For humans

Easy signing for everything, by people and their AI agents.

Drop a PDF, or let your agent send it. Your signer gets a link, and you get back a sealed file with an audit trail. No account to send and none to sign. We shred it after 7 days unless you keep it.

Connect your AI agent →Bring your team →

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For agents & developers

POST /v1/documents

# no key needed to try this. we email a
# code and hand back a throwaway
# sign_tmp_ key for this document.
$ curl -F title='Repair authorization' \
       -F sender_email=you@example.com \
       -F signers='[{"name":"Jane",
         "email":"jane@example.com"}]' \
       -F file=@form.pdf \
       https://agentsign.co/v1/documents

# your agent can sign off too, with its
# own named key. it gets a cryptographic
# receipt, not a pretend signature.
$ curl -X POST \
    https://agentsign.co/v1/documents/doc_kx3q9/attest \
    -H 'authorization: Bearer sign_agent_...'
> receipt 4c19…9e2f · recorded 14:02:59 UTC

Schema: /openapi.json

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Always free, open source

No per-seat pricing

For humans and agents alike

So what is this?

Accounts are optional

You drop a PDF. Your signer taps a link. An account is never the price of a signature; make one only when you want a place to keep what you've signed. The file comes back sealed, with proof of everything that happened.

SENT

We email your signer a link. They never need an account. Neither did you.

SIGNED

They review the PDF, consent, and sign by hand on any device.

SEALED

You both get the sealed file, the certificate, and the full audit trail. We shred our copy in seven days unless you keep it.

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For agents & developers

GET /v1/documents/{id}

# they signed. this is the trail: who,
# when, and every step we recorded.
# the throwaway key from send can read
# this document only.
$ curl https://agentsign.co/v1/documents/doc_kx3q9 \
       -H 'authorization: Bearer sign_live_...'
{ "status": "completed", "signers": [ … ], "audit": [ … ] }

> completed 14:09:41 UTC · kept 7 days unless you keep it

Tmp key from send can GET this id until shred.

What do agents have to do with it?

It speaks agent and developer

Every month, more of your paperwork is handled by something that isn't a person. AgentSign is built for that turn, and the audit trail names everyone who took it.

PEOPLE

Sign by hand, like always. The pen stays yours.

AGENTS

Hold a named key and sign off with a cryptographic receipt, never a faked signature.

DEVELOPERS

Get the whole rail: REST, OpenAPI, MCP tools, and webhooks.

Works over MCP

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Connect your AI agent MCP tools →

View as machine

For agents & developers

POST /v1/documents/{id}/attest

# named key, own receipt. it never
# signs for a person. people still
# finish the PDF by hand.
$ curl -X POST \
    https://agentsign.co/v1/documents/doc_kx3q9/attest \
    -H 'authorization: Bearer sign_agent_...'

> receipt 4c19…9e2f · recorded 14:02:59 UTC

/llms.txt

MCP: send · status · attest · verify

Why believe any of it?

The file is the proof.

Every sealed PDF carries its own evidence. Post it back any time; anyone can run the check, no key and no account.

THE SEAL

The file is byte for byte the one that was signed. Any edit breaks it.

THE SIGNATURES

Who signed, when they signed, and the consent they gave.

THE RECEIPTS

Which named agents signed off, and when.

The code is open, so you can run the whole service yourself.

See pricing Read the docs →

View as machine

For agents & developers

POST /v1/verify

# anyone can run this. no key, no
# account. the file is the proof.
$ curl -F file=@sealed.pdf \
       https://agentsign.co/v1/verify
{ "valid": true, "human_signatures": 1, "agent_attestations": 1 }

> anyone can run this. no key.

Docs