Sunnystamp API: online web service for contracts and subscriptions

Sunnystamp API

These web services and APIs facilitate the creation of paperless contracts and online signatures

More online businesses, professionals, artisans, associations and administrations are turning to paperless contractual relationships, whether virtual, online or by telephone, or in person in an agency or shop, where both parties are present.

  • Documents are signed electronically and online, with the same legal effect as a paper document
  • Sunnystamp retains the traceability of exchanges (signature, co-signing, counter-signature, stamp etc.) and stores the evidence for 10 years
  • Sunnystamp works SaaS mode with per-transaction invoicing, and without the need for investment
  • Sunnystamp allows users to electronically sign with a secure digital identity, whether signing on a cryptographic device or “on the fly”
  • Sunnystamp offers many possibilities for customisation and integration with business applications thanks to its modular, open architecture

Trust services offered by Sunnystamp

  • Issues digital identities on the fly: temporary or permanent certificate validated by Sunnystamp or an affiliated or external certification authority
  • Support for certificates issued by trusted third parties on USB or smart card
  • Third-party verification of ID information available to reinforce security
  • Certifies documents to create tamper-proof electronic originals
  • Allows signing and co-signing
  • Verification of documents signed with token and self-supporting archive
  • Time-stamps signatures to ensure the priority of the signature and the validity of the signer’s certificate
  • Issues hard-copy certificates for third parties

PAdES signature

The platform supports Sunnystamp PAdES [1] signature format, corresponding to a PDF signed with an integrated signature.

The PAdES signature format is the Basic version referenced by ETSI [2] in the document TS 102 778-2 which provides the following benefits:

  • Signature is embedded in the PDF. No special validation tool is required (other than Adobe Reader, which is free).
  • Signature is time-stamped. This ensures that the priority of the signature against a reference date of trust.
  • Freestanding signature incorporates elements relative to the cerificate’s revocation status when time-stamped. This ensures the validity of certificates for future verification.

Other formats available: XAdES [3] and CAdES [4]

Three signing scenarios

1. Online signing only, suited to online subscriptions

2. Online and email signing, suited to a process where the subscription is started after the user has given approval, in person or remotely

3. Batch signing, suited to sending documents in batches, eg. renewing a subscription


Sunnystamp’s integrated services

If you’d like to test our API, please contact us !


[1] PAdES : PDF Advanced Electronic Signature

[2] ETSI : European Telecommunications Standards Institute

[3] XAdES : XML Advanced Electronic Signature

[4] CAdES : CMS Advanced Electronic Signature