Sincerely is AI direct mail for B2B revenue teams. For each target account, it researches the company and writes a postcard, letter, handwritten note, or gift note for one person, with every claim linked to its source. One campaign sequences all four formats to the same account. Nothing prints until a person approves it. An account-level holdout reports the lift with an interval. Run it in the app or from Claude or ChatGPT over MCP.
