Sign by is a service to have users sign PDF documents online. You can use the Sign application or, if you want an integration with your own systems, request access to our API. This documentation focuses on the API integration.

For a complete technical documentation with specifications for all field types, JSON objects and methods, you can consult our complete API reference: API reference

If you need technical assistance, please contact your account manager or support ([email protected]).

Service description


A dossier is a collection of information related to the signing process of a document. Dossiers consist, among other things, of:

  • Files: the PDF document(s) to be signed
  • Invitees: the persons who have to sign or review the dossier
  • Owners (optional): the contact person who will be informed about status updates of the dossier
  • Attachments (optional): files attached to the dossier which doesn't have to be signed

A dossier expires after 30 days by default, this can be customised when creating the dossier (up to 90 days).


Files are the PDF documents presented to the user to be signed.

When a dossier is completed, the fields are added to the file, which is then digitally signed with a certificate. This certificate is trusted by Adobe Reader, as it is part of the Adobe Approved Trust List. The signature allows end users to verify the integrity of the document, proves the document has not been altered, and by whom and when the document has been signed.


Invitees are persons asked to sign or review a dossier. Invitees' properties:

  • Name: the name that will be used in communication to address the invitee
  • Fields: locations within a PDF document for information to be added. See fields.
  • Email (optional): the email address that will be used to notify the invitee about this dossier and send the signed document
  • Locale (optional): the locale to be used in invitations and the UI, the default locale is en-US
  • Position (optional): positions determine the order of signing, lower positions will be invited earlier
  • Authentication methods (optional): additional authentication before the user can view the dossier
  • Identification methods (optional): additional identification in order to sign the dossier
  • Notifications (optional): which notifications should be sent, by default all notifications are sent
  • Payments (optional): additional payment before signing the dossier
  • Phone number (optional): the phone number to be used to send an invite or OTP to
  • Reference (optional): allows the invitee it to be linked to an ID known within your organisation
  • Read-only (optional): when read-only the invitee will review instead of sign the dossier
  • Redirect URL (optional): URL to redirect the invitee to after signing, approving or declining the dossier


Fields are locations within a PDF document where information will be added. Fields belong to a specific file and invitee and have parameters to configure its position(s) in the document.

Supported field types:

  • signature: the invitee is asked for a signature
  • initials: the invitee is asked for its initials. Initials can be specified for a page range and the invitee has to confirm its initials each page.
  • signatureDate: the date the invitee signed the document, automatically determined
  • text: a text field that can be filled in by the invitee
  • textarea: a multi-line text field that can be filled in by the invitee
  • label: a text field that contains a predefined text which cannot be modified
  • checkbox: a box which can be checked by the user
  • radio: a group of radio buttons, of which one option must be selected
  • stamp: the invitee is asked for its stamp/seal (hanko), mostly used in Asia and Africa


An invite is a unique URL linked to an invitee to view the dossier. Sign can send these invites to the invitees or you can distribute the URL yourself, for example by redirecting or sending emails yourself. An invite can have a custom expiration time, specified during creation. Creating multiple invites for an invitee is possible.

Supported message channels:

  • email: the invite is send to the email address of the invitee.
  • sms: the invite is send via sms to the phone number of the invitee (only available when configured).
  • whatsapp: the invite is send via WhatsApp Business Platform to the phone number of the invitee (only available when configured).
  • default: the invite URL will be returned in the response for you to distribute yourself.


A dossier owner is a contact person who will be informed about status updates of the dossier. If set, the owner's name will be used in communication to the invitees, otherwise the organisation name is used instead.


Attachments are files attached to the dossier which doesn't have to be signed, for example, a Terms and Conditions document.

Audit report

The audit report contains all info and events related to the dossier for evidence purposes, like documents, owners, invitees, fields and events.

Data retention

Sign is only a signing service and does not store or retain dossiers and documents beyond the expiration date of the dossier, to comply with the General Data Protection Regulation (GDPR). Documents and personal data are anonymized or deleted. It's thus required to download dossiers after completion and to store them within your own company records.


Sign provides two environments:

  • Sandbox:
  • Production:

The sandbox environment is intended to do your initial experimentation with. Unlike the production environment, it doesn't add a cryptographic signature to the document and you will not be billed for using the sandbox environment.

Please note that the credentials for sandbox and production environment are different.