diff --git a/server/services/monitoringService.ts b/server/services/monitoringService.ts
index 2a043f9..416ff81 100644
--- a/server/services/monitoringService.ts
+++ b/server/services/monitoringService.ts
@@ -16,7 +16,7 @@ import {normalizeMac} from "../utils/strings";
 import {monitoringDisableUrl} from "../utils/urlBuilder";
 import CONSTRAINTS from "../validation/constraints";
 import {forConstraint} from "../validation/validator";
-import {MAC, MailType, Node, NodeId, NodeState, NodeStateData, UnixTimestamp} from "../types";
+import {MAC, MailType, Node, NodeId, NodeState, NodeStateData, UnixTimestampSeconds} from "../types";
 
 const MONITORING_STATE_MACS_CHUNK_SIZE = 100;
 const NEVER_ONLINE_NODES_DELETION_CHUNK_SIZE = 20;
@@ -688,7 +688,7 @@ export async function deleteOfflineNodes(): Promise<void> {
     await deleteNodesOfflineSinceBefore(deleteBefore);
 }
 
-async function deleteNeverOnlineNodesBefore(deleteBefore: UnixTimestamp): Promise<void> {
+async function deleteNeverOnlineNodesBefore(deleteBefore: UnixTimestampSeconds): Promise<void> {
     Logger
         .tag('nodes', 'delete-never-online')
         .info(
@@ -765,7 +765,7 @@ async function deleteNeverOnlineNodesBefore(deleteBefore: UnixTimestamp): Promis
     }
 }
 
-async function deleteNodesOfflineSinceBefore(deleteBefore: UnixTimestamp): Promise<void> {
+async function deleteNodesOfflineSinceBefore(deleteBefore: UnixTimestampSeconds): Promise<void> {
     const rows = await db.all(
         'SELECT * FROM node_state WHERE state = ? AND last_seen < ?',
         [
diff --git a/server/services/nodeService.ts b/server/services/nodeService.ts
index d1bbeb4..9f20bc7 100644
--- a/server/services/nodeService.ts
+++ b/server/services/nodeService.ts
@@ -10,7 +10,7 @@ import Logger from "../logger";
 import * as MailService from "../services/mailService";
 import {normalizeString} from "../utils/strings";
 import {monitoringConfirmUrl, monitoringDisableUrl} from "../utils/urlBuilder";
-import {FastdKey, MonitoringState, MonitoringToken, Node, NodeSecrets, NodeStatistics, UnixTimestamp, Token} from "../types";
+import {FastdKey, MonitoringState, MonitoringToken, Node, NodeSecrets, NodeStatistics, UnixTimestampSeconds, Token} from "../types";
 import util from "util";
 
 const pglob = util.promisify(glob);
@@ -235,7 +235,7 @@ async function deleteNodeFile(token: Token): Promise<void> {
 async function parseNodeFile(file: string): Promise<{node: Node, nodeSecrets: NodeSecrets}> {
     const contents = await fs.readFile(file);
     const stats = await fs.lstat(file);
-    const modifiedAt = stats.mtimeMs;
+    const modifiedAt = Math.floor(stats.mtimeMs / 1000);
 
     const lines = contents.toString();
 
@@ -491,7 +491,7 @@ export async function fixNodeFilenames(): Promise<void> {
     }
 }
 
-export async function findNodesModifiedBefore(timestamp: UnixTimestamp): Promise<Node[]> {
+export async function findNodesModifiedBefore(timestamp: UnixTimestampSeconds): Promise<Node[]> {
     const nodes = await getAllNodes();
     return _.filter(nodes, node => node.modifiedAt < timestamp);
 }
diff --git a/server/types/index.ts b/server/types/index.ts
index de03658..8b27f9d 100644
--- a/server/types/index.ts
+++ b/server/types/index.ts
@@ -6,7 +6,8 @@ export type Token = string;
 export type FastdKey = string;
 export type MAC = string;
 
-export type UnixTimestamp = number;
+export type UnixTimestampSeconds = number;
+export type UnixTimestampMilliseconds = number;
 
 export type MonitoringToken = string;
 export enum MonitoringState {
@@ -39,7 +40,7 @@ export type Node = {
     monitoring: boolean;
     monitoringConfirmed: boolean;
     monitoringState: MonitoringState;
-    modifiedAt: UnixTimestamp;
+    modifiedAt: UnixTimestampSeconds;
 };
 
 // TODO: Complete interface / class declaration.