E-Signature in Portugal: AssinaJá, DigitalSign, Multicert and the Chave Móvel Digital

A buyer comparing e-signature platforms in Portugal starts from a position that does not exist in most other markets: the state is already the incumbent. The Chave Móvel Digital (CMD) signs at the highest tier eIDAS defines, works from a phone, and carries no published price. So the Portuguese shortlist is not four companies competing to sign your document. It is the state, plus the companies selling what the state does not do — AssinaJá, DigitalSign and SIBS Multicert being the ones a Portuguese buyer actually meets.

Every figure below was read on each vendor’s own live page on the check date shown above. Prices in this category move, so confirm the current plan before you buy.

The state already handed out 9.7 million qualified signatures

The numbers are the state’s own. Its statistics page reports a “Número Total de Adesões” for the Chave Móvel Digital of 9.743.199, against “Número Total de Autenticações” of 140.783.983. In a country of roughly ten and a half million people, that is a signing credential in most adult pockets.

And it is not a lesser signature. The state’s own page says so plainly: “Com a Chave Móvel Digital pode assinar documentos digitais com a mesma validade de uma assinatura à mão. A assinatura digital com Chave Móvel Digital é certificada pelo Regulamento 910/2014 da União Europeia.” On the digital signature page it adds: “O Estado português garante a certificação de assinaturas digitais realizadas com Cartão de Cidadão ou Chave Móvel Digital (CMD).” You can sign a PDF in a browser, “dispensando a instalação de software”, or in the Autenticação.gov desktop application, which is where the timestamp, reason and location options live.

Nothing on any of those pages puts a price on activating a CMD or on signing with one.

What the state publishes just as plainly is the limits, and these are what create the commercial market:

• A company cannot have one. From the CMD FAQ: “A Chave Móvel Digital só está disponível para pessoas individuais. Não é possível ativar uma Chave Móvel Digital associada a sociedades comerciais ou para outro tipo de pessoa coletiva.” If the signature has to bind the company rather than the person, you are buying a certificate of representation or an electronic seal from someone.
• It is tethered to the Cartão de Cidadão. Cancel the card and, per the same FAQ, “a assinatura digital da Chave Móvel Digital fica logo cancelada também” — authentication survives to the card’s expiry plus 30 days; signing does not.
• Signing is a second switch. The state’s page says “Pode ativar a assinatura digital da Chave Móvel Digital (CMD) assim que ativar a CMD” — holding a CMD is not the same as being able to sign with it. And if the CMD was activated through the Portal das Finanças or a TV box, the state says the signature function “só pode ativar a assinatura digital num balcão” — in person.
• Readers may not agree with the file. The state warns: “Alguns softwares de leitura de ficheiros PDF podem não reconhecer a assinatura digital. No entanto, a assinatura digital é válida.” Expect to explain that to a counterparty at some point.
• It signs; it does not run a process. The competitor that says this best is AssinaJá, on its own about page: the Autenticação.gov application “É competente a assinar, mas não gere circuitos: não envia documentos para terceiros assinarem, não acompanha o estado de cada assinatura, não gera contratos a partir de templates nem envia documentos em série.” It has an interest in saying so, and it is accurate about the application’s scope.

The state also publishes a list of “outras aplicações certificadas para assinatura com CMD” — among them BlueAuth, edoclink, eGOV.WEBDOC, Fact.pt, iPortalDoc eSIGNING, NONIO, SigmaDoc, wireMEET and Docuten, which is also one of the four names on the Spanish shortlist we cover in e-signature in Spain.

