diff --git a/bin/generate-openapi.js b/bin/generate-openapi.js
new file mode 100644
index 000000000..ae6818482
--- /dev/null
+++ b/bin/generate-openapi.js
@@ -0,0 +1,51 @@
+import swaggerJsdoc from 'swagger-jsdoc';
+
+/*
+ * Usage: npm run generate-openapi | tail -n1 > x.json
+ *
+ * Inspect generated file by opening it in https://editor-next.swagger.io/
+ *
+ */
+
+const options = {
+  definition: {
+    openapi: '3.1.1',
+    info: {
+      title: 'Trilium Notes - Sync server API',
+      version: '0.96.6',
+      description: "This is the internal sync server API used by Trilium Notes / TriliumNext Notes.\n\n_If you're looking for the officially supported External Trilium API, see [here](https://triliumnext.github.io/Docs/Wiki/etapi.html)._\n\nThis page does not yet list all routes. For a full list, see the [route controller](https://github.com/TriliumNext/Notes/blob/v0.91.6/src/routes/routes.ts).",
+      contact: {
+        name: "TriliumNext issue tracker",
+        url: "https://github.com/TriliumNext/Notes/issues",
+      },
+      license: {
+        name: "GNU Free Documentation License 1.3 (or later)",
+        url: "https://www.gnu.org/licenses/fdl-1.3",
+      },
+    },
+  },
+  apis: ['./src/routes/api/*.ts', './bin/generate-openapi.js'],
+};
+
+const openapiSpecification = swaggerJsdoc(options);
+
+console.log(JSON.stringify(openapiSpecification));
+
+/**
+ * @swagger
+ * components:
+ *   schemas:
+ *     UtcDateTime:
+ *       type: string
+ *       example: "2025-02-13T07:42:47.698Z"
+ *   securitySchemes:
+ *     user-password:
+ *       type: apiKey
+ *       name: trilium-cred
+ *       in: header
+ *       description: "Username and password, formatted as `user:password`"
+ *     session:
+ *       type: apiKey
+ *       in: cookie
+ *       name: trilium.sid
+ */
diff --git a/package-lock.json b/package-lock.json
index d633ccfe2..5fdf64248 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -165,6 +165,7 @@
         "prettier": "3.5.0",
         "rcedit": "4.0.1",
         "rimraf": "6.0.1",
+        "swagger-jsdoc": "6.2.8",
         "tslib": "2.8.1",
         "tsx": "4.19.2",
         "typedoc": "0.27.7",
@@ -222,6 +223,54 @@
         "url": "https://github.com/sponsors/antfu"
       }
     },
+    "node_modules/@apidevtools/json-schema-ref-parser": {
+      "version": "9.1.2",
+      "resolved": "https://registry.npmjs.org/@apidevtools/json-schema-ref-parser/-/json-schema-ref-parser-9.1.2.tgz",
+      "integrity": "sha512-r1w81DpR+KyRWd3f+rk6TNqMgedmAxZP5v5KWlXQWlgMUUtyEJch0DKEci1SorPMiSeM8XPl7MZ3miJ60JIpQg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@jsdevtools/ono": "^7.1.3",
+        "@types/json-schema": "^7.0.6",
+        "call-me-maybe": "^1.0.1",
+        "js-yaml": "^4.1.0"
+      }
+    },
+    "node_modules/@apidevtools/openapi-schemas": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/@apidevtools/openapi-schemas/-/openapi-schemas-2.1.0.tgz",
+      "integrity": "sha512-Zc1AlqrJlX3SlpupFGpiLi2EbteyP7fXmUOGup6/DnkRgjP9bgMM/ag+n91rsv0U1Gpz0H3VILA/o3bW7Ua6BQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=10"
+      }
+    },
+    "node_modules/@apidevtools/swagger-methods": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/@apidevtools/swagger-methods/-/swagger-methods-3.0.2.tgz",
+      "integrity": "sha512-QAkD5kK2b1WfjDS/UQn/qQkbwF31uqRjPTrsCs5ZG9BQGAkjwvqGFjjPqAuzac/IYzpPtRzjCP1WrTuAIjMrXg==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@apidevtools/swagger-parser": {
+      "version": "10.0.3",
+      "resolved": "https://registry.npmjs.org/@apidevtools/swagger-parser/-/swagger-parser-10.0.3.tgz",
+      "integrity": "sha512-sNiLY51vZOmSPFZA5TF35KZ2HbgYklQnTSDnkghamzLb3EkNtcQnrBQEj5AOCxHpTtXpqMCRM1CrmV2rG6nw4g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@apidevtools/json-schema-ref-parser": "^9.0.6",
