yigitkonur/n8n-schema-generator

extracts JSON schemas from every n8n node and credential by loading the actual n8n-nodes-base package at runtime, reflecting over class instances, and writing structured JSON files. also ships a zero-dependency validation API so LLMs (or anything else) can check generated workflows before deploying them.

schemas auto-update hourly via GitHub Actions when a new n8n version drops. 428 nodes, 389 credentials, all committed to schemas/.

npm run extract   # generate all schemas
npm run serve     # start validation API on :3000

what it does

two parts:

schema extractor (extract.ts) — loads n8n-nodes-base compiled JS, instantiates every node and credential class, extracts properties/defaults/validation rules, writes them as individual JSON files. uses MD5 hashing to skip unchanged files between runs.

validation API (server.ts) — loads extracted schemas into memory, exposes REST endpoints to browse, search, and validate node configs and full workflows. built on raw node:http, no framework.

extractor details

• discovers nodes by walking dist/nodes/*.node.js from the installed package
• handles versioned nodes (VersionedNodeType) — extracts all version variants
• computes defaults using NodeHelpers.getNodeParameters() (same logic n8n uses internally)
• extracts enum values, required fields, filter schemas, fixed collections
• silent error handling — nodes that throw during instantiation are skipped, not fatal

validation details

• validates node type, typeVersion, position, parameters
• merges conditional display options before checking enum values (handles n8n's pattern of same field name appearing multiple times with different allowed values)
• validates workflow structure: nodes array, connections object, duplicate name detection, connection reference integrity
• validates filter conditions and fixed collection keys against schema

API endpoints

install

git clone https://github.com/yigitkonur/n8n-schema-generator.git
cd n8n-schema-generator
npm install

usage

extract schemas

npm run extract              # compile + extract to schemas/
npm run extract:force        # overwrite all, ignore cache
node dist/extract.js mydir   # custom output directory

start validation server

npm run serve                # compile + start on :3000
PORT=8080 npm start          # use pre-built dist, custom port

validate a workflow

curl -X POST http://localhost:3000/validate/workflow \
  -H "Content-Type: application/json" \
  -d @my-workflow.json

validate a single node

curl -X POST http://localhost:3000/validate/node \
  -H "Content-Type: application/json" \
  -d '{"type":"n8n-nodes-base.httpRequest","typeVersion":4.2,"position":[0,0],"parameters":{"method":"GET","url":"https://example.com"}}'

configuration

auto-update

the included GitHub Actions workflow (.github/workflows/update-schemas.yml) runs hourly:

1. compares installed n8n-workflow version against latest on npm
2. if different, runs npm update + npm run extract
3. commits changed schema files back to the repo

schemas in schemas/ are always committed — consumers can read them directly from GitHub without running the extractor.

schema output

schemas/
  _meta.json                 — extraction timestamp, n8n version, node count
  common/
    types.json               — FilterValue, Expression, ParameterTypes
  workflow/
    workflow.json            — JSON Schema draft-07 for n8n workflow format
  credentials/
    _index.json              — all 389 credential names
    <name>.json              — per-credential properties
  nodes/
    _index.json              — all 428 nodes, categories, grouped index
    <name>.json              — full schema per node
    by-category/
      input.json             — nodes grouped by category
      output.json
      transform.json
      trigger.json
      schedule.json
      organization.json
    validation/
      _index.json            — validation index
      <name>.json            — flattened validation rules per node

project structure

extract.ts                   — schema extractor CLI
server.ts                    — validation API server
package.json                 — deps, scripts, engines
tsconfig.json                — ES2022, NodeNext modules, dist/ output
.github/workflows/
  update-schemas.yml         — hourly auto-update cron
schemas/                     — generated output (committed)

license

MIT