quickhelp.dev — 15 free developer tools, each with a UI, API, and MCP server

Every tool runs in your browser, exposes a REST API, and is wired into a single MCP server so AI agents and humans get first-class access without any sign-up.

Live: quickhelp.dev · API: quickhelp.dev/openapi.json · MCP: quickhelp.dev/mcp

Tools

Tool	UI	API endpoint
JWT Decoder	/jwt-decoder	`POST /api/jwt-decoder`
JSON Formatter	/json-formatter	`POST /api/json-formatter`
Base64 Encoder / Decoder	/base64	`POST /api/base64`
Image Converter	/image-converter	`POST /api/image-converter`
Image Resizer	/image-resizer	`POST /api/image-resizer`
Background Remover	/background-remover	`POST /api/background-remover`
Hash Generator	/hash-generator	`POST /api/hash-generator`
UUID Generator	/uuid-generator	`POST /api/uuid-generator`
URL Encoder / Decoder	/url-encoder	`POST /api/url-encoder`
Timestamp Converter	/timestamp-converter	`POST /api/timestamp-converter`
JSON to CSV	/json-to-csv	`POST /api/json-to-csv`
Text Case Converter	/text-case-converter	`POST /api/text-case-converter`
Color Converter	/color-converter	`POST /api/color-converter`
Number Base Converter	/number-base-converter	`POST /api/number-base-converter`
LCOV Viewer	/lcov-viewer	`POST /api/lcov-viewer`

Related MCP server: mcp-server-devutils

Three interfaces, one domain

Human UI — browser-based, no sign-up, no upload to a server. Image tools use WebAssembly in your browser; text tools run client-side JS.

REST API — every tool is POST /api/<slug>, JSON in, JSON out. Free tier: 30 req/60s watermarked. OpenAPI 3.1 spec at /openapi.json.

MCP server — a single MCP endpoint covers all 15 tools. AI agents (Claude, Cursor, Continue, etc.) can discover and call any tool via the Model Context Protocol.

GET  https://quickhelp.dev/openapi.json    # OpenAPI 3.1 — all tools
GET  https://quickhelp.dev/llms.txt        # llms.txt discovery surface
GET  https://quickhelp.dev/llms-full.txt   # full per-tool docs for LLMs
POST https://quickhelp.dev/mcp             # MCP HTTP (JSON-RPC 2.0)

Use the MCP server

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "quickhelp": {
      "command": "npx",
      "args": ["-y", "quickhelp-mcp"]
    }
  }
}

Claude Code (CLI)

claude mcp add --transport http quickhelp https://quickhelp.dev/mcp

Hosted HTTP endpoint (any MCP client)

POST https://quickhelp.dev/mcp
Content-Type: application/json

{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}

Quick API example

# Decode a JWT
curl -X POST https://quickhelp.dev/api/jwt-decoder \
  -H 'Content-Type: application/json' \
  -d '{"token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIn0.dozjgNryP4J3jVmNHl0w5N_XgL0n3I9PlFUP0THsR8U"}'

# Convert a colour
curl -X POST https://quickhelp.dev/api/color-converter \
  -H 'Content-Type: application/json' \
  -d '{"color":"#FF5733","from":"hex","to":"hsl"}'

# Generate UUIDs
curl -X POST https://quickhelp.dev/api/uuid-generator \
  -H 'Content-Type: application/json' \
  -d '{"version":"v4","count":5}'

Repo structure

quickhelp/
├── apps/web/          # Next.js 14 — human UI + REST API + discovery routes
├── apps/mcp/          # Standalone MCP stdio server (same registry)
├── packages/tool-kit/ # defineTool() contract + Zod helpers
├── packages/agent-sdk/# buildOpenAPI(), buildLlmsTxt(), buildMcpTools()
├── packages/ui/       # Shared UI components
├── packages/seo/      # MetaTags + JSON-LD
├── packages/tools/    # One package per tool
└── tooling/           # CLI scaffolder (pnpm create-tool <slug>)

Local development

pnpm install
pnpm dev          # web app at localhost:3000

Adding a new tool

pnpm create-tool <slug>
# Fill in packages/tools/<slug>/src/manifest.ts
# Tool auto-appears in UI, API, OpenAPI, llms.txt, and MCP — no extra wiring

Design principles

No auth, no database, no LLM calls — every tool is stateless and finishes in <5s.
Privacy-first — image processing runs in your browser via WebAssembly; nothing is uploaded.
Single-domain aggregation — one /openapi.json, one /mcp, one /llms.txt so agents resolve tool discovery in one request.
Free tier, always — anonymous use is free (watermarked output, 30 req/60s).

⭐ If this is useful, a GitHub star helps other developers find it.

QuickHelp