8 Best eSignature APIs in 2023 [TOP Recommendations]

Read, review, and compare the best eSignature APIs solution that enables any document to be signed electronically or digitally:

What is eSignature?

eSignature, in simple words, is an electronic signature for the documents required to be signed.

Think of a scenario where a sales deed or contract note or even a shopping bill would usually require a signature in the physical world. But how would you handle that situation in a digital ecosystem? It would be tedious to have those physically signed and then scanned and then sent to the appropriate parties.

Broadly, as documents have become digitized, so have the signatures. Modern signatures or coined eSignatures do not rely on a pen-paper mechanism but cryptographic private-public keys and can be deemed as secure and legit as physically signed documents.

E-signatures can take different forms, like having an individual’s name typed out, an uploaded image of a person’s cursive signature, or an actual image of the signature representing the person’s identity.

eSignature APIs – A Complete Review

Best ESignature APIs (1)

Electronic Signature vs Digital Signature

Digital and electronic signatures might sound synonymous but are not the same. All digital signatures are types of electronic signatures, but not vice versa.

Electronic signature provides a way for someone to attach their name to a document, while digital signatures are a step further and include validation in the form of a certificate before an individual can digitally sign a document.

How do APIs Perform eSign

eSignature APIs are a REST-based web service that can allow the subscriber to request signatures, get status updates and download signed documents.

To use an electronic signature API, the developer needs to have an API key or an authorization token and then can call GET/POST methods for signing the document, encrypting it, etc.

Pros and Cons of using eSignature APIs

While there are many good reasons to move to digital signatures or eSignature APIs it’s important to understand or at least know what would be not so good about these.


  • Easy to integrate and use.
  • Less prone to human errors.
  • Improves accuracy and reduces the scope for fraud and tampering.
  • Saves a lot of logistics costs as against Physical document signature.
  • Reduce friction and enhance the customer experience.


  • Since the documents can be confidential, storing them digitally on the cloud still poses a security risk of information leaks.
  • Defects in code or APIs – or if the credentials are leaked, could lead to the unauthorized use of digital signatures.
  • Lock-in with proprietary software or vendors will be difficult to migrate in the future.

Market Trends: According to Fortune Business Insights, the global digital signature market is projected to grow at a CAGR rate of 36.1% from 2022-2029. It’s projected to grow from $4.05 billion today to $35.03 billion in 2029.

global digital signature market

Covid 19 Pandemic has fuelled the adoption of digital signatures worldwide with a growing number of online and remote work cultures which is leading to industries and companies relying on digital signatures for their day-to-day needs.

Banking and Finance is one of the biggest sectors and users of digital signatures and has quickly adopted using these which helps in reducing fraudulent documents and streamlines various processes like account opening, digital KYC, etc.

Expert Advice: For choosing the best eSignature APIs, the below factors should be taken into consideration.

For choosing a good eSign API solution, consider understanding some basic features like below:

  • Ability to send/configure recipients for a document to be signed.
  • Ability to construct/create documents/contracts, create fillable forms, etc for preparing documents.
  • Integration with standard apps and document formats – like MS Dynamics, Google Docs, and Dropbox. Since most of the customers are already using these platforms and out-of-the-box integration with these would result in less friction for customers and easy integration with existing solutions.
  • Ability to configure custom workflows, role-based signatures, etc.
  • Bulk sending to multiple recipients.
  • Should have pricing plans that could cater to volume-based usage.

FAQs on API Signature

Q #1) What is E-Signature Software?

Answer: eSignature APIs or commonly called eSign API is a Software-based solution that enables any document/contract to be signed electronically or digitally. It’s similar to signing any document, but not with a pen-paper model in the physical world, but through cryptographic keys that identify and authorize a sender and recipient.

Q #2) What are the common features of E-Signature Software?

Answer: Some of the common features of eSignature API software are:

  • Provides a graphical interface to send documents and set up documents/contracts through a drag-and-drop interface.
  • Ability to configure conditional workflow for having a document signed by multiple recipients.
  • Additionally integrations with standard applications like Microsoft Dynamics, and Google docs – so that documents hosted by these platforms could be sent for signing.

Q #3) What is API in eSignature?