+        "@apidevtools/openapi-schemas": "^2.0.4",
+        "@apidevtools/swagger-methods": "^3.0.2",
+        "@jsdevtools/ono": "^7.1.3",
+        "call-me-maybe": "^1.0.1",
+        "z-schema": "^5.0.1"
+      },
+      "peerDependencies": {
+        "openapi-types": ">=7"
+      }
+    },
     "node_modules/@asamuzakjp/css-color": {
       "version": "2.8.2",
       "resolved": "https://registry.npmjs.org/@asamuzakjp/css-color/-/css-color-2.8.2.tgz",
@@ -2715,6 +2764,13 @@
       "integrity": "sha512-gv3ZRaISU3fjPAgNsriBRqGWQL6quFx04YMPW/zD8XMLsU32mhCCbfbO6KZFLjvYpCZ8zyDEgqsgf+PwPaM7GQ==",
       "license": "MIT"
     },
+    "node_modules/@jsdevtools/ono": {
+      "version": "7.1.3",
+      "resolved": "https://registry.npmjs.org/@jsdevtools/ono/-/ono-7.1.3.tgz",
+      "integrity": "sha512-4JQNk+3mVzK3xh2rqd6RB4J46qUR19azEHBneZyTZM+c456qOrbbM/5xcR8huNCCcbVt7+UmizG6GuUvPvKUYg==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@jsdoc/salty": {
       "version": "0.2.9",
       "resolved": "https://registry.npmjs.org/@jsdoc/salty/-/salty-0.2.9.tgz",
@@ -6021,6 +6077,13 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/call-me-maybe": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/call-me-maybe/-/call-me-maybe-1.0.2.tgz",
+      "integrity": "sha512-HpX65o1Hnr9HH25ojC1YGs7HCQLq0GCOibSaWER0eNpgJ/Z1MZv2mTc7+xh6WOPxbRVcmgbv4hGU+uSQ/2xFZQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/caniuse-lite": {
       "version": "1.0.30001689",
       "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001689.tgz",
@@ -7799,6 +7862,19 @@
         "p-limit": "^3.1.0 "
       }
     },
+    "node_modules/doctrine": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/doctrine/-/doctrine-3.0.0.tgz",
+      "integrity": "sha512-yS+Q5i3hBf7GBkd4KG8a7eBNNWNGLTaEwwYWUijIYM7zrlYDM0BFXHjjPWlWZ1Rg7UaddZeIDmi9jF3HmqiQ2w==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "esutils": "^2.0.2"
+      },
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
     "node_modules/dom-serializer": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/dom-serializer/-/dom-serializer-2.0.0.tgz",
@@ -8992,6 +9068,16 @@
         "@types/estree": "^1.0.0"
       }
     },
+    "node_modules/esutils": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/esutils/-/esutils-2.0.3.tgz",
+      "integrity": "sha512-kVscqXk4OCp68SZ0dkgEKVi6/8ij300KBWTJq32P/dYeWTSwK41WyTxalN1eRmA5Z9UU/LX9D7FWSmV9SAYx6g==",
+      "dev": true,
+      "license": "BSD-2-Clause",
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
     "node_modules/etag": {
       "version": "1.8.1",
       "resolved": "https://registry.npmjs.org/etag/-/etag-1.8.1.tgz",
@@ -11962,6 +12048,21 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/lodash.isequal": {
+      "version": "4.5.0",
+      "resolved": "https://registry.npmjs.org/lodash.isequal/-/lodash.isequal-4.5.0.tgz",
+      "integrity": "sha512-pDo3lu8Jhfjqls6GkMgpahsF9kCyayhgykjyLMNFTKWrpVdAQtYyB4muAMWozBB4ig/dtWAmsMxLEI8wuz+DYQ==",
+      "deprecated": "This package is deprecated. Use require('node:util').isDeepStrictEqual instead.",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/lodash.mergewith": {
+      "version": "4.6.2",
+      "resolved": "https://registry.npmjs.org/lodash.mergewith/-/lodash.mergewith-4.6.2.tgz",
+      "integrity": "sha512-GK3g5RPZWTRSeLSpgP8Xhra+pnjBC56q9FZYe1d5RN3TJ35dbkGy3YqBSMbyCrlbi+CM9Z3Jk5yTL7RCsqboyQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/log-symbols": {
       "version": "4.1.0",
       "resolved": "https://registry.npmjs.org/log-symbols/-/log-symbols-4.1.0.tgz",
@@ -13101,6 +13202,14 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/openapi-types": {
+      "version": "12.1.3",