The four options, from their own pages

• Chave Móvel Digital (the state). Activation through the gov.pt mobile app with the Cartão de Cidadão and a camera, through the Autenticação.gov portal with a card reader, through the Portal das Finanças, or at an Espaço Cidadão, IRN or other public counter. Signing happens in the browser or in the desktop application. Qualified signature, no published price, personal only, no workflow. AssinaJá’s guide states flatly that “A adesão é gratuita”; the state’s own pages simply never mention money.
• AssinaJá. The Portuguese platform, operated by RMB Sistemas de Informação, Lda. Its pricing page, marked “Atualizado em 5 de agosto de 2026”, sells five plans with a Mensal/Anual switch, and the two views are not the same product. On Mensal: Free at 0€ (“5 assinaturas CMD”, “10 assinaturas sem certificado”, 1 user, 250 MB, with the footnote “Estes limites são atribuídos uma única vez e não se renovam”), Core at 19€/mês (3 CMD signatures, 10 certificate-less, 1 user, 1 GB), Launch at 49€/mês and marked “Mais Popular” (5 CMD, 25 certificate-less, 3 users, 2 GB, document templates), Growth at 99€/mês (10 CMD, “Assinatura com Atributos Profissionais (SCAP)”, 100 certificate-less, 10 users, 5 GB, “25 notificações SMS”, BYOS storage on Azure) and Enterprise at 199€/mês (20 CMD, SCAP, 250 certificate-less, 50 users, 15 GB, 50 SMS, unlimited templates). Switch to Anual and the prices become 199€, 499€, 1099€ and 2199€ a year — the page prints the monthly equivalents as “16.58”, “41.58”, “91.58” and “183.25” — with quotas restated per year: 25, 50, 100 and 250 CMD signatures, and certificate-less signatures at 100, 250 and then “ilimitadas” on Growth and Enterprise. Prices exclude tax: “Os preços apresentados não incluem IVA.”
• DigitalSign. A certificate authority rather than a subscription platform, and its own footer describes it as “uma multinacional, com sede em Portugal” and “um Qualified Trust Service Provider, credenciado no âmbito do Regulamento Europeu eIDAS”. Its shop prices the certificate against the device that holds it: on the qualified certificate pages, Pack SmartCard is 140,00€ + IVA and Pack USB is 160,00€ + IVA; the cloud profile is Pack HSMCLOUD at 159,00€ + IVA. Each pack is a three-year certificate and includes “100 selos temporais”, the “1ª anuidade”, the cryptographic device and the software. Two lines on the same page decide the real cost: “As anuidades subsequentes (opcionais) terão um valor de 99€ +IVA”, immediately followed by “O não pagamento das anuidades originará a revogação automática do certificado” — optional in one sentence, mandatory in the next — plus “Para manter a sua licença de uso ativa, terá associado o custo anual de 25€ + IVA.” Signing software is a separate purchase: DS Sign&Go at 76,00€ + IVA bought alongside a certificate, or 115,00€ + IVA on its own, currently shown at 92,00€ + IVA under a “Campanha de Lançamento - 20% desconto”. Issuance is not instant: original documents go by post or in person, and “A documentação será verificada num prazo máximo de 2 (dois) dias úteis após a sua receção e confirmação de pagamento.”
• SIBS Multicert. The other Portuguese certificate house, and the one that publishes least. There is no pricing page anywhere in its published pt_sitemap.xml; prices live in the online store, which answers a short questionnaire with cards. For an individual: “Certificado Individual Particular — A partir de 115,00 €” and “Certificado de Qualidade Particular — A partir de 115,00 €”. The first of those carries a line that says who Multicert thinks buys it: “Exemplo: Pessoas sem Cartão de Cidadão Português”. For a business: “Certificado de Representação — A partir de 132,20 €”, with “Certificado de Fatura Eletrónica” and “Certificado de Selo Eletrónico” both “A partir de 145,00 €”. Every one of those is an “a partir de”, and pressing Personalizar Certificado opens a form headed “Preencha os seus dados para simular o preço do seu certificado” asking for name, surname, telephone and email — so the exact number costs you a contact record. One detail worth knowing before you pay for anything: its free Multicert ID app “permite assinar documentos PDF com certificados qualificados remotos através do seu telemóvel” and lets you “criar um certificado pessoal gratuito para começar a utilizar”. The page does not say that the free personal certificate is a qualified one, so do not assume it is.

What the Portuguese market actually meters

In Brazil the unit is the document; in Spain it is a mixture of seats and sends. In Portugal it is the signature, by type — and, on the certificate side, the year.

AssinaJá’s plans count CMD signatures separately from “assinaturas sem certificado”, which is the distinction that matters, because only the first is qualified. Its own pricing FAQ says the annual plan “custa menos por mês do que o mensal e vem com quotas substancialmente maiores.” The first half is true everywhere; the second depends on the plan, once you compare like for like. Taking the monthly plan’s quota as renewing each month — which is what the page implies when it singles out the Free plan as the one whose limits “não se renovam” — a year of each looks like this:

• Core. Monthly costs 228€ a year and yields 36 CMD signatures and 120 certificate-less ones. Annual costs 199€ and yields 25 and 100. Cheaper, and smaller.
• Launch. Monthly is 588€ for 60 CMD and 300 certificate-less. Annual is 499€ for 50 and 250. Same shape.
• Growth. Monthly is 1,188€ for 120 CMD and 1,200 certificate-less. Annual is 1,099€ for 100 CMD, but certificate-less signatures become unlimited. Which way that falls depends entirely on your mix.
• Enterprise. Monthly is 2,388€ for 240 CMD. Annual is 2,199€ for 250 CMD plus unlimited certificate-less. Here the annual plan is cheaper and larger on both counts.

