Closient exposes the same product graph through two surfaces: a hosted Model Context Protocol server and an HTTPS REST API. They cover the same data; they’re optimised for different consumers.Documentation Index
Fetch the complete documentation index at: https://docs.closient.com/llms.txt
Use this file to discover all available pages before exploring further.
Should I use the MCP server or the REST API?
| If you’re… | Use |
|---|---|
| Building an AI agent (Claude, Cursor, IDE assistant, custom MCP client) | MCP server |
| Integrating product lookup into a backend service | REST API |
| Embedding barcode resolution in a mobile or web app | REST API |
| Connecting a no-code workflow tool (n8n, Make, Zapier) | REST API |
| Hooking a desktop AI app into product data | MCP server |
| Building a CLI that humans run interactively | Either — REST is simpler for non-AI tools |
What’s the difference between an AI agent calling MCP and an AI agent calling the REST API?
Both work; the AI client experience is what differs. MCP gives the agent a tool list at connect time, with structured input/output schemas and human-readable descriptions. The agent picks tools by name and the LLM doesn’t need any “how to call this API” documentation in its prompt — the protocol handles tool discovery, parameter validation, and result framing. REST forces you to put the API surface into the agent’s prompt (or its function-calling schema), which costs tokens and means every release of the agent needs an updated tool definition. For agents that already speak MCP — Claude Code, Cursor, Claude Desktop, VS Code, Windsurf — MCP is strictly less work.What can each surface do?
| Capability | MCP | REST |
|---|---|---|
| Validate a GTIN | validate_gtin | GET /products/api/v1/products?gtin=... |
| Resolve a GTIN | resolve_gtin | GET /01/<gtin> |
| Look up product data | lookup_product | GET /products/api/v1/products/<id> |
| Natural-language search | search_products | POST /search/api/v1/sessions |
| Compare products | compare_products | Multiple GET /products calls + client-side join |
| Check local availability | check_availability | GET /retailers/api/v1/offers |
| Generate Digital Link QR | generate_qr_url (OAuth) | POST /api/v1/qr-codes (API key) |
| Create / edit catalog data | Not exposed | POST / PATCH endpoints |
| Webhooks / event streams | Not exposed | /integrations/webhooks |
| Bulk operations | Not exposed | Pagination + batch endpoints |
How do auth and rate limits compare?
| Aspect | MCP | REST |
|---|---|---|
| Default auth | None (most tools) | API key required |
| Authenticated tools / endpoints | OAuth 2.1 step-up | X-API-Key: <prefix>_<body>_<checksum> |
| Rate limit | Shared backend limits | 300/min, 10,000/day per key |
| Client registration | CIMD / DCR / pre-registration | Dashboard → Settings → API Keys |
Can I use both?
Yes — and many integrations do. A common pattern:- MCP server for the agent’s read path (lookup, search, resolve).
- REST API for the backend that owns mutations (catalog edits, webhook subscriptions, bulk imports) where you don’t want LLM-induced side effects.
Where do I go next?
MCP Install
One-command install for every supported MCP client.
API Reference
Eighteen domain APIs with interactive playgrounds.
Quickstart
First REST API call in under five minutes.
MCP Quickstart
First MCP tool call in under two minutes.