METRC is the Marijuana Enforcement and Tracking RC software designed, built and maintained by Franwell, Inc. In 2018 they received an investment of $50M from Tiger Global & Casa Verde 
This was the first state to go live with METRC in 2014.
METRC took over for LeafData in Nevada after LeafData had fallen on it's face.
METRC allows API access to their systems. Each vendor must be validated, for each region. Some regions, such as Alaska allow vendors to simply sign the agreement and are enabled -- provided they've passed the validation in another METRC State. It seems that only Colorado and Oregon environments provide a test-sandbox.
This API is REST-like, pull the index of objects, pull a specific object. One caveat to note is that on write, when objects are created, the response is empty -- no information about the created resource is provided. A similar caveat exists on update, which can be mitigated by a post update read request (write/re-read).
- 2020-09-24 - File:API Bulletin 081.pdf - Update to Rate Limiting Phases
- 2020-09-18 - File:API Bulletin 080.pdf - Update to multi limit tracking for patients in Montana
- 2020-09-03 - File:API Bulletin 079.pdf - Update on Patient Status Lookup API
- 2020-09-01 - File:API Bulletin 078.pdf - Update to Customer Type Configuration
- 2020-08-31 - File:API Bulletin 077.pdf - Update to Customer Type Configuration
- 2020-08-21 - File:API Bulletin 076.pdf - Rate Limiting Reminder and API Webpage
- 2020-08-11 - File:API Bulletin 075.pdf - Rate Limiting Phase One Notice
- 2020-07-31 - File:API Bulletin 074.pdf - Rate Limiting Update
- 2020-07-30 - File:API Bulletin 073.pdf - Updates to Cultivation, Item Category, Package, Location, and Sales Receipts Endpoints Impacting the Metrc API Program for the State of California
- 2020-07-20 - File:API Bulletin 072.pdf - Release Notice Update
- 2020-07-17 - File:API Bulletin 071.pdf - Release Notice and Upcoming System Maintenance
- 2020-07-15 - File:API Bulletin 070.pdf - Release Notice and Upcoming System Maintenance
- 2020-07-09 - File:API Bulletin 069.pdf - Updates to Sales Receipts Endpoint and Fix for Using Same Item
- 2020-06-09 - File:API Bulletin 068.pdf - Updates to Cultivation Endpoint URLs and Other Endpoint Changes
- 2020-05-15 - File:API Bulletin 067.pdf - Montana Real Time Sales, Patient Status Lookup, and Purchasing Limits
- 2020-04-23 - File:API Bulletin 066.pdf - Upcoming California Release and Configuration Changes
- 2020-04-14 - File:API Bulletin 065.pdf - District of Columbia Sales Delivery Guidance
- 2020-03-30 - File:API Bulletin 064.pdf - Nevada Sales Delivery Guidance
- 2020-03-24 - File:API Bulletin 063.pdf - Colorado Inventory Reconciliation Guidance
- 2020-03-24 - File:API Bulletin 062.pdf - Metrc API Program for Maine
- 2019-08-19 - File:API Bulletin 048.pdf - lab results and package-note
- 2019-06-19 - File:API Bulletin 045.pdf - regarding retail sale returns.