diff --git a/d2m/actions/register-user.js b/d2m/actions/register-user.js
index cc5f515..1d1eb3d 100644
--- a/d2m/actions/register-user.js
+++ b/d2m/actions/register-user.js
@@ -154,6 +154,7 @@ async function syncAllUsersInRoom(roomID) {
 	}
 }
 
+module.exports._memberToStateContent = memberToStateContent
 module.exports.ensureSim = ensureSim
 module.exports.ensureSimJoined = ensureSimJoined
 module.exports.syncUser = syncUser
diff --git a/d2m/actions/register-user.test.js b/d2m/actions/register-user.test.js
new file mode 100644
index 0000000..7e23450
--- /dev/null
+++ b/d2m/actions/register-user.test.js
@@ -0,0 +1,24 @@
+const {channelToKState} = require("./create-room")
+const {_memberToStateContent} = require("./register-user")
+const {test} = require("supertape")
+const testData = require("../../test/data")
+
+test("member2state: general", async t => {
+   t.deepEqual(
+      await _memberToStateContent(testData.member.sheep.user, testData.member.sheep, testData.guild.general.id),
+      {
+         avatar_url: "mxc://cadence.moe/rfemHmAtcprjLEiPiEuzPhpl",
+         displayname: "The Expert's Submarine | aprilsong",
+         membership: "join",
+         "moe.cadence.ooye.member": {
+            avatar: "/guilds/112760669178241024/users/134826546694193153/avatars/38dd359aa12bcd52dd3164126c587f8c.png?size=1024"
+         },
+         "uk.half-shot.discord.member": {
+            bot: false,
+            displayColor: null,
+            id: "134826546694193153",
+            username: "@aprilsong"
+         }
+      }
+   )
+})
diff --git a/db/ooye.db b/db/ooye.db
index 9c7d480..be56505 100644
Binary files a/db/ooye.db and b/db/ooye.db differ
diff --git a/m2d/actions/register-webhook.js b/m2d/actions/register-webhook.js
new file mode 100644
index 0000000..511029b
--- /dev/null
+++ b/m2d/actions/register-webhook.js
@@ -0,0 +1,50 @@
+// @ts-check
+
+const assert = require("assert").strict
+const passthrough = require("../../passthrough")
+const {discord, db} = passthrough
+
+/**
+ * Look in the database to find webhook credentials for a channel.
+ * (Note that the credentials may be invalid and need to be re-created if the webhook was interfered with from outside.)
+ * @param {string} channelID
+ * @param {boolean} forceCreate create a new webhook no matter what the database says about the state
+ * @returns id and token for a webhook for that channel
+ */
+async function ensureWebhook(channelID, forceCreate = false) {
+	if (!forceCreate) {
+		/** @type {{id: string, token: string} | null} */
+		const row = db.prepare("SELECT webhook_id as id, webhook_token as token FROM webhook WHERE channel_id = ?").get(channelID)
+		if (row) {
+			return {created: false, ...row}
+		}
+	}
+
+	// If we got here, we need to create a new webhook.