So the annual switch is unambiguously right at the top of the range and is a trade at the bottom of it. Count your qualified signatures before choosing, not your documents.

On the certificate side the meter is time. A DigitalSign cloud certificate is 159€ for year one, then 99€ for each of years two and three, plus 25€ a year to keep the licence current — roughly 432€ plus IVA across the three years the certificate is valid for, for one person. Multicert publishes a floor rather than a price. Neither model gets cheaper because you send more documents, and neither gets more expensive either.

What the law says, in its own words

Portugal runs on eIDAS, executed domestically by Decreto-Lei n.º 12/2021, de 9 de fevereiro. Its article 3.º, Forma e força probatória, is the provision every argument in this market eventually reaches:

1 - O documento eletrónico satisfaz o requisito legal de forma escrita quando o seu conteúdo seja suscetível de representação como declaração escrita.

2 - A aposição de uma assinatura eletrónica qualificada a um documento eletrónico equivale à assinatura autógrafa dos documentos com forma escrita sobre suporte de papel e cria a presunção de que: a) A pessoa que apôs a assinatura eletrónica qualificada é o titular desta ou é representante, com poderes bastantes, da pessoa coletiva em causa; b) A assinatura eletrónica qualificada foi aposta com a intenção de assinar o documento eletrónico; c) O documento eletrónico não sofreu alteração desde que lhe foi aposta a assinatura eletrónica qualificada.

Two later numbers of the same article decide what happens when the signature is not qualified, and they are the ones that usually get left out of a summary:

9 - O disposto nos números anteriores não obsta à utilização de outro meio de identificação eletrónica, de comprovação da integridade, de correção da origem dos dados ou ainda de atestação temporal de documentos eletrónicos, incluindo outras modalidades de assinatura eletrónica, desde que tal meio seja adotado pelas partes ao abrigo de válida convenção sobre prova ou seja aceite pela pessoa a quem for oposto o documento.

10 - Salvo disposição especial, o valor probatório dos documentos eletrónicos não associados a serviços de confiança qualificados é apreciado nos termos gerais do direito.

Read together: a qualified signature buys you presumptions; anything else is perfectly usable and is weighed under the ordinary law of evidence — and the statute expressly names the lever that strengthens it, a convenção sobre prova, an agreement between the parties on what will count as proof. If you sign commercial contracts at simple or advanced level in Portugal, a clause in which both sides accept the platform’s record as evidence of authorship and integrity is the cheapest risk reduction available to you, and it is the statute’s own suggestion rather than ours.

It is worth being precise about what the qualified tier gets, because vendor pages are not always. Article 3.º, n.º 5 sends a qualified signature to article 376.º of the Civil Code, whose first paragraph reads: “O documento particular cuja autoria seja reconhecida nos termos dos artigos antecedentes faz prova plena quanto às declarações atribuídas ao seu autor, sem prejuízo da arguição e prova da falsidade do documento.” That is the force of a signed private document. It is not article 375.º, Reconhecimento notarial, which is a different article about signatures recognised in person under notarial law. A qualified signature is not a notarised one, and pages that describe it that way — AssinaJá’s CMD explainer says a CMD signature has “a mesma força legal que uma assinatura reconhecida presencialmente por notário” — are overstating a provision that is already strong enough.

The same explainer cites the wrong decree: it tells readers that “O enquadramento nacional consta do Decreto-Lei n.º 290-D/99, na redação dada pelo Decreto-Lei n.º 88/2009”. Article 36.º of Decreto-Lei n.º 12/2021 is headed Norma revogatória and begins “São revogados: a) O Decreto-Lei n.º 290-D/99, de 2 de agosto, na sua redação atual”. The outcome the page describes is broadly right; the authority it cites was repealed in 2021. Check the legal claims on any vendor page, including this one, against the Diário da República.

Two more provisions settle questions people ask constantly:

• Real estate is out of reach of any e-signature. Article 875.º of the Civil Code: “Sem prejuízo do disposto em lei especial, o contrato de compra e venda de bens imóveis só é válido se for celebrado por escritura pública ou por documento particular autenticado.” Qualified or not, a signature alone does not satisfy that form.
• Nobody’s qualified status is yours to take on trust. Article 6.º of the same decree-law makes the Gabinete Nacional de Segurança the supervisory authority, “competindo-lhe, ainda, elaborar e gerir as listas de confiança nos termos previstos no artigo 22.º do Regulamento”. The European Commission’s EU Trusted List browser publishes those lists, per country and per service. A company can be qualified for one service and not another, so check the service you need. The three eIDAS tiers, and which one a normal commercial contract needs, are set out in eIDAS explained: SES, AdES and QES.

