Authenticate by setting your Middesk API key in the Authorization header as a Bearer token (Authorization: Bearer YOUR_API_KEY).
Create a business object via POST to the /v1/businesses endpoint with the business's legal name, EIN/tax ID, registered address, and optionally officers or beneficial owners.
Middesk asynchronously processes the verification; poll GET /v1/businesses/{id} or listen for the business.updated webhook event to receive status updates.
When status reaches 'completed', retrieve the business object and inspect the review object which contains tasks (e.g., tin, name, address, watchlist, sos_domestic) each with a status of 'success', 'warning', or 'failure'.
Use the tasks breakdown to make a KYB pass/fail decision; route businesses with 'warning' tasks to manual review for human adjudication.
Store the Middesk business ID and the snapshot of results for your compliance records.
Known gotchas
EIN formatting matters; submit EIN without dashes (nine digits) unless documentation specifies otherwise.
Secretary of State (SOS) checks are only available for US businesses; do not expect SOS task results for foreign entities.
Middesk may return partial results while still processing; wait for the 'completed' status before making a final KYB decision.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp