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For Developers

A GTIN in, JSON out.

GET /01/{gtin} with Accept: application/json returns the product. Add ?linkType=all for the linkset. EPCIS 2.0 capture and an MCP server run on the same host.

Read the Docs Get an API Key

One request. Structured product data.

$ curl -H "X-API-Key: csb_your_key" \
  https://www.closient.com/01/00012345678905

{
  "gtin": "00012345678905",
  "product_name": "Organic Whole Milk",
  "brand": "Green Valley Dairy",
  "net_content": "1 gallon",
  "country_of_origin": "US",
  "confidence_score": 0.97
}

Try it without a key:

$ curl -H 'Accept: application/json' https://www.closient.com/01/09506000164908

The problems you're dealing with

Building product-aware applications shouldn't require stitching together unreliable data sources.

No reliable product data API

Most product databases are paywalled, stale, or incomplete. You end up scraping, deduplicating, and maintaining your own product catalog just to get basic GTIN lookups.

GS1 Digital Link resolution is complex

Implementing a conformant resolver from scratch requires deep GS1 knowledge, URI parsing, link-type negotiation, and ongoing spec compliance work.

AI agents need product context

LLM-powered shopping assistants, inventory agents, and recommendation engines need structured product data they can query — not HTML pages to scrape.

EPCIS integration is painful

Implementing EPCIS 2.0 from scratch is a multi-month project. Capture events, query histories, and maintain compliance — or let an API handle it.

What you can build with

APIs and tools designed for software engineers, integration architects, and AI/ML practitioners.

REST API

Query and manage product data through a REST API with a published OpenAPI spec.

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GS1 Digital Link Resolver API

Resolve any GTIN to structured product data via a conformant GS1 Digital Link resolver. Supports AI qualifiers including lot, serial, and expiry.

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MCP Server & AI Agent Integration

An MCP server over streamable HTTP at /mcp/http, described at /.well-known/mcp.json. Agents can validate Digital Links, resolve GTINs, search products and check availability.

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EPCIS 2.0 API

Capture EPCIS 2.0 events, read them back, and trace a lot forward to the products that carry it.

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CLI & SDKs Coming soon

Manage your product data from the command line or integrate directly with client libraries for Python, JavaScript, and more.

Learn more

Why build on Closient

Standards-based

Built on GS1 Digital Link and EPCIS 2.0 — open standards, not proprietary formats. Your integrations are portable.

Transparent pricing

Every price is published. No sales calls required. Free tier available for development and small projects.

Open data

No key needed to read. Basic product data resolves without an account.

Frequently asked questions

The REST API returns JSON by default. The GS1 Digital Link resolver supports content negotiation including JSON, JSON-LD, and GS1 linkset formats. The EPCIS 2.0 API supports both JSON and JSON-LD as specified by the GS1 EPCIS standard.

Yes. A free tier is available for development and small projects, including product lookups, batch tracking and API access. No credit card required to get started.

Create a free account, then generate an API key from your account dashboard. Keys use the format csb__ and are passed via the X-API-Key header.

The Model Context Protocol (MCP) server lets AI agents and LLMs query Closient product data as a tool. This enables shopping assistants, inventory agents, and other AI-powered applications to access structured product data programmatically. It's live now — see the install guide.

Start building today

Explore the API documentation or create a free account to get your API key. No credit card required.

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