Electronic Signature API: What SignSend Does and Does Not Offer

An electronic signature API is a programmatic interface that lets your own software send documents for signature and receive the signed result, without anyone using a dashboard. Instead of a person uploading a file, adding signers, and clicking send, your application makes an HTTP call that does all of it, then listens for a webhook callback to know when the document has been signed.

The practical difference is control and scale. A signing dashboard is for a human sending a handful of documents. An API is for a system that needs to send signing requests as part of a product feature or an automated process, whether that is one a day or thousands a month. Most established e-signature vendors expose this as a REST API with JSON payloads plus webhooks, usually gated behind a developer or enterprise tier and often metered per envelope.

You need an API when signing is embedded in software or a repeatable workflow. Common triggers: you are building a SaaS product and want customers to sign agreements inside your app, you send the same contract or onboarding packet at high volume, you want a CRM or internal tool to fire off an agreement automatically when a deal moves stage, or you need signed files to land in your own database without anyone touching them. If that is you, and you need it now, you should be evaluating vendors that already ship a live API. We are not going to pretend we are one of them.

You do not need an API when a person is comfortable sending documents by hand from a dashboard. If your team sends a few contracts a week and a human is already in the loop, a normal send-for-signature workflow is simpler and cheaper, and you can skip the integration entirely. Many businesses that think they need an API are well served by the standard electronic signature software and never write a line of code. That workflow is live in SignSend today, and it is free to try.

This is what the phrase "e-signature API" normally covers, written out so you can check it against what you need. None of it is part of SignSend, and nobody is building it. It is here to help you rule SignSend in or out in one reading, not to describe something on the way.

• Create a signing request. One authenticated POST that takes the PDF and the list of signers and returns an identifier plus a signing link per signer. In SignSend a person does this from the dashboard.
• Fetch document status. A GET returning each signer’s state so an integration can poll. In SignSend the dashboard shows the same states on screen.
• Download the signed file and audit trail. Endpoints returning the completed PDF and the structured audit record. SignSend already records all of it — timestamps, IP addresses, user agents and the SHA-256 hashes — but you download it yourself.
• Webhooks. An endpoint that receives an event when a document is viewed, signed or completed. SignSend sends none; it emails the parties instead.
• API keys. Per-account keys you issue and revoke. SignSend has no keys because it has no API to key.

To be completely clear about status: the application exposes no public REST endpoints at all. There is no sandbox, no beta key, no documentation and no waiting list, because there is nothing behind any of them.

If your volume is low enough that a person can stay in the loop, the product may already be enough on its own. Today, from the dashboard, you can upload a PDF up to 20MB, add signers by name and email. Each signer is emailed a unique, expiring link and signs in the browser, drawing a signature or typing their name, with no account to create and no seat to pay for. The signature is stamped into the PDF, the signed copy is emailed back to everyone, and it stays downloadable from your dashboard.

Every document also carries an append-only audit trail recording uploaded, sent, viewed, signed, and completed events with actor, IP address, user agent, and timestamp, plus a SHA-256 hash of both the source and the signed file. Signatures collected this way are valid under the federal ESIGN Act and state UETA laws. The free plan covers 3 documents a month with up to 2 signers, which is enough to test the whole flow end to end before you commit to anything. Technical teams sizing this up can also read the electronic signature for IT and software companies page.

Three plans, all live today: Free is $0 for 3 documents a month with up to 2 signers and no credit card, Pro is $12 a month and Business is $29 a month. None of them includes API access, because there is no API to include.

There is no list to join and nothing to sign up for. If programmatic signing is what you came for, take that as a no and use a vendor that ships one. If you want to tell us what you would have built, [email protected] is read by a person — but it buys you nothing and promises you nothing. For a broader look at how flat-rate signing tools compare, see the best e-signature software for small business roundup.