diff --git a/config.js b/config.js
index 37b0e04..7325287 100644
--- a/config.js
+++ b/config.js
@@ -1,3 +1,9 @@
+/*
+	Welcome to the config file!
+	Add keys here to override values from /src/lib/constants.js. Please look at that file for override recommendations.
+	This file should hopefully never be altered upstream.
+	You must restart Bibliogram to apply these changes.
+*/
+
 module.exports = {
-	website_origin: "http://localhost:10407"
 }
diff --git a/package-lock.json b/package-lock.json
index ed86373..7f0a849 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -868,6 +868,11 @@
       "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
       "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ="
     },
+    "mixin-deep": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/mixin-deep/-/mixin-deep-2.0.1.tgz",
+      "integrity": "sha512-imbHQNRglyaplMmjBLL3V5R6Bfq5oM+ivds3SKgc6oRtzErEnBUUc5No11Z2pilkUvl42gJvi285xTNswcKCMA=="
+    },
     "mkdirp": {
       "version": "0.5.1",
       "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz",
diff --git a/package.json b/package.json
index ce6924d..5c70c10 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,7 @@
   "license": "AGPL-3.0-only",
   "dependencies": {
     "gm": "^1.23.1",
+    "mixin-deep": "^2.0.1",
     "node-dir": "^0.1.17",
     "node-fetch": "^2.6.0",
     "pinski": "github:cloudrac3r/pinski#19495f7a1c62fbfd8c685cf5bb5d678788906032",
diff --git a/src/lib/collectors.js b/src/lib/collectors.js
index 44dc2fc..3d73443 100644
--- a/src/lib/collectors.js
+++ b/src/lib/collectors.js
@@ -4,9 +4,9 @@ const {extractSharedData} = require("./utils/body")
 const {TtlCache, RequestCache} = require("./cache")
 require("./testimports")(constants, request, extractSharedData, RequestCache)
 
-const requestCache = new RequestCache(constants.resource_cache_time)
+const requestCache = new RequestCache(constants.caching.resource_cache_time)
 /** @type {import("./cache").TtlCache<import("./structures/TimelineEntry")>} */
-const timelineEntryCache = new TtlCache(constants.resource_cache_time)
+const timelineEntryCache = new TtlCache(constants.caching.resource_cache_time)
 
 function fetchUser(username) {
 	return requestCache.getOrFetch("user/"+username, () => {
@@ -39,6 +39,7 @@ function fetchTimelinePage(userID, after) {
 	}))
 	return requestCache.getOrFetchPromise("page/"+after, () => {
 		return request(`https://www.instagram.com/graphql/query/?${p.toString()}`).then(res => res.json()).then(root => {
+			if (!root.data) console.error("missing data:", root) //todo: please make this better.
 			/** @type {import("./types").PagedEdges<import("./types").TimelineEntryN2>} */
 			const timeline = root.data.user.edge_owner_to_timeline_media
 			return timeline
diff --git a/src/lib/constants.js b/src/lib/constants.js
index 00a3f53..f9402bf 100644
--- a/src/lib/constants.js
+++ b/src/lib/constants.js
@@ -1,7 +1,20 @@
-module.exports = {
-	image_cache_control: `public, max-age=${7*24*60*60}`,
-	resource_cache_time: 30*60*1000,
+/*
+	Welcome to the constants file!
+	Copy a key and provide a new value in /config.js to override the value here.
+	Please read the comments above every section!
+*/
 
+let constants = {
+	// Things that server owners _should_ change!
+	website_origin: "http://localhost:10407",
+
+	// Things that server owners _could_ change if they want to.
+	caching: {
+		image_cache_control: `public, max-age=${7*24*60*60}`,
+		resource_cache_time: 30*60*1000
+	},
+
+	// Instagram uses this stuff. This shouldn't be changed, except to fix a bug that hasn't yet been fixed upstream.
 	external: {
 		timeline_query_hash: "e769aa130647d2354c40ea6a439bfc08",
 		shortcode_query_hash: "2b0673e0dc4580674a88d426fe00ea90",
@@ -10,6 +23,7 @@ module.exports = {
 		shortcode_regex: "[\\w-]+"
 	},
 
+	// My code uses this stuff. Server owners have no reason to change it.
 	symbols: {
 		NO_MORE_PAGES: Symbol("NO_MORE_PAGES"),
 		TYPE_IMAGE: Symbol("TYPE_IMAGE"),
@@ -21,3 +35,9 @@ module.exports = {
 		NO_SHARED_DATA: Symbol("NO_SHARED_DATA")
 	}
 }
+
+// Override values from config and export the result
+const md = require("mixin-deep")
+const config = require("../../config")
+constants = md(constants, config)
+module.exports = constants
diff --git a/src/lib/structures/User.js b/src/lib/structures/User.js
index 7dd9b46..5e1d8fe 100644
--- a/src/lib/structures/User.js
+++ b/src/lib/structures/User.js
@@ -18,7 +18,7 @@ class User {
 	}
 
 	getTtl(scale = 1) {
-		const expiresAt = this.cachedAt + constants.resource_cache_time
+		const expiresAt = this.cachedAt + constants.caching.resource_cache_time
 		const ttl = expiresAt - Date.now()
 		return Math.ceil(Math.max(ttl, 0) / scale)
 	}
diff --git a/src/site/api/proxy.js b/src/site/api/proxy.js
index ca7d26d..df9d1dd 100644
--- a/src/site/api/proxy.js
+++ b/src/site/api/proxy.js
@@ -33,7 +33,7 @@ module.exports = [
 					statusCode: 200,
 					contentType: "image/jpeg",
 					headers: {
-						"Cache-Control": constants.image_cache_control
+						"Cache-Control": constants.caching.image_cache_control
 					},
 					stream: image.stream("jpg")
 				}
@@ -54,7 +54,7 @@ module.exports = [
 			})
 		} else {
 			return proxy(url, {
-				"Cache-Control": constants.image_cache_control
+				"Cache-Control": constants.caching.image_cache_control
 			})
 		}
 	}}
diff --git a/src/site/repl.js b/src/site/repl.js
index cad3361..986ef61 100644
--- a/src/site/repl.js
+++ b/src/site/repl.js
@@ -1,5 +1,6 @@
 const {instance, pugCache, wss} = require("./passthrough")
 const {requestCache, timelineEntryCache} = require("../lib/collectors")
+const constants = require("../lib/constants")
 const util = require("util")
 const repl = require("repl")
 const vm = require("vm")