Company

The gold standard for agent-driven signing.

SumoSign is an API-first e-signature platform. A human connects their agent with one scoped key; the agent prepares, sends, and tracks signature requests while recipients sign through branded, no-account links with evidence-grade ceremonies.

Last updated: July 4, 2026

Agent-native, human-signed

Agents should run signing workflows end to end. Every signature still belongs to a real person with consent capture and a defensible audit trail.

Premium execution grade

Multi-party routing, branded domains, and evidence bundles structured for counsel — not a lightweight bolt-on with SES-only disclaimers.

Built for Southeast Asia and beyond

Singapore and Australia are primary markets. We design for regional compliance conversations without overclaiming certifications we have not earned.

Founder

SumoSign is built by Keith Vaughan, founder, sumosign. Founder of SumoSign. Writes on electronic signatures, agent-native signing workflows, and evidence-grade contract execution for contract-heavy teams.

What we ship

The product surface is the REST API, MCP server, and documentation. The customer portal covers signup, API keys, envelope visibility, and webhooks — everything a team needs to operate signing without a legacy vendor portal tax.

Read the API specification, explore security and evidence, or see how we compare to other platforms.

Contact

General inquiries: hello@sumosign.app. API questions: api@sumosign.app. Enterprise rollout: book a demo.