+      "resolved": "https://registry.npmjs.org/openapi-types/-/openapi-types-12.1.3.tgz",
+      "integrity": "sha512-N4YtSYJqghVu4iek2ZUvcN/0aqH1kRDuNqzcycDxhOUpg7GdvLa2F3DgS6yBNhInhv2r/6I0Flkn7CqL8+nIcw==",
+      "dev": true,
+      "license": "MIT",
+      "peer": true
+    },
     "node_modules/ora": {
       "version": "5.4.1",
       "resolved": "https://registry.npmjs.org/ora/-/ora-5.4.1.tgz",
@@ -16088,6 +16197,82 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/swagger-jsdoc": {
+      "version": "6.2.8",
+      "resolved": "https://registry.npmjs.org/swagger-jsdoc/-/swagger-jsdoc-6.2.8.tgz",
+      "integrity": "sha512-VPvil1+JRpmJ55CgAtn8DIcpBs0bL5L3q5bVQvF4tAW/k/9JYSj7dCpaYCAv5rufe0vcCbBRQXGvzpkWjvLklQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "commander": "6.2.0",
+        "doctrine": "3.0.0",
+        "glob": "7.1.6",
+        "lodash.mergewith": "^4.6.2",
+        "swagger-parser": "^10.0.3",
+        "yaml": "2.0.0-1"
+      },
+      "bin": {
+        "swagger-jsdoc": "bin/swagger-jsdoc.js"
+      },
+      "engines": {
+        "node": ">=12.0.0"
+      }
+    },
+    "node_modules/swagger-jsdoc/node_modules/commander": {
+      "version": "6.2.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-6.2.0.tgz",
+      "integrity": "sha512-zP4jEKbe8SHzKJYQmq8Y9gYjtO/POJLgIdKgV7B9qNmABVFVc+ctqSX6iXh4mCpJfRBOabiZ2YKPg8ciDw6C+Q==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/swagger-jsdoc/node_modules/glob": {
+      "version": "7.1.6",
+      "resolved": "https://registry.npmjs.org/glob/-/glob-7.1.6.tgz",
+      "integrity": "sha512-LwaxwyZ72Lk7vZINtNNrywX0ZuLyStrdDtabefZKAY5ZGJhVtgdznluResxNmPitE0SAO+O26sWTHeKSI2wMBA==",
+      "deprecated": "Glob versions prior to v9 are no longer supported",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "fs.realpath": "^1.0.0",
+        "inflight": "^1.0.4",
+        "inherits": "2",
+        "minimatch": "^3.0.4",
+        "once": "^1.3.0",
+        "path-is-absolute": "^1.0.0"
+      },
+      "engines": {
+        "node": "*"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/isaacs"
+      }
+    },
+    "node_modules/swagger-jsdoc/node_modules/yaml": {
+      "version": "2.0.0-1",
+      "resolved": "https://registry.npmjs.org/yaml/-/yaml-2.0.0-1.tgz",
+      "integrity": "sha512-W7h5dEhywMKenDJh2iX/LABkbFnBxasD27oyXWDS/feDsxiw0dD5ncXdYXgkvAsXIY2MpW/ZKkr9IU30DBdMNQ==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/swagger-parser": {
+      "version": "10.0.3",
+      "resolved": "https://registry.npmjs.org/swagger-parser/-/swagger-parser-10.0.3.tgz",
+      "integrity": "sha512-nF7oMeL4KypldrQhac8RyHerJeGPD1p2xDh900GPvc+Nk7nWP6jX2FcC7WmkinMoAmoO774+AFXcWsW8gMWEIg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@apidevtools/swagger-parser": "10.0.3"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/swagger-ui-dist": {
       "version": "5.18.3",
       "resolved": "https://registry.npmjs.org/swagger-ui-dist/-/swagger-ui-dist-5.18.3.tgz",
@@ -17187,6 +17372,16 @@
         "spdx-expression-parse": "^3.0.0"
       }
     },
+    "node_modules/validator": {
+      "version": "13.12.0",
+      "resolved": "https://registry.npmjs.org/validator/-/validator-13.12.0.tgz",
+      "integrity": "sha512-c1Q0mCiPlgdTVVVIJIrBuxNicYE+t/7oKeI9MWLj3fh/uq2Pxh/3eeWbVZ4OcGW1TUf53At0njHw5SMdA3tmMg==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.10"
+      }
+    },
     "node_modules/value-equal": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/value-equal/-/value-equal-1.0.1.tgz",
@@ -18629,6 +18824,38 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/z-schema": {
+      "version": "5.0.5",
+      "resolved": "https://registry.npmjs.org/z-schema/-/z-schema-5.0.5.tgz",
