLists = 30002, // NIP-51c
+  ZapRequest = 9734, // NIP 57
+  ZapReceipt = 9735, // NIP 57
+}
+
+export type Event = SetMetadataEvent | TextNoteEvent | UnknownEvent
+
+interface EventCommon {
+  pubkey: PublicKey
+  createdAt: Date
+}
+
+export interface SetMetadataEvent extends EventCommon {
+  kind: EventKind.SetMetadata
+  userMetadata: UserMetadata
+}
+
+export interface UserMetadata {
+  name: string
+  about: string
+  picture: string
+}
+
+export interface TextNoteEvent extends EventCommon {
+  kind: EventKind.TextNote
+  note: string
+}
+
+export interface UnknownEvent extends EventCommon {
+  kind: Exclude<EventKind, EventKind.SetMetadata | EventKind.TextNote>
+}
+
+export async function createEvent(raw: RawEvent): Promise<Event> {
+  const pubkey = new PublicKey(raw.pubkey)
+  const createdAt = new Date(raw.created_at * 1000)
+  const event = {
+    pubkey,
+    createdAt,
+  }
+  await checkSignature(raw, event)
+  return (
+    createSetMetadataEvent(raw, event) ??
+    createTextNodeEvent(raw, event) ??
+    createUnknownEvent(raw, event)
+  )
+}
+
+function createSetMetadataEvent(
+  raw: RawEvent,
+  event: EventCommon
+): SetMetadataEvent | undefined {
+  if (raw.kind !== EventKind.SetMetadata) {
+    return undefined
+  }
+  const userMetadata = parseJson(raw.content)
+  if (
+    typeof userMetadata["name"] !== "string" ||
+    typeof userMetadata["about"] !== "string" ||
+    typeof userMetadata["picture"] !== "string"
+  ) {
+    throw new ProtocolError(`invalid user metadata: ${userMetadata}`)
+  }
+  return {
+    ...event,
+    kind: EventKind.SetMetadata,
+    userMetadata,
+  }
+}
+
+function createTextNodeEvent(
+  raw: RawEvent,
+  event: EventCommon
+): TextNoteEvent | undefined {
+  if (raw.kind !== EventKind.TextNote) {
+    return undefined
+  }
+  return {
+    ...event,
+    kind: EventKind.TextNote,
+    note: raw.content,
+  }
+}
+
+function createUnknownEvent(raw: RawEvent, event: EventCommon): UnknownEvent {
+  return {
+    ...event,
+    kind: raw.kind,
+  }
+}
+
+export class EventId {
+  #hex: string
+
+  constructor(hex: string | Uint8Array) {
+    this.#hex = parseHex(hex)
+    if (this.#hex.length !== 128) {
+      throw new ProtocolError(`invalid event id: ${this.#hex}`)
+    }
+  }
+
+  toString(): string {
+    return this.#hex
+  }
+}
+
+async function checkSignature(
+  raw: RawEvent,
+  event: EventCommon
+): Promise<void> {
+  const id = serializeId(raw)
+  const bytes = await secp.schnorr.sign(id.toString(), event.pubkey.toString())
+  const hex = secp.utils.bytesToHex(bytes).toLowerCase()
+  if (hex.toString() !== raw.sig) {
+    throw new ProtocolError("invalid signature: ${hex}")
+  }
+}
+
+async function serializeId(raw: RawEvent): Promise<EventId> {
+  // It's not defined whether JSON.stringify produces a string with whitespace stripped.
+  // Building the JSON string manually this way ensures that there's no whitespace.
+  // In hindsight using JSON as a data format for hashing and signing is not the best
+  // design decision.
