Attest vs Clicksign

Attest and Clicksign at a glance

Clicksign, based in Barueri, São Paulo, was founded in 2010 and says more than 2 million documents are signed on it each month. It holds ISO 27001 and ISO 27701 certifications. Attest is built around a different promise: proof anyone can check, on documents only the parties can read. Clicksign's prices are as published on its pricing page on October 12, 2026; its other details are as published on its own pages on October 11, 2026.

	Attest	Clicksign (as published October 12, 2026)
Who can read your documents	Only you and the people you send them to. Every document is end-to-end encrypted in your browser	Stored documents secured with "um algoritmo de cifra AES-256" (an AES-256 cipher); no mechanism described that keeps Clicksign out
How a signer signs	Approves with a passkey only they control (Face ID, Touch ID, Windows Hello or the device PIN)	Email token, drawn signature, Pix, ICP-Brasil certificate or ID photo on every plan; SMS, WhatsApp, selfie and biometrics from Plus
What ties the signature to the document	Each signer's own cryptographic signature over the document's fingerprint and their entries	Clicksign's ICP-Brasil certificate seals every finalized document; a signer can also use their own ICP-Brasil certificate
Checking a signed document years later	Anyone, free: the open-source verifier inside the signed copy, with no renewal	ITI's validator, or Clicksign's own Validador, where a document signed more than 12 months ago first needs Clicksign's certificate renewed; if ITI reports "Assinatura Inválida", Clicksign issues an updated version
Prove a fact without the document	Yes: a zero-knowledge proof that you signed, and the date it was completed	Not offered
Free	2 documents, in total	14-day trial, up to 5 documents
Entry paid plan	Signing: $5 a month for 20 documents	Start: R$39 a month for 20 documents, billed monthly

Electronic signatures under Brazilian law, in brief

This is general information, not legal advice. Brazilian law lets most contracts take any form unless a law requires a special one (Código Civil, art. 107). MP 2.200-2/2001, art. 10, sets two rules:

1. Documents signed with an ICP-Brasil certificate are presumed true in relation to the signers (§1).
2. Other ways of proving authorship and integrity, including certificates not issued by ICP-Brasil, are valid "desde que admitido pelas partes como válido ou aceito pela pessoa a quem for oposto o documento": when the parties admit them as valid or the person the document is used against accepts it (§2).

Lei 14.063/2020 names three levels (simple, advanced and qualified, the last meaning ICP-Brasil) for dealings with public bodies. An Attest signature is an electronic signature outside ICP-Brasil: for ordinary contracts between private parties it is valid under §2 when that condition is met, without the presumption of §1. So keep strong evidence and add a clause in which the parties accept the signing method. Some acts need more: real estate deeds above the legal value threshold need a public deed, remote notarial acts go only through e-Notariado, registries require advanced or qualified signatures, and certain public-sector and health documents require qualified ones.

Privacy: who can read your contracts

Clicksign says "Desde que permaneçam salvos na plataforma, a Clicksign assegura todos os documentos com um algoritmo de cifra AES-256" (while they remain stored on the platform, Clicksign secures all documents with an AES-256 cipher), on Amazon Web Services servers in Brazil and the United States. Its llms.txt file adds "Utiliza criptografia de dados de ponta a ponta" (uses end-to-end data encryption), but none of the pages we read explains what that covers or who holds the keys. Its Plus and higher plans include Click.AI document summaries, a feature that has to read a document's contents.

Attest encrypts every document in your browser before upload, with AES-256-GCM, and locks the key separately to each person you send it to. Attest stores your document only as ciphertext it can't read, and it has no AI features that process documents. We compared 21 e-signature services in October 2026, Attest and 20 others, and Attest was the only one that end-to-end encrypts every document, for every signer, by default.

How signers sign

Clicksign signers need no account: "Quem assina o documento (signatário) não precisa ter uma conta ou plano contratado". Clicksign advertises 16 authentication methods, from an email token and Pix on every plan to SMS, WhatsApp, dynamic selfie and facial biometrics against public and private databases from Plus. Signing with the signer's own ICP-Brasil certificate is included on every plan; the signer buys the certificate from an accredited certification authority.