+      "integrity": "sha512-D7eujBWkLa3p2sIpJA0d1pr7es+a7m0vFAnZLlCEKq/Ij2k0MLi9Br2UPxoxdYystm5K1yeBGzub0FlYUEWj2Q==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "lodash.get": "^4.4.2",
+        "lodash.isequal": "^4.5.0",
+        "validator": "^13.7.0"
+      },
+      "bin": {
+        "z-schema": "bin/z-schema"
+      },
+      "engines": {
+        "node": ">=8.0.0"
+      },
+      "optionalDependencies": {
+        "commander": "^9.4.1"
+      }
+    },
+    "node_modules/z-schema/node_modules/commander": {
+      "version": "9.5.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-9.5.0.tgz",
+      "integrity": "sha512-KRs7WVDKg86PWiuAqhDrAQnTXZKraVcCc6vFdL14qrZ/DcWwuRo7VoiYXalXO7S5GKpqYiVEwCbgFDfxNHKJBQ==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true,
+      "engines": {
+        "node": "^12.20.0 || >=14"
+      }
+    },
     "node_modules/zip-stream": {
       "version": "6.0.1",
       "resolved": "https://registry.npmjs.org/zip-stream/-/zip-stream-6.0.1.tgz",
diff --git a/package.json b/package.json
index 2555c4ed3..9829a639f 100644
--- a/package.json
+++ b/package.json
@@ -53,6 +53,7 @@
     "integration-mem-db": "cross-env TRILIUM_INTEGRATION_TEST=memory TRILIUM_PORT=8082 TRILIUM_DATA_DIR=./integration-tests/db nodemon src/main.ts",
     "integration-mem-db-dev": "cross-env TRILIUM_INTEGRATION_TEST=memory TRILIUM_PORT=8082 TRILIUM_ENV=dev TRILIUM_DATA_DIR=./integration-tests/db nodemon src/main.ts",
     "generate-document": "cross-env nodemon ./bin/generate_document.ts 1000",
+    "generate-openapi": "node bin/generate-openapi.js",
     "ci-update-nightly-version": "tsx ./bin/update-nightly-version.ts",
     "prettier-check": "prettier . --check",
     "prettier-fix": "prettier . --write"
@@ -211,6 +212,7 @@
     "prettier": "3.5.0",
     "rcedit": "4.0.1",
     "rimraf": "6.0.1",
+    "swagger-jsdoc": "6.2.8",
     "tslib": "2.8.1",
     "tsx": "4.19.2",
     "typedoc": "0.27.7",
diff --git a/src/routes/api/app_info.ts b/src/routes/api/app_info.ts
index 87501e804..560a52d1f 100644
--- a/src/routes/api/app_info.ts
+++ b/src/routes/api/app_info.ts
@@ -2,6 +2,51 @@
 
 import appInfo from "../../services/app_info.js";
 
+/**
+ * @swagger
+ * /api/app-info:
+ *   get:
+ *     summary: Get installation info
+ *     operationId: app-info
+ *     externalDocs:
+ *       description: Server implementation
+ *       url: https://github.com/TriliumNext/Notes/blob/v0.91.6/src/services/app_info.ts
+ *     responses:
+ *       '200':
+ *         content:
+ *           application/json:
+ *             schema:
+ *               type: object
+ *               properties:
+ *                 appVersion:
+ *                   type: string
+ *                   example: "0.91.6"
+ *                 dbVersion:
+ *                   type: integer
+ *                   example: 228
+ *                 nodeVersion:
+ *                   type: string
+ *                   description: "value of process.version"
+ *                 syncVersion:
+ *                   type: integer
+ *                   example: 34
+ *                 buildDate:
+ *                   type: string
+ *                   example: "2024-09-07T18:36:34Z"
+ *                 buildRevision:
+ *                   type: string
+ *                   example: "7c0d6930fa8f20d269dcfbcbc8f636a25f6bb9a7"
+ *                 dataDirectory:
+ *                   type: string
+ *                   example: "/var/lib/trilium"
+ *                 clipperProtocolVersion:
+ *                   type: string
+ *                   example: "1.0"
+ *                 utcDateTime:
+ *                   $ref: '#/components/schemas/UtcDateTime'
+ *     security:
+ *       - session: []
+ */
 function getAppInfo() {
     return appInfo;
 }
diff --git a/src/routes/api/login.ts b/src/routes/api/login.ts
