The Developer's Guide to the eSignly eSignature API
Build seamless, secure, and compliant document signing workflows directly into your application.
Go from API key to your first signed document in minutes.
Stop wasting months building and maintaining complex, compliant signing infrastructure. With eSignly's developer-first REST API, you can focus on your core product while we handle the heavy lifting of document security, legal validity, and scalability. Integrate powerful eSignature capabilities that your users will love and your legal team will approve.
Trusted by developers at forward-thinking companies worldwide
Why Build with the eSignly API?
Developer-First Experience
Get up and running in minutes with our clean REST API, comprehensive documentation, interactive API explorer, and SDKs for your favorite languages.
Ironclad Security
Protect your data with enterprise-grade security. We are SOC 2, ISO 27001, HIPAA, and GDPR compliant, with all data encrypted in transit and at rest.
Global Legal Compliance
Our signatures are legally binding under the ESIGN Act, UETA, and international regulations. Every document comes with a complete, court-admissible audit trail.
Scalable & Reliable Infrastructure
Built on robust cloud infrastructure to handle millions of API calls. We offer up to a 100% uptime SLA, ensuring your workflows are never interrupted.
Transparent & Predictable Pricing
Start for free and scale as you grow. Our volume-based pricing is straightforward with no hidden fees, making it easy to predict costs and manage your budget.
Powerful, Flexible Features
From embedded signing and templates to bulk sending and webhooks, our API provides the powerful features you need to build any document workflow imaginable.
Seamless White-Labeling
Embed the signing experience directly into your app or website. Customize the UI with your own branding for a completely seamless user journey.
Comprehensive Audit Trails
Every action is tracked and timestamped, from document creation to final signature. Access a detailed audit log via the API for ultimate traceability and compliance.
Dedicated Developer Support
Our expert support team is here to help you succeed. Get timely, technical assistance to resolve any integration challenges and optimize your implementation.
Core API Features
RESTful Architecture
Our API follows standard REST principles with predictable, resource-oriented URLs and uses standard HTTP response codes, authentication, and verbs, making it easy to integrate with any stack.
- Intuitive endpoints for documents, signers, and templates.
- JSON-based requests and responses for easy parsing.
- Clear and consistent error handling.
Embedded Signing
Provide a seamless signing experience by embedding the entire workflow within your application or website using an iframe. Users never have to leave your platform.
- Generate a unique, single-use signing URL for each recipient.
- Full control over the user journey and post-signing redirects.
- Enhances user trust and improves completion rates.
Templates API
Programmatically manage and use templates to streamline document creation. Define roles, fields, and signing orders once, then reuse them for thousands of documents.
- Create, list, and manage templates via API endpoints.
- Pre-fill data into template fields for dynamic document generation.
- Drastically reduces redundant code and speeds up document setup.
Bulk Sending
Send the same document to hundreds or thousands of recipients with a single API call. Ideal for NDAs, policy updates, and consent forms.
- Upload a list of recipients and let our system handle the distribution.
- Track the status of each individual signature request.
- Automates mass-signing workflows, saving significant time.
Webhooks (Real-time Notifications)
Stay updated on the status of your documents in real-time. Configure webhooks to receive instant notifications for events like 'document viewed', 'signed', or 'completed'.
- Eliminates the need for constant API polling.
- Trigger downstream actions in your application automatically.
- Ensures your system is always in sync with the document lifecycle.
SDKs for Popular Languages
Accelerate your integration with our official Software Development Kits (SDKs). We provide helper libraries for popular languages to handle authentication, requests, and responses.
- Available for Python, Node.js, PHP, Java, and .NET.
- Simplifies API interactions and reduces boilerplate code.
- Maintained and updated with the latest API features.
Audit Trail API
Programmatically access the detailed, court-admissible audit trail for any completed document. Retrieve a full history of events, including IP addresses, timestamps, and actions.
- Integrate compliance data directly into your own systems.
- Automate document archiving and record-keeping.
- Provides irrefutable proof of the signing process.
Custom Branding (White-Labeling)
Customize the look and feel of the signing experience to match your brand. Control logos, colors, and email templates for a fully integrated feel.
- Maintain brand consistency throughout the user journey.
- API endpoints to manage branding assets.
- Builds user trust and reinforces your brand identity.
Sandbox Environment
Develop and test your integration with confidence in our full-featured sandbox environment. Mimics the production environment without affecting live data or incurring costs.
- Free access with every developer account.
- Test all API endpoints and features thoroughly before going live.
- Ensures a smooth and error-free deployment.
Get Started in 3 Simple Steps
Get Your API Key
Sign up for a free developer account to get instant access to your sandbox and production API keys.
Install SDK & Code
Choose your preferred language, install our lightweight SDK, and use our code examples to build your first request.
Send & Sign
Send your first signature request. Embed the signing session or send an email link, and get notified upon completion.
Powerful Use Cases for Any Industry
SaaS Platforms
Automate user agreements, service contracts, and subscription sign-ups directly within your application onboarding flow.
FinTech & Banking
Securely execute loan applications, account openings, and compliance documents with legally binding signatures.
HR Technology
Streamline hiring with automated offer letters, NDAs, and onboarding paperwork for new employees.
HealthTech
Ensure HIPAA compliance by capturing patient consent forms, intake documents, and treatment plans securely.