+	const webhook = await discord.snow.webhook.createWebhook(channelID, {name: "Out Of Your Element: Matrix Bridge"})
+	assert(webhook.token)
+	db.prepare("REPLACE INTO webhook (channel_id, webhook_id, webhook_token) VALUES (?, ?, ?)").run(channelID, webhook.id, webhook.token)
+	return {
+		id: webhook.id,
+		token: webhook.token,
+		created: true
+	}
+}
+
+/**
+ * @param {string} channelID
+ * @param {(webhook: import("../../types").WebhookCreds) => Promise<T>} callback
+ * @returns Promise<T>
+ * @template T
+ */
+async function withWebhook(channelID, callback) {
+	const webhook = await ensureWebhook(channelID, false)
+	return callback(webhook).catch(e => {
+		console.error(e)
+		// TODO: check if the error was webhook-related and if webhook.created === false, then: const webhook = ensureWebhook(channelID, true); return callback(webhook)
+		throw new Error(e)
+	})
+}
+
+module.exports.ensureWebhook = ensureWebhook
+module.exports.withWebhook = withWebhook
diff --git a/m2d/actions/send-message.js b/m2d/actions/send-message.js
new file mode 100644
index 0000000..9c61107
--- /dev/null
+++ b/m2d/actions/send-message.js
@@ -0,0 +1,23 @@
+// @ts-check
+
+const assert = require("assert").strict
+const DiscordTypes = require("discord-api-types/v10")
+const passthrough = require("../../passthrough")
+const {sync, discord, db} = passthrough
+
+/** @type {import("./register-webhook")} */
+const registerWebhook = sync.require("./register-webhook")
+
+/**
+ * @param {string} channelID
+ * @param {DiscordTypes.RESTPostAPIWebhookWithTokenJSONBody & {name: string, file: Buffer}[]} data
+ */
+// param {DiscordTypes.RESTPostAPIWebhookWithTokenQuery & {wait: true, disableEveryone?: boolean}} options
+async function sendMessage(channelID, data) {
+   const result = await registerWebhook.withWebhook(channelID, async webhook => {
+      return discord.snow.webhook.executeWebhook(webhook.id, webhook.token, data, {wait: true, disableEveryone: true})
+   })
+   return result
+}
+
+module.exports.sendMessage = sendMessage
diff --git a/test/data.js b/test/data.js
index bb70cbe..85b3cd4 100644
--- a/test/data.js
+++ b/test/data.js
@@ -93,6 +93,51 @@ module.exports = {
 			system_channel_flags: 0|0
 		}
 	},
+	member: {
+		sheep: {
+			avatar: "38dd359aa12bcd52dd3164126c587f8c",
+			communication_disabled_until: null,
+			flags: 0,
+			joined_at: "2020-10-14T22:08:37.804000+00:00",
+			nick: "The Expert's Submarine",
+			pending: false,
+			premium_since: "2022-05-04T00:28:44.326000+00:00",
+			roles: [
+				"112767366235959296",  "118924814567211009",
+				"118923488755974146",  "199995902742626304",
+				"204427286542417920",  "217013981053845504",
+				"222168467627835392",  "260993819204386816",
+				"265239342648131584",  "271173313575780353",
+				"225744901915148298",  "287733611912757249",
+				"318243902521868288",  "348651574924541953",
+				"352291384021090304",  "378402925128712193",
+				"392141548932038658",  "393912152173576203",
+				"1123460940935991296", "872274377150980116",
+				"373336013109461013",  "530220455085473813",
+				"768280323829137430",  "842343433452257310",
+				"454567553738473472",  "920107226528612383",
+				"1123528381514911745", "1040735082610167858",
+				"585531096071012409",  "849737964090556488",
+				"660272211449479249"
+			],
+			user: {
+				id: "134826546694193153",
+				username: "aprilsong",
+				avatar: "c754c120bce07ae3b3130e2b0e61d9dd",
+				discriminator: "0",
+				public_flags: 640,
+				flags: 640,
+				banner: "a3ad0693213f9dbf793b4159dbae0717",
+				accent_color: null,
+				global_name: "sheep",
+				avatar_decoration: null,
+				display_name: "sheep",
+				banner_color: null
+			},
+			mute: false,
+			deaf: false
+		}
+	},
 	message: {
 		// Display order is text content, attachments, then stickers
 		sticker: {
diff --git a/test/test.js b/test/test.js
index ae6aea6..5f06ae4 100644
--- a/test/test.js
+++ b/test/test.js
@@ -17,3 +17,4 @@ require("../matrix/read-registration.test")
 require("../d2m/converters/message-to-event.test")
 require("../d2m/actions/create-room.test")
 require("../d2m/converters/user-to-mxid.test")
+require("../d2m/actions/register-user.test")
diff --git a/types.d.ts b/types.d.ts
index bc24329..aaa8db1 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -9,6 +9,11 @@ export type AppServiceRegistrationConfig = {
 	rate_limited: boolean
 }
 
+export type WebhookCreds = {
+	id: string
+	token: string
+}
+
 namespace Event {
 	export type BaseStateEvent = {
 		type: string