+  const serializedTags = `[${raw.tags
+    .map((tag) => `[${tag.map((v) => `"${v}"`).join(",")}]`)
+    .join(",")}]`
+  const serialized = `[0,"${raw.pubkey}",${raw.created_at},${raw.kind},${serializedTags},"${raw.content}"]`
+  const hash = await secp.utils.sha256(Uint8Array.from(charCodes(serialized)))
+  return new EventId(secp.utils.bytesToHex(hash).toLowerCase())
+}
+
+function parseJson(data: string) {
+  try {
+    return JSON.parse(data)
+  } catch (e) {
+    throw new ProtocolError(`invalid json: ${data}`)
+  }
+}
+
+function* charCodes(data: string): Iterable<number> {
+  for (let i = 0; i < length; i++) {
+    yield data.charCodeAt(i)
+  }
+}
+
+// TODO This is an example of how this API can be used, remove this later
+function isItNice(e: Event): void {
+  if (e.kind === EventKind.SetMetadata) {
+    console.log(e.userMetadata)
+  } else if (e.kind === EventKind.TextNote) {
+    console.log(e.note)
+  }
+}
diff --git a/packages/nostr/src/index.ts b/packages/nostr/src/index.ts
index a3ae6c9..c74de3f 100644
--- a/packages/nostr/src/index.ts
+++ b/packages/nostr/src/index.ts
@@ -1,87 +1,3 @@
-export * from "./System";
-export * from "./Connection";
-export { default as EventKind } from "./EventKind";
-export { Subscriptions } from "./Subscriptions";
-export { default as Event } from "./Event";
-export { default as Tag } from "./Tag";
-export * from "./Links";
+export * from "./legacy"
 
-export type RawEvent = {
-  id: u256;
-  pubkey: HexKey;
-  created_at: number;
-  kind: number;
-  tags: string[][];
-  content: string;
-  sig: string;
-};
-
-export interface TaggedRawEvent extends RawEvent {
-  /**
-   * A list of relays this event was seen on
-   */
-  relays: string[];
-}
-
-/**
- * Basic raw key as hex
- */
-export type HexKey = string;
-
-/**
- * Optional HexKey
- */
-export type MaybeHexKey = HexKey | undefined;
-
-/**
- * A 256bit hex id
- */
-export type u256 = string;
-
-/**
- * Raw REQ filter object
- */
-export type RawReqFilter = {
-  ids?: u256[];
-  authors?: u256[];
-  kinds?: number[];
-  "#e"?: u256[];
-  "#p"?: u256[];
-  "#t"?: string[];
-  "#d"?: string[];
-  "#r"?: string[];
-  search?: string;
-  since?: number;
-  until?: number;
-  limit?: number;
-};
-
-/**
- * Medatadata event content
- */
-export type UserMetadata = {
-  name?: string;
-  display_name?: string;
-  about?: string;
-  picture?: string;
-  website?: string;
-  banner?: string;
-  nip05?: string;
-  lud06?: string;
-  lud16?: string;
-};
-
-/**
- * NIP-51 list types
- */
-export enum Lists {
-  Muted = "mute",
-  Pinned = "pin",
-  Bookmarked = "bookmark",
-  Followed = "follow",
-}
-
-export interface FullRelaySettings {
-  url: string;
-  settings: { read: boolean; write: boolean };
-}
+// TODO This file should only contain re-exports and only re-export what is needed
diff --git a/packages/nostr/src/keypair.ts b/packages/nostr/src/keypair.ts
new file mode 100644
index 0000000..0a77d1c
--- /dev/null
+++ b/packages/nostr/src/keypair.ts
@@ -0,0 +1,38 @@
+import { ProtocolError } from "./error"
+import { parseHex } from "./util"
+
+/**
+ * A 32-byte secp256k1 public key.
+ */
+export class PublicKey {
+  #hex: string
+
+  constructor(hex: string | Uint8Array) {
+    this.#hex = parseHex(hex)
+    if (this.#hex.length !== 64) {
+      throw new ProtocolError(`invalid pubkey: ${hex}`)
+    }
+  }
+
+  toString(): string {
+    return this.#hex
+  }
+}
+
+/**
+ * A 32-byte secp256k1 private key.