Answer: The eSignature solutions can provide services with the help of a GUI interface or an eSign API which is nothing but a REST-based API providing different endpoints like GET/POST and exposing functionality to specify recipients for a doc, sent it to the recipients, get the signed document, compute cryptographic hash, etc.

Q #4) Does DocuSign have an open API?

Answer: DocuSign offers an API-based eSign solution called DocuSign eSignature API. The documentation can be accessed here.

In order to use this API, you would need to sign up with DocuSign and obtain an API key that serves as an authentication and authorization mechanism, and then you could use this API to build custom workflows, send documents for getting signatures, get audit trails, etc.

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List of the Best eSignature APIs

Recommended list of eSign API solutions:

  1. signNow (Recommended)
  2. DocuSIgn
  3. Adobe Acrobat Pro
  4. PandaDoc
  5. Esignatures.io
  6. HelloSign
  7. Preview for MacOS
  8. signWell

Comparison Chart of Top eSign API Solutions

esign APIsTop FeaturesBest ForSupported PlatformsPricing
signNowIntuitive interface, Powerful eSign API with high success rateBest for seamless eSignature experience anytime/anywhere.Supports 20+ out-of-the-box integrations with popular platforms like - Microsoft Teams, MS Office, Google Docs, Salesforce, etc.• Professional Plan: $146/month
• Enterprise Plan: Contact Sales
DocuSignExtensive file support, Configure signing workflowseSignature support on practically any device/platform.400+ integrations including - Slack, Workday, Google Docs, and Dropbox• Starts from $10/month for individual plans.
• Premium plans start at $20/month
Adobe Acrobat ProPower of Adobe Acrobat PDF, Has done 8 billion+ signaturesExtensive support and integration with Adobe products as well as for applications that are using Microsoft-based platforms tools.Smart integrations with major platforms like Microsoft, Workday, ServiceNow, MasterCard, etc.• Individual plans at $19.99/month
• Team plans start at $23.99/month
PandaDocDrag and drop editing of documents, 750+ ready-to-use templatesGreat content library and templates for creating documents that need to be eSigned.Business plans support CRM and Zapier Integration
Enterprise plans further support Salesforce Integrations
• Offers Free trial and limited features free for life account.
• Business and enterprise plans start at $49/month
eSignatures.ioSMS integration,
Workflow automation for multiple signers
Fully managed contracts with the API, and great integration with devices with small screen sizesBoth business and Standard plans come with API integration and Zapier support which can integrate with platforms like Salesforce, Dropbox, etc.• Standard: $0.49/sent contract
• Enterprise: $4k/month
HelloSignEasy integration, Customised templates and brandingAs part of Dropbox family, allows to securely sign, store and organize contracts in a single place.Integrations with Salesforce, Dropbox, Google docs, Slack, and Microsoft Dynamics 365 are supported.• Test mode is free for testing out in the sandbox.
• Essentials and Standard plans come at $75/month and $250/month respectively.
signWellCompliant with US and International eSignature laws, instant signing and document workflowsBest for instant signing with legally valid electronic signatures.Standard integration with Zapier API• Offers free trial.
• Premium and Business plans start at $8/month

Detailed Review:

#1) signNow (Recommended)

Best for a seamless eSignature experience anytime, anywhere, and on any device.


signNow can help you with eSignatures that can scale with your workflow. It can be used to get the documents/contracts eSigned and accepted as legally binding contracts. signNow can be used to provide a Seamless experience anytime, anywhere, and on any device.


  • Quick and easy intuitive interface to upload, eSign, or send the document to multiple recipients for signature.
  • API is powerful with a high success rate and can be used to provide brandable eSignature solutions.
  • Powerful integrations with web, CRM, and any custom app.
  • Create custom conditional workflows and configure automatic routing depending on the assigned role to the recipients.
  • Provides reusable templates for document creation which could be further customized.


  • One of the best solutions for embedded signing.
  • Simple to implement.


  • The templates are not customizable.

Verdict: signNow eSign API solution is simple to follow and implement and could be integrated within hours. Offers unique capabilities for embedded signing and offers powerful integration with common CRM tools which makes it a good fit for lots of customers.


  • The API Documentation can be accessed here.


  • Offers a free trial for 250 Signature Invites
  • Professional Plan: $146/month
  • Enterprise Plan: Contact Sales
  • API includes a free sandbox and free trial.