LegalTech
Power your platform with embedded client engagement letters, retainer agreements, and legal filings.
Real Estate
Accelerate deals by automating lease agreements, purchase offers, and disclosure forms for agents and clients.
From Our Customers: Real-World Success
HR Tech Platform Automates Offer Letters
Client Overview
An innovative HR technology company provides a comprehensive platform for talent acquisition and employee onboarding. Their goal was to create a seamless, fully digital experience for both recruiters and new hires, eliminating the need for manual paperwork.
The Challenge
Their existing process required recruiters to download offer letter templates, manually fill them out, and send them via email for printing and signing. This was slow, error-prone, and provided a poor candidate experience.
"The eSignly API was a game-changer. We integrated a fully branded signing experience in less than two weeks. Our time-to-hire has dropped, and candidates love the modern, easy process."
Our Solution & Outcomes
Using the eSignly API, they embedded the eSignature workflow directly into their platform. Recruiters can now generate and send offer letters with a single click, and candidates can sign on any device in seconds.
Real Estate SaaS Streamlines Lease Agreements
Client Overview
A leading SaaS provider for property management firms needed to digitize their leasing process. Their platform helps landlords manage properties, and a key friction point was the slow, paper-based process of executing lease agreements.
The Challenge
Property managers were juggling PDFs, email attachments, and in-person meetings to get leases signed. This delayed move-in dates, created compliance risks, and frustrated both landlords and tenants.
"We needed an API that was reliable, secure, and easy for our developers to work with. eSignly delivered on all fronts. Our clients can now close leases in hours, not days."
Our Solution & Outcomes
LeaseWell integrated eSignly's embedded signing API. Now, property managers can auto-populate lease agreements with tenant and property data and initiate the signing process directly from their dashboard. Tenants receive a link to review and sign the lease on their phone or computer.
FinTech App Secures Loan Applications
Client Overview
A fast-growing FinTech startup offers an online platform for personal and small business loans. Security, compliance, and speed are critical to their business model and for building trust with their users.
The Challenge
Their loan application process required a legally binding signature, but their initial solution was clunky and didn't provide the robust audit trails needed for financial regulations. This created a bottleneck in their funding pipeline.
"For a FinTech, security and compliance are non-negotiable. The eSignly API provided the bank-grade security and detailed audit logs we needed to satisfy our regulators and give our customers peace of mind."
Our Solution & Outcomes
They integrated the eSignly API to handle the final signature on all loan agreements. Using webhooks, their system is instantly notified when a loan document is signed, allowing them to trigger the fund disbursement process automatically.
Developer Resources
Full API Documentation
Explore our comprehensive docs with guides, tutorials, and detailed endpoint references.
SDKs on GitHub
Grab our official SDKs for Python, Node.js, PHP, and more to get started quickly.
API Status Page
Check the real-time status of our API and subscribe to updates for service notifications.
Contact Support
Have a question? Our developer support team is ready to help you with your integration.
What Developers Are Saying
"The documentation is some of the best I've ever worked with. Clear, concise, with actual useful code examples. We had a proof-of-concept running in an afternoon."
"We switched to eSignly for the embedded signing feature. The user experience is incredibly smooth, and our completion rates have gone up significantly. It just works."
"As a startup in a regulated industry, compliance was our biggest concern. eSignly's security certifications and detailed audit trails gave our legal team the confidence to move forward."
"The webhook system is fantastic. We've automated our entire post-signature workflow, from updating our CRM to notifying the team on Slack. It's a huge time-saver."
"The sandbox environment is a perfect replica of production. We were able to test every edge case imaginable before writing a single line of production code. Made for a flawless launch."
"We needed to send thousands of documents at once for a compliance update. The bulk sending endpoint handled it without a hitch. What would have taken days of manual work was done in minutes."
Transparent Pricing for Every Scale
Start building for free in our sandbox. When you're ready to go live, choose a plan that fits your volume. No surprises, no hidden fees.
| Feature | Free | Professional | Business | Enterprise |
|---|---|---|---|---|
| API Requests / month | 100 (Sandbox) | Starts at 500 | Starts at 2,000 | Custom Volume |
| Embedded Signing | ||||
| Templates | ||||
| Custom Branding | ||||
| Dedicated Support |
Frequently Asked Questions
Yes. Signatures collected via the eSignly API are legally binding under the U.S. ESIGN Act, UETA, and other international laws. We provide a comprehensive, court-admissible audit trail for every transaction.
Our REST API is language-agnostic. We also provide official SDKs for popular languages including Python, Node.js, PHP, Java, and .NET to accelerate your development process.
Absolutely. You can sign up for a free developer account which gives you full access to our sandbox environment and a limited number of live API calls to get you started.
We offer tiered pricing based on the volume of signature requests. Our plans are designed to scale with your business, from startups to enterprise-level usage. You can find detailed information on our API pricing page.
Yes, our API supports extensive white-labeling. You can embed the signing session directly into your application and customize the branding, colors, and logos to create a seamless user experience.
Security is our top priority. We are compliant with SOC 2, HIPAA, GDPR, and ISO 27001. All data is encrypted in transit and at rest, and we provide robust features like multi-factor authentication and detailed audit trails.
Enterprise-Grade Security & Compliance
Ready to Start Building?
Integrate powerful, secure, and compliant eSignatures into your application in minutes. Get your free API key and start exploring our sandbox environment today.
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