+ */
+export class PrivateKey {
+  #hex: string
+
+  constructor(hex: string | Uint8Array) {
+    this.#hex = parseHex(hex)
+    if (this.#hex.length !== 64) {
+      throw new ProtocolError(`invalid private key: ${this.#hex}`)
+    }
+  }
+
+  toString(): string {
+    return this.#hex
+  }
+}
diff --git a/packages/nostr/src/legacy/.prettierrc b/packages/nostr/src/legacy/.prettierrc
new file mode 100644
index 0000000..0967ef4
--- /dev/null
+++ b/packages/nostr/src/legacy/.prettierrc
@@ -0,0 +1 @@
+{}
diff --git a/packages/nostr/src/Connection.ts b/packages/nostr/src/legacy/Connection.ts
similarity index 100%
rename from packages/nostr/src/Connection.ts
rename to packages/nostr/src/legacy/Connection.ts
diff --git a/packages/nostr/src/ConnectionStats.ts b/packages/nostr/src/legacy/ConnectionStats.ts
similarity index 100%
rename from packages/nostr/src/ConnectionStats.ts
rename to packages/nostr/src/legacy/ConnectionStats.ts
diff --git a/packages/nostr/src/Const.ts b/packages/nostr/src/legacy/Const.ts
similarity index 100%
rename from packages/nostr/src/Const.ts
rename to packages/nostr/src/legacy/Const.ts
diff --git a/packages/nostr/src/Event.ts b/packages/nostr/src/legacy/Event.ts
similarity index 100%
rename from packages/nostr/src/Event.ts
rename to packages/nostr/src/legacy/Event.ts
diff --git a/packages/nostr/src/EventKind.ts b/packages/nostr/src/legacy/EventKind.ts
similarity index 100%
rename from packages/nostr/src/EventKind.ts
rename to packages/nostr/src/legacy/EventKind.ts
diff --git a/packages/nostr/src/Links.ts b/packages/nostr/src/legacy/Links.ts
similarity index 100%
rename from packages/nostr/src/Links.ts
rename to packages/nostr/src/legacy/Links.ts
diff --git a/packages/nostr/src/Nips.ts b/packages/nostr/src/legacy/Nips.ts
similarity index 100%
rename from packages/nostr/src/Nips.ts
rename to packages/nostr/src/legacy/Nips.ts
diff --git a/packages/nostr/src/RelayInfo.ts b/packages/nostr/src/legacy/RelayInfo.ts
similarity index 100%
rename from packages/nostr/src/RelayInfo.ts
rename to packages/nostr/src/legacy/RelayInfo.ts
diff --git a/packages/nostr/src/Subscriptions.ts b/packages/nostr/src/legacy/Subscriptions.ts
similarity index 100%
rename from packages/nostr/src/Subscriptions.ts
rename to packages/nostr/src/legacy/Subscriptions.ts
diff --git a/packages/nostr/src/System.ts b/packages/nostr/src/legacy/System.ts
similarity index 100%
rename from packages/nostr/src/System.ts
rename to packages/nostr/src/legacy/System.ts
diff --git a/packages/nostr/src/Tag.ts b/packages/nostr/src/legacy/Tag.ts
similarity index 100%
rename from packages/nostr/src/Tag.ts
rename to packages/nostr/src/legacy/Tag.ts
diff --git a/packages/nostr/src/Thread.ts b/packages/nostr/src/legacy/Thread.ts
similarity index 100%
rename from packages/nostr/src/Thread.ts
rename to packages/nostr/src/legacy/Thread.ts
diff --git a/packages/nostr/src/Util.ts b/packages/nostr/src/legacy/Util.ts
similarity index 100%
rename from packages/nostr/src/Util.ts
rename to packages/nostr/src/legacy/Util.ts
diff --git a/packages/nostr/src/legacy/index.ts b/packages/nostr/src/legacy/index.ts
new file mode 100644
index 0000000..a3ae6c9
--- /dev/null
+++ b/packages/nostr/src/legacy/index.ts
@@ -0,0 +1,87 @@
+export * from "./System";
+export * from "./Connection";
+export { default as EventKind } from "./EventKind";
+export { Subscriptions } from "./Subscriptions";