What to check before you sign anything

1. Whether your signers already hold an activated CMD. Nine and a half million sign-ups is not nine and a half million people who have switched the signature function on, and how they activated the key decides whether they can switch it on from home or must visit a counter.
2. Whether the signature must bind a company. A CMD cannot; it is personal by design. That question alone moves you from a free state credential to a paid certificate of representation or an electronic seal, and it is the single most expensive fork on this page.
3. Which meter you are actually buying. AssinaJá counts qualified CMD signatures separately from certificate-less ones, plus users, storage and SMS. The certificate houses count years. Nobody here counts documents, which is the unit most international comparisons assume.
4. Monthly against annual, on your own numbers. As shown above, AssinaJá’s annual plans are cheaper per year and, at Core and Launch, smaller per year. Do the multiplication before you take the discount.
5. The three-year cost of a certificate, not the sticker. Annuities at 99€ and a 25€ licence turn a 159€ purchase into something closer to 432€ plus IVA over the life of the certificate, and the annuity described as optional is the one whose non-payment revokes it.
6. Tax, and what “a partir de” hides. Every Portuguese price on this page is quoted excluding IVA, and Multicert’s are floors that resolve only after you hand over contact details. Compare like for like before concluding anyone is cheaper.

Where Signatura fits

Signatura is a per-seat platform: one plan, unlimited documents, no send meter, and no charge for the people who sign. For a Portuguese buyer our pricing page shows euros — from 21€ per seat per month on the annual plan, 28€ billed monthly, with volume discounts as the team grows, on our pricing page. Every completed document carries a full audit trail and a SHA-256 tamper-evident seal that can be re-verified at any time; the details are on our security page.

Where Signatura is not the right answer, stated plainly, because in this market it matters more than anywhere else we sell: we produce Simple Electronic Signatures. We are not a qualified trust service provider, we do not issue certificates, and we do not integrate the Chave Móvel Digital. If what you need is a qualified signature, Portugal gives most individuals one for nothing and the two certificate houses above sell the rest. We would rather say that than sell you something we do not make.

What we are for is the other half of the problem — sending documents to counterparties who may be anywhere, tracking what has been signed, and paying a predictable price per seat rather than per signature. If your contracts are ordinary commercial agreements, if your counterparties are outside Portugal as often as inside it, and if your volume is higher than your headcount, that is the trade this product makes. Pair it with the convenção sobre prova clause the statute itself points at, and you have a defensible file at a forecastable cost. The same comparison in the two neighbouring markets is in e-signature in Spain and e-signature in Brazil. In Mexico every platform on the shortlist publishes a price, but each meters the document a different way: e-signature in Mexico.

Frequently asked questions

Is an electronic signature legally valid in Portugal?

Yes, and at two different strengths. A qualified electronic signature — a CMD signature or one made with a qualified certificate — is equated by article 3.º, n.º 2 of Decreto-Lei n.º 12/2021 to a handwritten signature and creates presumptions of authorship, intent and integrity, giving the document the force of a signed private document under article 376.º of the Civil Code. Any other electronic signature is admissible and is assessed “nos termos gerais do direito” under n.º 10 of the same article, and n.º 9 expressly allows the parties to agree in advance, by a convenção sobre prova, that it will be accepted between them. The general position across jurisdictions is in are electronic signatures legally binding?

How much does it cost to sign with the Chave Móvel Digital?

The state publishes no price for activating a CMD or for signing with one, and AssinaJá’s guide to it states that “A adesão é gratuita”. What a CMD will not do is sign on behalf of a company — the state’s FAQ says it is “só está disponível para pessoas individuais” — or manage a signing process: sending to counterparties, tracking status, templates and bulk sending are what the commercial platforms charge for.

What does e-signature software cost in Portugal?

AssinaJá publishes five plans: Free, then Core at 19€ a month, Launch at 49€, Growth at 99€ and Enterprise at 199€, or 199€, 499€, 1,099€ and 2,199€ a year, all excluding IVA, with CMD signatures metered separately from certificate-less ones. A qualified certificate is bought rather than subscribed: DigitalSign lists 140,00€ + IVA for a smartcard pack, 160,00€ for USB and 159,00€ for its cloud profile, each covering three years with subsequent annuities at 99€ + IVA, and SIBS Multicert’s store opens at 115,00 € for a personal certificate, quoting exactly only after you fill in a contact form.

