diff --git a/docs/writing-plugins.md b/docs/writing-plugins.md
index 5e007b35..62b8c854 100644
--- a/docs/writing-plugins.md
+++ b/docs/writing-plugins.md
@@ -660,7 +660,7 @@ set it accordingly, for example:
     );
 
     // Somewhere in the instance plugin code
-    barMetric.labels(String(this.instance.config.get("instance.id"))).set(someValue);
+    barMetric.labels(String(this.instance.id)).set(someValue);
 
 Metrics are automatically registered to the default registry, and this
 default registry is automatically polled by the master server on slaves.
diff --git a/packages/slave/slave.js b/packages/slave/slave.js
index 6c0dfc30..4e2ad729 100755
--- a/packages/slave/slave.js
+++ b/packages/slave/slave.js
@@ -128,9 +128,15 @@ class Instance extends libLink.Link {
 		this.plugins = new Map();
 		this.config = instanceConfig;
 
+		/**
+		 * ID of this instance, equivalenet to `instance.config.get("instance.id")`.
+		 * @constant {number}
+		 */
+		this.id = this.config.get("instance.id");
+
 		this.logger = logger.child({
-			instance_id: this.config.get("instance.id"),
-			instance_name: this.config.get("instance.name"),
+			instance_id: this.id,
+			instance_name: this.name,
 		});
 
 		this._configFieldChanged = (group, field, prev) => {
@@ -168,7 +174,7 @@ class Instance extends libLink.Link {
 		);
 
 		this.server.on("output", (parsed, line) => {
-			this.logger.log("server", { message: line, instance_id: this.config.get("instance.id"), parsed });
+			this.logger.log("server", { message: line, instance_id: this.id, parsed });
 
 			libPlugin.invokeHook(this.plugins, "onOutput", parsed, line);
 		});
@@ -185,7 +191,7 @@ class Instance extends libLink.Link {
 
 		this.server.on("ipc-player_event", event => {
 			libLink.messages.playerEvent.send(this, {
-				instance_id: this.config.get("instance.id"),
+				instance_id: this.id,
 				...event,
 			});
 			libPlugin.invokeHook(this.plugins, "onPlayerEvent", event);
@@ -193,7 +199,7 @@ class Instance extends libLink.Link {
 	}
 
 	async sendRcon(message, expectEmpty, plugin = "") {
-		let instanceId = String(this.config.get("instance.id"));
+		let instanceId = String(this.id);
 		let observeDuration = instanceRconCommandDuration.labels(instanceId).startTimer();
 		try {
 			return await this.server.sendRcon(message, expectEmpty);
@@ -205,13 +211,13 @@ class Instance extends libLink.Link {
 
 	async _autosave(name) {
 		let stat = await fs.stat(this.path("saves", `${name}.zip`));
-		instanceFactorioAutosaveSize.labels(String(this.config.get("instance.id"))).set(stat.size);
+		instanceFactorioAutosaveSize.labels(String(this.id)).set(stat.size);
 	}
 
 	notifyStatus(status) {
 		this._status = status;
 		libLink.messages.instanceStatusChanged.send(this, {
-			instance_id: this.config.get("instance.id"), status,
+			instance_id: this.id, status,
 		});
 	}
 
@@ -238,7 +244,7 @@ class Instance extends libLink.Link {
 				collector instanceof libPrometheus.ValueCollector
 				&& collector.metric.labels.includes("instance_id")
 			) {
-				collector.removeAll({ instance_id: String(this.config.get("instance.id")) });
+				collector.removeAll({ instance_id: String(this.id) });
 			}
 		}
 
@@ -285,7 +291,7 @@ class Instance extends libLink.Link {
 		for (let [name, plugin] of this.plugins) {
 			plugins[name] = plugin.info.version;
 		}
-		libLink.messages.instanceInitialized.send(this, { instance_id: this.config.get("instance.id"), plugins });
+		libLink.messages.instanceInitialized.send(this, { instance_id: this.id, plugins });
 	}
 
 	/**
@@ -543,9 +549,8 @@ class Instance extends libLink.Link {
 	 * Update instance information on the Factorio side
 	 */
 	async updateInstanceData() {
-		let name = libLuaTools.escapeString(this.config.get("instance.name"));
-		let id = this.config.get("instance.id");
-		await this.sendRcon(`/sc clusterio_private.update_instance(${id}, "${name}")`, true);
+		let name = libLuaTools.escapeString(this.name);
+		await this.sendRcon(`/sc clusterio_private.update_instance(${this.id}, "${name}")`, true);
 	}
 
 	async updateFactorioSettings(current, previous) {
@@ -648,8 +653,8 @@ class Instance extends libLink.Link {
 		let pid = this.server.pid;
 		if (pid) {
 			let stats = await pidusage(pid);
-			instanceFactorioCpuTime.labels(String(this.config.get("instance.id"))).set(stats.ctime / 1000);
-			instanceFactorioMemoryUsage.labels(String(this.config.get("instance.id"))).set(stats.memory);
+			instanceFactorioCpuTime.labels(String(this.id)).set(stats.ctime / 1000);
+			instanceFactorioMemoryUsage.labels(String(this.id)).set(stats.memory);
 		}
 
 		return { results };
diff --git a/plugins/statistics_exporter/instance.js b/plugins/statistics_exporter/instance.js
index e7204d7a..db40dcbd 100644
--- a/plugins/statistics_exporter/instance.js
+++ b/plugins/statistics_exporter/instance.js
@@ -53,7 +53,7 @@ class InstancePlugin extends libPlugin.BaseInstancePlugin {
 			throw new Error(`Error parsing statistics JSON: ${err.message}, content "${string}"`);
 		}
 
-		let instanceId = this.instance.config.get("instance.id");
+		let instanceId = this.instance.id;
 		instanceGameTicksTotal.labels(String(instanceId)).set(stats.game_tick);
 		instancePlayerCount.labels(String(instanceId)).set(stats.player_count);
 
diff --git a/plugins/subspace_storage/instance.js b/plugins/subspace_storage/instance.js
index 668f0b69..1f2529ea 100644
--- a/plugins/subspace_storage/instance.js
+++ b/plugins/subspace_storage/instance.js
@@ -39,7 +39,7 @@ class InstancePlugin extends libPlugin.BaseInstancePlugin {
 	async provideItems(items) {
 		this.info.messages.place.send(this.instance, {
 			items,
-			instance_id: this.instance.config.get("instance.id"),
+			instance_id: this.instance.id,
 		});
 
 		if (this.instance.config.get("subspace_storage.log_item_transfers")) {
@@ -52,7 +52,7 @@ class InstancePlugin extends libPlugin.BaseInstancePlugin {
 	async requestItems(items) {
 		// Request the items all at once
 		let response = await this.info.messages.remove.send(this.instance, {
-			instance_id: this.instance.config.get("instance.id"),
+			instance_id: this.instance.id,
 			items,
 		});
 
diff --git a/test/mock.js b/test/mock.js
index 89ada241..6ca83e96 100644
--- a/test/mock.js
+++ b/test/mock.js
@@ -103,6 +103,7 @@ class MockInstance extends libLink.Link {
 		this.logger = new MockLogger();
 		this.server = new MockServer();
 		this.name = "test";
+		this.id = 7357;
 		this.mockConfigEntries = new Map([
 			["instance.id", 7357],
 			["factorio.enable_save_patching", true],