On Attest, every signer approves with a passkey: a cryptographic key only the signer controls, unlocked with Face ID, Touch ID, Windows Hello or the device PIN. The passkey signs a statement naming the exact document, by its fingerprint, and everything the signer entered, so every signature, on every document, is the signer's own, with no certificate to buy. There is no account or password to create, and signers never pay.

Proof that lasts without renewal

Clicksign stamps every finalized document with its ICP-Brasil certificate, and anyone can check that seal on the government validator at validar.iti.gov.br, run by ITI. Clicksign also describes the limits: if ITI returns "Assinatura Inválida", the user asks Clicksign for an updated version with current ICP-Brasil keys; Adobe Acrobat shows the certification as invalid until the user imports the ICP-Brasil root certificate; and for documents signed more than 12 months ago, "antes do processo de validação deverá ser realizada a renovação do Certificado Digital da Clicksign, através do próprio Validador" (before validating, Clicksign's certificate must be renewed through Clicksign's own validator).

An Attest signed copy needs nothing renewed. Every party downloads the same sealed PDF: the signed pages, with a "Signed with Attest" stamp on each signature and a seal line at the foot of every page, a certificate of completion, the audit trail up to completion and a "Verify it yourself, without us" page, with the full evidence, the original document and a standalone verifier attached inside. Drop the PDF on that verifier in any browser, years from now, even if Attest no longer exists: it checks the original document against what every signer signed, each signer's passkey signature and entries, Attest's anchored record of the agreement on the Horizen public blockchain, and that nothing was added after sealing, and it re-makes every page you see from what was signed and compares the result byte for byte.

Proving an agreement without sharing it

With Share proof, a signer creates a zero-knowledge proof that they, or they and a named co-signer, signed an agreement, and the date it was completed. A bank, a landlord or a partner sees the email addresses, the completion date, and that the proof is valid and where its record is anchored, never the document, its title or its terms. Each proof is verified on zkVerify. Clicksign does not offer this.

Price

Attest's price is in US dollars. At the Banco Central do Brasil's PTAX selling rate of October 9, 2026 (R$4.9892 per dollar, the latest before October 12), $5 is about R$24.95.

	Attest	Clicksign (as published October 12, 2026)
Free	2 documents, in total	14-day trial, up to 5 documents
20 documents a month	Signing: $5 a month (about R$24.95)	Start: R$39 a month, billed monthly
Per document, at 20 a month	About R$1.25	R$1.95
Past the plan's documents	New documents wait for next month, or Pro at $49 a month	R$3.00 per extra document on Start 20

As published on October 12, 2026, Clicksign's Plus plan (R$59 a month for 20 documents) adds WhatsApp sending and biometric checks, and Automação (R$85) adds templates, forms and bulk sending. Attest's plans are month to month, and you can cancel any time.

When Clicksign is the better fit

• You need ICP-Brasil signatures, for the presumption of truth or because a public body, registry or rule requires a qualified signature.
• You need identity checks against Brazilian sources, such as a CPF check with the Receita Federal, Serpro biometrics or document forensics.
• Your signers live on WhatsApp: sending and signing through WhatsApp from Plus, and Pix authentication on every plan.
• You automate in bulk: templates, forms and spreadsheet bulk sends on Automação.
• You want everything in Portuguese, with servers in Brazil and the United States, and an accredited ICP-Brasil timestamp on custom plans.

Who should choose Attest

• Companies and professionals in Brazil signing confidential agreements, such as NDAs, partnership agreements and service contracts, that Brazilian law lets them sign electronically and that no provider should be able to read: every Attest document is end-to-end encrypted in the browser, while Clicksign describes AES-256 encryption of stored documents.
• Agreements with parties in other countries, signed in any browser with a passkey.
• Anyone who wants proof that stays checkable for years, without renewing a vendor's certificate.
• Small senders who want 20 documents a month for $5 (about R$25 at the PTAX rate of October 9, 2026).

Starting on Attest

Sign in with your email, set up your signing key with a passkey and a recovery phrase, upload a PDF of up to 8 MB, add your signers and place their fields. Your first 2 documents are free, in total.