Do I need a qualified electronic signature in Portugal?

Usually not, but the answer is unusually cheap to act on here, because most individuals already hold the credential. Ordinary commercial contracts do not require a qualified signature; certain acts do, and some forms are beyond electronic signature altogether — article 875.º of the Civil Code still requires escritura pública or a documento particular autenticado to sell immovable property. Decide the level first, because in Portugal it decides whether your answer is free, a subscription or a certificate purchase.

How do I verify that a provider is really a qualified trust service provider?

Not from the provider’s own page, and not from ours. Under article 6.º of Decreto-Lei n.º 12/2021 the Gabinete Nacional de Segurança supervises trust services in Portugal and maintains the national trusted lists under article 22.º of the eIDAS Regulation; the European Commission publishes them in the EU Trusted List browser, service by service. Check the specific service you intend to buy rather than the company name.

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Sources: Autenticação.gov — Estatísticas — “Número Total de Adesões” of 9.743.199 and “Número Total de Autenticações” of 140.783.983. Autenticação.gov — assinatura com CMD and assinatura digital — the “mesma validade de uma assinatura à mão” and “certificada pelo Regulamento 910/2014” lines, “O Estado português garante a certificação…”, browser signing “dispensando a instalação de software”, and the note that some PDF readers may not recognise the signature although it is valid. Perguntas frequentes sobre Chave Móvel Digital — “só está disponível para pessoas individuais”, and the cancellation of the signature when the Cartão de Cidadão is cancelled. Ativar a assinatura digital da CMD — activation via Finanças or TV box leaving only the counter route; and Software para assinar com CMD for the list of certified third-party applications. AssinaJá preços — the “Atualizado em 5 de agosto de 2026” label, the five monthly plans at 0€ / 19€ / 49€ / 99€ / 199€ with their quotas, the annual plans at 199€ / 499€ / 1099€ / 2199€ with monthly equivalents “16.58”, “41.58”, “91.58” and “183.25” and their restated quotas, the Free plan footnote “Estes limites são atribuídos uma única vez e não se renovam”, “O plano anual custa menos por mês do que o mensal e vem com quotas substancialmente maiores”, and “Os preços apresentados não incluem IVA.” The served HTML shows only the monthly view; the annual view was read from the page’s own published data. AssinaJá — sobre and its Chave Móvel Digital guide — “É competente a assinar, mas não gere circuitos…”, “A adesão é gratuita”, the notary comparison, and the citation of Decreto-Lei n.º 290-D/99. DigitalSign — “Pack SmartCard 140,00€ + IVA”, “Pack USB 160,00€ + IVA”, “Serviço Prioritário 65,00€ + IVA”, “DS Sign and Go 76,00€ + IVA”, the three-year validity, “100 selos temporais”, “1ª anuidade”, “As anuidades subsequentes (opcionais) terão um valor de 99€ +IVA”, “O não pagamento das anuidades originará a revogação automática do certificado”, the 25€ + IVA licence, and the two-working-day documentation check; cloud profile — “Pack HSMCLOUD 159,00€ + IVA”; DS Sign and Go — “Preço: 115,00€ + IVA”, “Novo preço: 92,00€ + IVA”; and the site footer’s QTSP self-description. SIBS Multicert loja online — “Certificado Individual Particular” and “Certificado de Qualidade Particular” both “A partir de 115,00 €”, “Certificado de Representação — A partir de 132,20 €”, “Certificado de Fatura Eletrónica” and “Certificado de Selo Eletrónico” both “A partir de 145,00 €”, and the “Preencha os seus dados para simular o preço do seu certificado” form; read in a browser, because the store is a client-rendered application. Absence of a pricing page confirmed against multicert.com/pt_sitemap.xml. App Multicert ID — signing PDFs “com certificados qualificados remotos” and “criar um certificado pessoal gratuito”. Decreto-Lei n.º 12/2021 — article 3.º in the consolidated text, article 6.º on the GNS and the trusted lists, and article 36.º repealing Decreto-Lei n.º 290-D/99; Código Civil — articles 375.º, 376.º and 875.º. Qualified status should be confirmed against the EU Trusted List browser rather than any vendor’s description of itself. Prices and allowances change without notice — check each vendor’s live page before relying on a number.