+export { default as Event } from "./Event";
+export { default as Tag } from "./Tag";
+export * from "./Links";
+
+export type RawEvent = {
+  id: u256;
+  pubkey: HexKey;
+  created_at: number;
+  kind: number;
+  tags: string[][];
+  content: string;
+  sig: string;
+};
+
+export interface TaggedRawEvent extends RawEvent {
+  /**
+   * A list of relays this event was seen on
+   */
+  relays: string[];
+}
+
+/**
+ * Basic raw key as hex
+ */
+export type HexKey = string;
+
+/**
+ * Optional HexKey
+ */
+export type MaybeHexKey = HexKey | undefined;
+
+/**
+ * A 256bit hex id
+ */
+export type u256 = string;
+
+/**
+ * Raw REQ filter object
+ */
+export type RawReqFilter = {
+  ids?: u256[];
+  authors?: u256[];
+  kinds?: number[];
+  "#e"?: u256[];
+  "#p"?: u256[];
+  "#t"?: string[];
+  "#d"?: string[];
+  "#r"?: string[];
+  search?: string;
+  since?: number;
+  until?: number;
+  limit?: number;
+};
+
+/**
+ * Medatadata event content
+ */
+export type UserMetadata = {
+  name?: string;
+  display_name?: string;
+  about?: string;
+  picture?: string;
+  website?: string;
+  banner?: string;
+  nip05?: string;
+  lud06?: string;
+  lud16?: string;
+};
+
+/**
+ * NIP-51 list types
+ */
+export enum Lists {
+  Muted = "mute",
+  Pinned = "pin",
+  Bookmarked = "bookmark",
+  Followed = "follow",
+}
+
+export interface FullRelaySettings {
+  url: string;
+  settings: { read: boolean; write: boolean };
+}
diff --git a/packages/nostr/src/nostr.ts b/packages/nostr/src/nostr.ts
new file mode 100644
index 0000000..0a9d814
--- /dev/null
+++ b/packages/nostr/src/nostr.ts
@@ -0,0 +1,134 @@
+import { ProtocolError } from "./error"
+import { EventId, Event } from "./event"
+import { RawEvent } from "./raw"
+
+/**
+ * A nostr client.
+ */
+export class Nostr {
+  /**
+   * Open connections to relays.
+   */
+  #conns: Conn[] = []
+  /**
+   * Is this client closed?
+   */
+  #closed: boolean = false
+  /**
+   * Mapping of subscription IDs to corresponding filters.
+   */
+  #subscriptions: Map<string, Filters> = new Map()
+
+  #eventCallbacks: EventCallback[] = []
+  #noticeCallbacks: NoticeCallback[] = []
+  #errorCallbacks: ErrorCallback[] = []
+
+  /**
+   * Add a new callback for received events.
+   */
+  onEvent(cb: EventCallback): void {
+    this.#eventCallbacks.push(cb)
+  }
+
+  /**
+   * Add a new callback for received notices.
+   */
+  onNotice(cb: NoticeCallback): void {
+    this.#noticeCallbacks.push(cb)
+  }
+
+  /**
+   * Add a new callback for errors.
+   */
+  onError(cb: ErrorCallback): void {
+    this.#errorCallbacks.push(cb)
+  }
+
+  /**
+   * Connect and start communicating with a relay. This method recreates all existing
+   * subscriptions on the new relay as well.
+   */
+  async connect(relay: URL | string): Promise<void> {
+    this.#checkClosed()
+    throw new Error("todo try to connect and send subscriptions")
+  }
+
+  /**
+   * Create a new subscription.
+   *
+   * @param subscriptionId An optional subscription ID, otherwise a random subscription ID will be used.
+   * @returns The subscription ID.
+   */
+  async subscribe(
+    filters: Filters,
+    subscriptionId?: SubscriptionId | string
+  ): Promise<SubscriptionId> {
+    this.#checkClosed()
+    throw new Error("todo subscribe to the relays and add the subscription")
+  }
+
+  /**
+   * Remove a subscription.
