diff --git a/controller.ts b/controller.ts
index 148a50c..008b4a0 100644
--- a/controller.ts
+++ b/controller.ts
@@ -1,117 +1,202 @@
 import type {ControllerPluginContext} from '@clusterio/controller';
+import {REST, Routes} from 'discord.js';
 import {ChatEvent} from './index.js';
-import * as Discord from 'discord.js';
 
-const MAX_DISCORD_MESSAGE_LENGTH = 1950;
+/* Controller-side half of the chat relay: Factorio chat -> Discord.
+ * One-way only, so this talks to the REST API directly instead of opening a
+ * gateway Client: no intents (and no privileged MessageContent verification),
+ * no login/destroy lifecycle, no reconnect state machine.
+*/
+
+// Discord's hard limit is 2000; keep headroom for future decoration.
+const MAX_MESSAGE_LENGTH = 1950;
+
+// Only break on a word boundary if it gets us at least this far into the window.
+const MIN_WORD_BREAK_FILL = 0.5;
+
+const ERROR_UNKNOWN_CHANNEL = 10003;
+
+interface DiscordError {
+    code?: number;
+    status?: number;
+    message?: string;
+    stack?: string;
+}
+
+const stackOf = (err: unknown): string => (err as DiscordError)?.stack ?? String(err);
+const codeOf = (err: unknown): number | undefined => (err as DiscordError)?.code;
+
+/** Split `text` into chunks of at most `limit` code points, preferring word boundaries. */
+function splitMessage(text: string, limit: number): string[] {
+    if (text.length <= limit) {
+        return text.length === 0 ? [] : [text];
+    }
+
+    // Array.from, not slice, so we never cut an emoji's surrogate pair in half.
+    const chars = Array.from(text);
+    const chunks: string[] = [];
+    let offset = 0;
+
+    while (offset < chars.length) {
+        let end = Math.min(offset + limit, chars.length);
+
+        if (end < chars.length) {
+            const window = chars.slice(offset, end);
+            let newline = -1;
+            let space = -1;
+
+            for (let i = window.length - 1; i > 0; i--) {
+                if (window[i] === '\n') {
+                    newline = i;
+                    break;
+                }
+
+                if (space === -1 && window[i] === ' ') {
+                    space = i;
+                }
+            }
+
+            const cut = newline > 0 ? newline : space;
+            if (cut >= window.length * MIN_WORD_BREAK_FILL) {
+                end = offset + cut;
+            }
+        }
+
+        chunks.push(chars.slice(offset, end).join('').trim());
+        offset = end;
+
+        // Skip the whitespace we broke on so it doesn't open the next chunk.
+        while (offset < chars.length && /\s/.test(chars[offset])) {
+            offset++;
+        }
+    }
+
+    return chunks.filter(chunk => chunk.length > 0);
+}
 
 export default async function(context: ControllerPluginContext) {
     const {controller, logger, plugin} = context;
-    let client: Discord.Client | null = null;
 
-    const clientDestroy = async () => {
-        if (client) {
-            await client.destroy();
-        }
+    let rest: REST | null = null;
+    let shuttingDown = false;
 
-        client = null;
+    // Log-once guards. A channel that is unmapped or unusable gets hit once per chat
+    // line, which is how a typo in the config turns into a 10k-line log file.
+    const warnedNoMapping = new Set<string>();
+    const warnedBadChannel = new Set<string>();
+
+    // Serialise reconnects so two quick config changes can't interleave and have
+    // the older attempt null out the newer client.
+    let chain: Promise<unknown> = Promise.resolve();
+    const enqueue = <T>(fn: () => Promise<T>): Promise<T> => {
+        const run = chain.then(fn, fn);
+        chain = run.catch(() => {});
+        return run;
     };
 
     const connect = async () => {
-        await clientDestroy();
-        const token = controller.config.get('chat_relay.discord_bot_token') as string | undefined;
+        rest = null;
 
+        const token = controller.config.get('chat_relay.discord_bot_token') as string | undefined;
         if (!token) {
             logger.error('[Chat Relay] Discord bot token not configured.');
             return;
         }
 
-        client = new Discord.Client({intents: [
-            Discord.GatewayIntentBits.Guilds,
-            Discord.GatewayIntentBits.GuildMessages,
-            Discord.GatewayIntentBits.MessageContent,
-        ]});
-
-        logger.info('[Chat Relay] Logging into Discord.');
+        const client = new REST({version: '10'}).setToken(token);
 
         try {
-            await client.login(token);
+            // Fails fast at startup instead of silently on the first chat line.
+            const me = await client.get(Routes.user('@me')) as {id: string, username: string};
+            logger.info(`[Chat Relay] Authenticated with Discord as ${me.username} (${me.id}).`);
         } catch (err) {
-            logger.error(`[Chat Relay] Discord login error:\n${(err as Error).stack}`);
-            await clientDestroy();
+            logger.error(`[Chat Relay] Discord token rejected:\n${stackOf(err)}`);
             return;
         }
 
