MCP Server

qr3.app exposes an MCP server for AI tools like Claude and Cursor. The current server uses a standard HTTP transport and bearer authentication.

Secure connection

Endpoint: https://mcp.qr3.app/mcp

The current remote server uses HTTP bearer authentication:

Authorization: Bearer <API_KEY>

Use only an MCP client that can send a custom HTTP Authorization header from its secure credential store. Never commit an API key to a project configuration file or repository.

Claude Remote Connectors use OAuth. qr3 currently offers bearer-key authentication only, so it is not directly compatible with that connector flow until OAuth support is added.

Discovery without an API key

A client does not have to ask for credentials first in order to find out what this server offers. https://mcp.qr3.app/mcp answers the following methods without an Authorization header:

Method	Returns
`initialize`	Protocol version, capabilities, server name
`tools/list`	every tool together with its input schema
`resources/list`	the catalogue of static resources
`resources/read`	the content of a single resource
`prompts/list`	the prompt list
`ping`	reachability

Every method that touches a workspace goes through tools/call, and that still requires the bearer key. Without it the server answers with HTTP 401, application/problem+json and WWW-Authenticate: Bearer realm="qr3.app".

curl -s https://mcp.qr3.app/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"resources/list","params":{}}'

For clients that do not speak MCP, the same catalogue is available as plain JSON at https://mcp.qr3.app/resources, and a single resource at https://mcp.qr3.app/resources/<uri-without-qr3://>.

Available tools

Core tools

Tool	Description
`create_qr`	Create a QR code for a URL
`update_qr`	Update a QR code’s target URL, status, tags, notes, or expiry
`list_qrs`	List QR codes with a status filter and cursor pagination
`get_qr_stats`	Get aggregated scan statistics for a QR code
`create_batch`	Create QR codes from a list of URLs (max. 50)
`create_dpp_qr`	Create a DPP QR code for a battery, textile, or general product
`create_vcard_qr`	Create a static vCard QR code
`create_wifi_qr`	Create a static WiFi QR code
`validate_dpp`	Validate DPP data without creating it
`get_image`	Get an API-provided PNG, SVG, PDF, or EPS asset URL
`shorten_url`	Create a dynamic URL QR code and return its short URL

DPP resources

The server also exposes static resources for the DPP contract:

URI	Content
`qr3://qr-types`	The six Codes API types: URL, vCard, WiFi, email, SMS, and location
`qr3://error-codes`	Error types and handling guidance
`qr3://rate-limits`	Plan-based rate limits
`qr3://quickstart`	Quickstart guide
`qr3://dpp-schema`	Battery-first DPP contract
`qr3://gs1-test-vectors`	GS1 resolver examples
`qr3://dpp-content-negotiation-examples`	Resolver response examples

Example prompts

Create a QR code for https://example.com

Show me the scan stats for qr_abc123

Create a battery DPP with GTIN 04012345678901 and the required battery data