+   */
+  async unsubscribe(subscriptionId: SubscriptionId): Promise<SubscriptionId> {
+    this.#checkClosed()
+    throw new Error(
+      "todo unsubscribe from the relays and remove the subscription"
+    )
+  }
+
+  /**
+   * Publish an event.
+   */
+  async publish(event: Event): Promise<void> {
+    this.#checkClosed()
+    throw new Error("todo")
+  }
+
+  /**
+   * Close connections to all relays. This method can only be called once. After the
+   * connections have been closed, no other methods can be called.
+   */
+  async close(): Promise<void> {}
+
+  #checkClosed() {
+    if (this.#closed) {
+      throw new Error("the client has been closed")
+    }
+  }
+}
+
+/**
+ * A string uniquely identifying a client subscription.
+ */
+export class SubscriptionId {
+  #id: string
+
+  constructor(subscriptionId: string) {
+    this.#id = subscriptionId
+  }
+
+  toString() {
+    return this.#id
+  }
+}
+
+/**
+ * Subscription filters.
+ */
+export interface Filters {}
+
+export type EventCallback = (params: EventParams, nostr: Nostr) => unknown
+export type NoticeCallback = (notice: string, nostr: Nostr) => unknown
+export type ErrorCallback = (error: ProtocolError, nostr: Nostr) => unknown
+
+export interface EventParams {
+  event: Event
+  id: EventId
+  raw: RawEvent
+}
+
+/**
+ * The connection to a relay.
+ */
+class Conn {}
diff --git a/packages/nostr/src/raw.ts b/packages/nostr/src/raw.ts
new file mode 100644
index 0000000..66df762
--- /dev/null
+++ b/packages/nostr/src/raw.ts
@@ -0,0 +1,41 @@
+import { ProtocolError } from "./error"
+
+/**
+ * Raw event to be transferred over the wire.
+ */
+export interface RawEvent {
+  id: string
+  pubkey: string
+  created_at: number
+  kind: number
+  tags: string[][]
+  content: string
+  sig: string
+}
+
+export function parseRawEvent(data: string): RawEvent {
+  const json = parseJson(data)
+  if (
+    typeof json["id"] !== "string" ||
+    typeof json["pubkey"] !== "string" ||
+    typeof json["created_at"] !== "number" ||
+    typeof json["kind"] !== "number" ||
+    !(json["tags"] instanceof Array) ||
+    !json["tags"].every(
+      (x) => x instanceof Array && x.every((y) => typeof y === "string")
+    ) ||
+    typeof json["content"] !== "string" ||
+    typeof json["sig"] !== "string"
+  ) {
+    throw new ProtocolError(`invalid event: ${data}`)
+  }
+  return json
+}
+
+function parseJson(data: string) {
+  try {
+    return JSON.parse(data)
+  } catch (e) {
+    throw new ProtocolError(`invalid event json: ${data}`)
+  }
+}
diff --git a/packages/nostr/src/util.ts b/packages/nostr/src/util.ts
new file mode 100644
index 0000000..6336476
--- /dev/null
+++ b/packages/nostr/src/util.ts
@@ -0,0 +1,22 @@
+import * as secp from "@noble/secp256k1"
+import { ProtocolError } from "./error"
+
+/**
+ * Check that the input is a valid lowercase hex string.
+ */
+export function parseHex(hex: string | Uint8Array): string {
+  if (typeof hex === "string") {
+    const valid = "0123456789abcdef"
+    if (hex.length % 2 != 0) {
+      throw new ProtocolError(`invalid hex string: ${hex}`)
+    }
+    for (const c of hex) {
+      if (!valid.includes(c)) {
+        throw new ProtocolError(`invalid hex string: ${hex}`)
+      }
+    }
+    return hex
+  } else {
+    return secp.utils.bytesToHex(hex).toLowerCase()
+  }
+}