-        logger.info('[Chat Relay] Logged in Discord successfully.');
+        rest = client;
     };
 
-    const sendMessage = async (instance_name: string, datetime: string, message: string) => {
-        if (!client) return;
+    const getChannelId = (instanceName: string): string | null => {
+        const mapping = controller.config.get('chat_relay.discord_channel_mapping') as Record<string, string> | undefined;
+        const channelId = mapping?.[instanceName];
 
-        const mapping = controller.config.get('chat_relay.discord_channel_mapping') as Record<string, string>;
-        const channelId = mapping?.[instance_name];
+        if (!channelId) {
+            if (!warnedNoMapping.has(instanceName)) {
+                warnedNoMapping.add(instanceName);
+                logger.warn(`[Chat Relay] No Discord channel mapped for instance ${instanceName}; dropping its messages.`);
+            }
+
+            return null;
+        }
+
+        return channelId;
+    };
+
+    const sendMessage = async (instanceName: string, datetime: string, message: string) => {
+        if (shuttingDown) return;
+
+        const discord = rest;
+        // Not configured, or the token was rejected. connect() already logged.
+        if (!discord) return;
+
+        const channelId = getChannelId(instanceName);
         if (!channelId) return;
 
-        let channel: Discord.Channel | null;
-
-        try {
-            channel = await client.channels.fetch(channelId);
-        } catch (err) {
-            if ((err as {code?: number}).code !== 10003) {
-                logger.error(`[Chat Relay] Discord channel fetch error:\n${(err as Error).stack}`);
-            }
-            return;
-        }
-
-        if (channel === null || !channel.isSendable()) {
-            logger.error(`[Chat Relay] Discord Channel ID ${channelId} is not a usable channel.`);
-            return;
-        }
-
-        let msg = message;
-
+        // Read the flag once, so it can't flip between chunks of one message.
+        let content = message;
         if (controller.config.get('chat_relay.datetime_on_message')) {
-            msg = `${datetime} ${msg}`;
+            content = `${datetime} ${content}`;
         }
 
-        const send = (content: string) => channel.send({content, allowedMentions: {parse: []}});
+        // trim() here also means an empty chat line produces zero chunks rather than
+        // a 50006 'cannot send an empty message' from Discord.
+        const chunks = splitMessage(content.trim(), MAX_MESSAGE_LENGTH);
 
-        if (msg.length <= MAX_DISCORD_MESSAGE_LENGTH) {
-            await send(msg);
-            return;
-        }
+        for (const chunk of chunks) {
+            try {
+                // discord.js REST handles rate limits (429) and retries for us.
+                await discord.post(Routes.channelMessages(channelId), {
+                    body: {content: chunk, allowedMentions: {parse: []}},
+                });
+            } catch (err) {
+                if (codeOf(err) === ERROR_UNKNOWN_CHANNEL) {
+                    if (!warnedBadChannel.has(channelId)) {
+                        warnedBadChannel.add(channelId);
+                        logger.warn(
+                            `[Chat Relay] Discord channel ${channelId} does not exist or is not visible`
+                            + ` to the bot; dropping messages for ${instanceName}.`,
+                        );
+                    }
+                } else {
+                    logger.error(`[Chat Relay] Discord send failed for ${instanceName}:\n${stackOf(err)}`);
+                }
 
-        let remaining = msg;
-
-        while (remaining.length > 0) {
-            let chunk = remaining.slice(0, MAX_DISCORD_MESSAGE_LENGTH);
-            const lastSpace = chunk.lastIndexOf(' ');
-
-            if (lastSpace > 0) {
-                chunk = chunk.slice(0, lastSpace);
-                remaining = remaining.slice(lastSpace).trim();
-            } else {
-                remaining = remaining.slice(MAX_DISCORD_MESSAGE_LENGTH).trim();
+                // Don't keep hammering a channel that just rejected us.
+                return;
             }
-
-            await send(chunk);
         }
     };
 
     controller.handle(ChatEvent, async (request: ChatEvent) => {
-        const {instance_name, datetime, message} = request;
-        await sendMessage(instance_name, datetime, message);
+        await sendMessage(request.instance_name, request.datetime, request.message);
     });
 
     controller.config.on('fieldChanged', (field) => {
         if (field === 'chat_relay.discord_bot_token') {
-            connect().catch(err => {
-                logger.error(`[Chat Relay] Discord bot token:\n${(err as Error).stack}`);
+            enqueue(connect).catch(err => {
+                logger.error(`[Chat Relay] Discord reconnect failed:\n${stackOf(err)}`);
             });
+        } else if (field === 'chat_relay.discord_channel_mapping') {
+            warnedNoMapping.clear();
+            warnedBadChannel.clear();
         }
     });
 
     controller.hooks.shutdown.attach(plugin.name, async () => {
-        await clientDestroy();
+        // Nothing to tear down without a gateway; just stop accepting new sends.
+        // In-flight REST calls aren't cancellable and will finish or time out.
+        shuttingDown = true;
     });
 
     await connect();