#2) DocuSign

Best for eSign support practically on any device and platform.


Developed by DocuSign supports easy integration of eSignature into the documents and allows the API users to request signatures for the documents, download documents as well as embed the interface into applications.

DocuSign empowers more than 250,000 companies and more than 100 million users globally.

It provides one of the most robust eSignature transaction management that includes electronic forms, integration as well as conditional workflows.


  • DocuSign processes millions of documents daily.
  • Offers extensive file type support – like MS Word, Excel, Powerpoint, and PDF formats.
  • Easy integration with other applications to prepopulate forms which saves the hassle and helps to reduce manual errors. Offers field validation capabilities to automate business logic.
  • DocuSign enables you to specify a signing workflow – i.e you can have a document that requires multiple signatures similar to an approval workflow.
  • Features like bulk send – allowing to send unique copies of documents to multiple recipients that need to sign the same document.
  • Multiple levels of authentication for signers to prove their identity before being able to access the documents they are going to sign.

How to request a signature with DocuSign:

In order to request a signature by email using the DocuSign Integration, you can follow the below process:

Step #1: Obtain an OAuth token: This would require you to sign up with DocuSign and get an API key or integration key. You would then need to use this API key to call the DocuSign authentication service which would return an OAuth token

Step #2: Create envelope definition: This essentially creates a template for the signable document in HTML. You would also need to define the documents’ signer, recipient data, and routing order.

Step #3: Create and send the envelope: Use the envelope created in Step #2 and add the OAuth token obtained in step #1 to the request header. When the envelope is sent the documents will be delivered to the specified email addresses of the recipients, and API will return the ID and status of the envelope sent.


  • Ease of use.
  • DocuSign is a trusted name and is highly secure.
  • Multiple integrations available


  • Integration with ServiceNow is a little challenging.
  • Pricey in comparison to other solutions.

Verdict: DocuSign is a trusted brand name for eSignature APIs and is used by more than 500K companies and SDKs in almost all popular languages, it’s a preferred choice for a lot of clients. Additionally, their data centers are spread around the world and have a track record of 99.99% uptime.


  • The documentation for DocuSign eSignature APIs can be accessed here.


  • Starts from $10/month for Individual plans.
  • Also offers Pro, Business and Premium plans to start from $20/month.
  • Offers free trial.

Website: DocuSign

#3) Adobe Acrobat Pro

Best for being a preferred Microsoft solution, it’s best for use by applications closely integrated with Microsoft tools.


A global brand that Fortune 500 companies trust. Supports multiple integrations with key apps including Microsoft 365.

Adobe eSign is a cloud-based eSignature API or a signature API service and is the Microsoft preferred solution it’s the only tool that includes the power of Adobe Acrobat. API access is available for enterprise and developer tier accounts only.


  • Supports document signing anywhere – mobile, laptop, tablet, etc. with no third-party plugins or software required to be installed to sign a document.
  • Track the document signatures with real-time visibility for every document and configure and customize notifications when the recipients sign the document.
  • Multiple integrations out of the box – like ServiceNow, Salesforce, Microsoft Dynamics, SAP, Workday, etc.
  • Customize signature with documents bearing the custom logo, images, taglines as well as confirmation page that the recipients see after signing the document.
  • Bulk sends the document to multiple recipients.

How to request a signature with Adobe Acrobat Pro:

You can validate the integration with Adobe API by signing up for a free developer account.

Step #1: Create an Adobe ID and log in to that account. Once signed up, you should be able to get access to eSign API

Step #2: Retrieve the auth token using the API Key, and create an Agreement or document using the Rest API document reference.

Step #3: Now the document should be uploaded by sending POST to /transient documents which would return a document ID or reference ID.

Step #4: Now send the document ID along with other details like recipient emails, and workflow info. This would return a reference ID which could be used for tracking in the future.

Step #5: Track and monitor the status of the document that was sent for signing.


  • Since Adobe PDFs are one of the most widely used doc formats, Acrobat Pro is highly compatible with PDF.
  • Supports certificate-based digital signatures.


  • Doesn’t have a lot of integration for mobile devices for eSigning.
  • No changes can be made to the signed documents in case of a re-verification required doc has to be created again.

Verdict: Coming from the house of Adobe offers extensive integration with PDF document formats, but lacks integrations with mobile devices, and doesn’t offer a lot of flexibility for updating the documents/contracts that need to be re-signed.


