E-signature API · 25¢ per envelope · No monthly fee
Start with 25 free sandbox envelopes, no card. After that it's 25¢ per envelope, flat, and every one can go by email and text in one call.
You get a sandbox key on the next screen. Real delivery, not a simulation.
Check your email
We sent a sign-in link to . It is good for 15 minutes, and your sandbox key is waiting on the other side.
curl -X POST https://api.esigndev.com/v1/envelopes \
-H "Authorization: Bearer sig_sandbox_..." \
-H "Idempotency-Key: order-41882-contract-1" \
-H "Content-Type: application/json" \
-d '{
"document_name": "agreement.pdf",
"document_base64": "JVBERi0xLjQK...",
"delivery": "both",
"signer": {
"name": "Jane Smith",
"email": "[email protected]",
"phone": "+18135551212"
}
}'
No SDK to install, no OAuth dance, no field-placement editor to configure first. Bearer token, JSON body, a PDF you already know how to generate. The response carries an envelope id beginning with env_, and every response carries a request id beginning with req_, which is the difference between a support ticket that gets diagnosed and one that turns into a conversation.
There is no template system to learn and no coordinate map to maintain. You tag the PDF you are already producing, post it, and handle one webhook.
Put ^S1 where the signature goes and ^D1 where the date goes, in white text. Invisible to the reader, findable by us.
One JSON request with the file and the signer. Delivery by email, text or both starts immediately.
envelope.completed lands on your endpoint with a link to the signed PDF and its certificate.
| What | Siglio |
|---|---|
| Per envelope | 25¢ |
| Monthly fee | $0 |
| Per seat | $0 |
| Minimum | $0 |
| SMS delivery | Included, same 25¢ |
| Sandbox | 25 envelopes free, no card |
You are billed when an envelope is created, not when it is signed. A declined or ignored envelope still costs 25¢.
Two signers per envelope. PDF only, up to 15 MB, no encrypted files. Webhooks are included on every account, one endpoint per environment, all event types. Bearer token auth, no JWT assembly and no consent screen.
Yes. Sandbox delivers to real inboxes and real phones, so the first thing you test is the thing your signers will get. Send the first one to your own phone and watch it arrive.
Not with us. Signers get the completed PDF by email or text, good for 90 days with reissue. You get the signed result on the completion webhook, and you should download it there and keep your own copy. Your archive is your archive.
Sign up with an email address and your sandbox key is on screen in under a minute. The first 25 envelopes are free and no card is required. Most developers send their first test document in the same sitting they signed up.
The envelope sits in a sent state and you still paid the 25¢, because you are billed when an envelope is created rather than when it is signed. You can void it through the API, which stops the reminders.
One email address, no card, no company name, no sales call. The key is on the next screen.
You get a sandbox key on the next screen. Real delivery, not a simulation.
Check your email
We sent a sign-in link to . It is good for 15 minutes, and your sandbox key is waiting on the other side.
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