Lessen API
Lessen documents a GraphQL One Open API v2 with client and vendor surfaces, sandbox and webhooks. Credentials are developer accounts Lessen issues to contracted clients and vendors, with no signup; v1 APIs are sunset and vendor API metering is coming.
Frequently asked questions
Lessen scores C on Supergood's API Report Card. Lessen documents a GraphQL One Open API v2 with client and vendor surfaces, sandbox and webhooks. Credentials are developer accounts Lessen issues to contracted clients and vendors, with no signup; v1 APIs are sunset and vendor API metering is coming.
Lessen has an official API, but teams routinely hit its limits: gated access, partial coverage, or paid tiers. Most end up supplementing it with exports or an unofficial API layer like Supergood. Site terms may apply to any integration approach, and how they apply is a determination each team makes for itself.
Lessen is a property services company whose One by Lessen platform manages the full work order lifecycle for residential and commercial portfolios: intake (including the Aiden AI assistant), vendor sourcing from a network of more than 30,000 providers, dispatch, proposals, invoicing, turns and renovation projects, assets and compliance.
Real Estate & Property; enterprise single-family rental and multifamily owners (named clients include Invitation Homes and American Homes 4 Rent) and multi-site commercial operators in retail, banking, restaurants and healthcare. A resident or facility manager submits a request; Aiden gathers symptoms and drafts the work order; Lessen coordinators or the client's own team dispatch a vetted vendor at pre-negotiated pricing; the vendor accepts, schedules, completes and invoices in One Onsite; the client approves proposals and invoices in the Client Portal and reviews scorecards and spend analytics.
Lessen states it serves 280,000 properties, completes more than three million work orders a year across 100+ metro areas, and holds 40 million work orders of history. Its customer count is in the hundreds rather than thousands, but the portfolios are very large.
Work orders with location, asset, resident and technician detail; resident names, phone numbers, emails, lease and move-out dates; vendor employee rosters, insurance and pricing; proposals and invoices (financial data); attachments and photos of interiors; commercial site access instructions.
The One platform dates to SMS Assist (founded 1999 as a facilities maintenance company) and was rebuilt as containerized microservices on a service mesh.
Vendors on the SMS Assist BBB profile report refused or deferred payment for dozens of completed services and unresponsive vendor managers. A contractor reports not being paid for work, being charged for calls, and views the rebrand to Lessen as the same company. Full sourced list under Sources below.
Common alternatives include ServiceChannel, Corrigo, Property Meld, HappyCo, Latchel. Graded alternatives appear under "More from the report card" below.
Supergood's grades measure one thing: can a customer's engineering team get their own data out programmatically? Supergood checks six things (whether a real API exists, how access is gated, data coverage, auth quality, docs and developer experience, and stability) and rolls them into a letter grade. Supergood re-verifies grades, and they only move on evidence.
Not that we could find. There is no official Lessen MCP server in any public registry, and no maintained community server we're aware of. We re-verify this periodically — report an inaccuracy below if we missed one.
Not natively. Lessen doesn't publish an MCP server, so MCP clients like Claude, Cursor, and Codex have nothing to connect to out of the box. If that changes, this page will reflect it.