  • Documentation for Adobe Acrobat eSignature API can be accessed here.


  • Individual Acrobat Pro starts at $19.99/month (when billed annually).
  • Teams license starts at $23.99/month/seat.

Website: Adobe Acrobat Pro

#4) PandaDoc

Best for teams looking for building documents/contracts with a huge set of libraries and pre-defined templates.


With over 40K customers globally Pandadoc is the preferred platform for creating proposals, contracts, and quotes and then using the eSign APIs for getting the appropriate recipients to sign the document.

Using Pandadoc API signature, you can easily automate your workflow and generate documents without any tedious data entry.


  • Use drag-and-drop editing features to build documents, contracts, and quotes with 750+ ready-to-use templates. You can also customize the templates as required.
  • Real-time access to document approvals, signatures, and version tracking.
  • Native CRM integrations help to streamline the entire document workflow.

How to request eSignature with PandaDoc:

In order to test the integration you can get started with a sandbox setup which comes for free.

Step #1: Create your free sandbox account by going to PandaDocs document reference. This would also require you to verify your email address for identification.

Step #2: Once signed up, select a template (or create a new one by customizing an existing one or building one completely from scratch).

Step #3: Generate an API key from the PandaDocs dashboard (through the sandbox account).

Step #4: Receive an OAuth token by sending a request to PandaDocs authentication endpoint.

Step #5: Create a document using PandaDoc template (by following API documentation). After this – the document can be sent via email and recipients could be mentioned as appropriate

Step #6: You can use the monitor on the dashboard to get the status of the document signature.


  • Extensive content and templates library.
  • Real-time co-editing supported.


  • Does not have very good support for formatting documents.

Verdict: PandaDocs is a fast-growing eSign API company and has now about 40K customers. Offers a lot of out-of-the-box templates and very easy-to-integrate API with document and contract formatting and updating capabilities.


  • The eSign API docs can be accessed here.


  • Offers free account with limited features.
  • Business accounts supporting standard integrations start from $49 /month/user.
  • Offers free trial for Business and Enterprise accounts.
  • Built-in legally binding eSignatures.

Website: PandaDoc

#5) eSignatures.io

Best for creating fully managed contracts with the eSign API and extensive integration with small screen size devices.


eSignatures.io is a Truly mobile-friendly eSignature platform and can render a contract on a mobile phone small screen in a highly responsive format.

eSignature.io contracts are legally binding under the 2000 U.S Electronic Signature in Global and National Commerce Act and are an ISO 27001 certified company that is considered as the highest level of global information security and assurance certification.


  • SMS Integration with sending contracts directly to mobiles via SMS.
  • Workflow automation with integration support for apps like Salesforce, Dropbox, etc.
  • The actual signature page/view can be embedded into your website and can be customized as required.
  • Supports features like an Audit trail for tracking the signature audit, and other details like IP address, email addresses, etc.

How to request a signature with esignatures.io:

The esignatures.io API is simple and straightforward to implement.

Step #1: Obtain the API key or secret token by registering with esignatures.io or buying a subscription plan.

Step #2: Call API endpoint POST /api/contract to send a document – Construct the request body per the API documentation which would require you to fill fields like – template_id, title, recipient/signer list, webhook_url, etc.

Step #3: Once the contract is sent, you can query the GET /api/contract to get the status of the contract and if its been received and signed or not.


  • Support for mobile-friendly eSignatures.
  • Pricing is pay-as-you-go – hence no long-term commitments.
  • Simple and extensible API supporting embedded signatures


  • Lack of option between subscribing to pay-as-you-go charges or a monthly or annual subscription.

Verdict: We recommend eSignatures.io if you have a lot of your customer base requiring to sign on mobile devices other than laptops/desktops. It is compliant with most of the eSign compliances like the AU ET Act, ISO 27001 certification, etc.


  • The API documentation can be accessed here.


  • The pricing plans are per sent contract in the Standard plan – It’s $0.49/sent contract.
  • For Enterprise plans there’s a pricing option of either $0.49/sent contract or $4000/month.
  • Both the plans come with API Integration and other features like bulk send, Zapier integration, Embedded signing, etc.