index 3a6d43e99..1f190aec2 100644
--- a/src/routes/api/login.ts
+++ b/src/routes/api/login.ts
@@ -14,6 +14,68 @@ import ws from "../../services/ws.js";
 import etapiTokenService from "../../services/etapi_tokens.js";
 import type { Request } from "express";
 
+/**
+ * @swagger
+ * /api/login/sync:
+ *   post:
+ *     tags:
+ *       - auth
+ *     summary: Log in using documentSecret
+ *     description: The `hash` parameter is computed using a HMAC of the `documentSecret` and `timestamp`.
+ *     operationId: login-sync
+ *     externalDocs:
+ *       description: HMAC calculation
+ *       url: https://github.com/TriliumNext/Notes/blob/v0.91.6/src/services/utils.ts#L62-L66
+ *     requestBody:
+ *       content:
+ *         application/json:
+ *           schema:
+ *             type: object
+ *             properties:
+ *               timestamp:
+ *                 $ref: '#/components/schemas/UtcDateTime'
+ *               hash:
+ *                 type: string
+ *               syncVersion:
+ *                 type: integer
+ *                 example: 34
+ *     responses:
+ *       '200':
+ *         description: Successful operation
+ *         content:
+ *           application/json:
+ *             schema:
+ *               type: object
+ *               properties:
+ *                 syncVersion:
+ *                   type: integer
+ *                   example: 34
+ *                 options:
+ *                   type: object
+ *                   properties:
+ *                     documentSecret:
+ *                       type: string
+ *       '400':
+ *         description: Sync version / document secret mismatch
+ *         content:
+ *           application/json:
+ *             schema:
+ *               type: object
+ *               properties:
+ *                 message:
+ *                   type: string
+ *                   example: "Non-matching sync versions, local is version ${server syncVersion}, remote is ${requested syncVersion}. It is recommended to run same version of Trilium on both sides of sync"
+ *       '401':
+ *         description: Timestamp mismatch
+ *         content:
+ *           application/json:
+ *             schema:
+ *               type: object
+ *               properties:
+ *                 message:
+ *                   type: string
+ *                   example: "Auth request time is out of sync, please check that both client and server have correct time. The difference between clocks has to be smaller than 5 minutes"
+ */
 function loginSync(req: Request) {
     if (!sqlInit.schemaExists()) {
         return [500, { message: "DB schema does not exist, can't sync." }];
diff --git a/src/routes/api/setup.ts b/src/routes/api/setup.ts
index e4e5a6729..718bc37a7 100644
--- a/src/routes/api/setup.ts
+++ b/src/routes/api/setup.ts
@@ -45,6 +45,34 @@ function saveSyncSeed(req: Request) {
     sqlInit.createDatabaseForSync(options);
 }
 
+/**
+ * @swagger
+ * /api/setup/sync-seed:
+ *   get:
+ *     tags:
+ *       - auth
+ *     summary: Sync documentSecret value
+ *     description: First step to logging in.
+ *     operationId: setup-sync-seed
+ *     responses:
+ *       '200':
+ *         description: Successful operation
+ *         content:
+ *           application/json:
+ *             schema:
+ *               type: object
+ *               properties:
+ *                 syncVersion:
+ *                   type: integer
+ *                   example: 34
+ *                 options:
+ *                   type: object
+ *                   properties:
+ *                     documentSecret:
+ *                       type: string
+ *     security:
+ *       - user-password: []
+ */
 function getSyncSeed() {
     log.info("Serving sync seed.");