Website: eSignatures.io

#6) HelloSign

Best for being part of the Dropbox family, HelloSign allows you to securely, sign, store, and organize contracts in a single place.

hellosign - eSignature APIs

HelloSign is ranked one of the easiest solutions for implementing eSignature APIs.

With HelloSign API signature, you can secure your documents and embed data encryption, audit trails as wells as adhering to industry standard compliances. HelloSign was acquired by Dropbox and is now named Dropbox Sign.


  • Create a consistent experience for signers and senders by Embedding requesting and signing.
  • Customize and reuse existing templates for making the automatic signature process fast.
  • The Dropbox Sign API offers branding options for creating a highly customized branded experience for your signers.


  • Ease of use.
  • User-friendly and affordable.


  • Customer support is not very prompt.

Verdict: HelloSign is now owned by Dropbox which is a trusted cloud-based storage platform. Hence Dropbox integration comes out of the box which is an important feature. The platform is easy and intuitive and offers legally binding contracts/documents with an audit trail of review and actual document signing.


  • The API documentation can be accessed here.


  • The test mode is free to try without any cost.
  • Offers multiple plans and can be chosen depending on needs
    • The essential plan with $75/month can be used for 50 signature requests per month
    • Standard plans come at $250/month with 100+ signature requests per month and other features like Embedded signing, Signer attachments, etc.
    • For Premium / Enterprise plans, you can contact their sales team.

Website: HelloSign

#7) Preview for MacOS

Best for teams looking for a free-to-use tool for signing documents.

mac-preview - eSignature APIs

Preview for macOS can be used as a general-purpose solution to sign any document (PDF) that needs to be signed. It is not an API-based solution, rather you can use the Preview preferences option and perform document signing. You can capture your signature by recording it on the mouse trackpad and embedding it into the document.


  • Free to use.
  • Good for general-purpose signing.
  • It’s not a legally binding document and hence couldn’t be used to prove the legality or authenticity of the sender.


  • Basic document signing.
  • Free to use.


  • Limited platform support – only MacOS.
  • The signed documents are not legally binding.

Verdict: Preview for macOS is an entry-level document signature solution and is only compatible with documents on Mac OS. Also, it doesn’t have an API and can be just used as a UI interface/tool with limited capabilities.


  • Free to use on Mac-based devices.

Website: Preview for MacOS

#8) SignWell

Best for instant signing with legally valid electronic signatures.

signwell - eSignature APIs

SignWell is one of the best eSignature APIs to create legally binding signatures and allow for a faster and more streamlined document signing process. SignWell is trusted by 61000+ businesses globally.


  • Instant signing with an intuitive interface to configure the document as well as recipients.
  • SignWell is compliant with U.S. and international eSignature laws.
  • Create Document workflows where you can configure multiple conditional workflows and the order in which the document is required to be signed.
  • Great library of templates that could be reused and/or customized as per the needs.
  • Supports cool features like Blank line autodetection which makes setting up documents to be signed and filled out super easy.


  • Clean user interface and easy-to-use API.
  • Multiple reusable templates.


  • Don’t have support for a lot of common integrations like GSuite.
  • Extra charges for sending to multiple recipients.

Verdict: Trusted by more than 61K businesses globally SignWell offers Instant signing with legally valid electronic signatures. With powerful workflows as well as detailed audit trails it makes the monitoring of the contracts or documents to be signed a lot easier and intuitive.


  • SignWell API is in early access and will be soon available. It’s supported to be used with Zapier.


  • Offers free trial and basic plan with 1 sender that can send up to 3 documents a month as a free plan.
  • Personal and Business plan comes at a cost of $8/month

Website: SignWell


In this article, we learned about eSignature APIs or also commonly called as eSign APIs.

The market size of eSignature or digital signature is growing rapidly and has accelerated even since the Covid 19 Pandemic started with companies increasing their digital presence or adapting quickly to digital solutions.

eSign APIs allow a hassle-free way to get the document signed by relevant recipients or parties. These are not only less error-prone but are also fully legit, tamper-proof, and considered as authentic as a normal pen-paper signature would be.

There are numerous apps/solutions providing eSignature APIs as well as visual/graphical interfaces. Some of these eSignature APIs have been discussed in this article and are compared against features and pricing details.

Depending on your requirements you can choose the right eSignature APIs that meet your needs.