For developers · 25¢ per envelope · No monthly fee

Building an e-signature integration? Compare before you commit.

Siglio vs. DocuSign for developers

Get your API key in about a minute and 25 free documents, no card and no account review. Then 25¢ per envelope, flat, delivered by email and text.

✓25¢ per envelope, no seats ✓Email and text ✓API key in a minute

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Next to the market

	Per envelope	SMS delivery	Monthly fee
Siglio	25¢	Yes, included	None
eSignatures.com	49¢	Yes, 9¢ extra per text	None
Documenso	Not published	Not mentioned	$25 to $250/mo, or self-host
DocuSign	Not published	Not on the Starter or Intermediate API plans; eSignature add-on from $0.36 per delivery	$50 to $480/mo (API plans)
Adobe Acrobat Sign	Not published	Not published	Not published for API tiers
PandaDoc API	Not published	Email or SMS listed, price not published	$40/mo Developer plan, 40 documents

Each company’s figures are from its own published pricing page, linked from its name, checked 7 October 2026. DocuSign’s SMS add-on is from its eSignature plans page; its API plans list SMS as “Does Not Include” on Starter and Intermediate. Adobe’s Acrobat Sign API FAQ says API access is “reserved exclusively for enterprise and developer tier accounts” and prices neither. Documenso’s page does not mention SMS. “Not published” means the page does not state it. Prices change; check the source before relying on it. Longer comparisons: DocuSign, PandaDoc, Adobe Sign.

# Tag the PDF with ^S1 where they sign, then:
B64=$(base64 < agreement.pdf | tr -d '\n')

curl -X POST https://api.esigndev.com/v1/envelopes \
  -H "Authorization: Bearer sig_..." \
  -H "Idempotency-Key: order-41882-contract-1" \
  -H "Content-Type: application/json" \
  -d '{
    "document_name": "Roof replacement agreement",
    "document_base64": "'"$B64"'",
    "delivery": "both",
    "signer": {
      "name":  "Jane Smith",
      "email": "jane@example.com",
      "phone": "+18135551212"
    }
  }'

# POST to your webhook endpoint when the last signature is in
{
  "id": "evt_8f3k2m9q1x",
  "type": "envelope.completed",
  "occurred_at": "2026-09-28T15:04:11.482Z",
  "data": {
    "envelope": {
      "id": "env_k7m2v9x3q1",
      "state": "completed",
      "document_name": "Roof replacement agreement",
      "delivery": "both",
      "signer": {
        "name": "Jane Smith",
        "signed_at": "2026-09-28T15:04:09Z"
      },
      "completed_at": "2026-09-28T15:04:09Z"
    }
  }
}

# then fetch the signed PDF, certificate included:
curl https://api.esigndev.com/v1/envelopes/env_k7m2v9x3q1/document \
  -H "Authorization: Bearer sig_..." -o signed.pdf

One POST creates the envelope and sends it. Bearer token, no JWT, no consent screen. The webhook body is trimmed to the fields you act on; the full shape is in the docs.

25¢

per envelope, flat at every volume. No monthly fee, no seats

SMS

and email, or both, in one API call, included in the 25 cents

ESIGN

and UETA, with a certificate page for each signer on every signed PDF

30 days

signed copies are kept after the envelope closes, then deleted

Side by side

What each one costs, and what each one includes

	Siglio	DocuSign Developer Starter	DocuSign Developer Intermediate
Price per envelope	25¢	Not published	Not published
Monthly fee	$0	$50	$300
Per-seat fee	$0	Not published	Not published
Minimum commitment	$0	Not published	Not published
SMS delivery	Included at the same 25¢	“Does Not Include”	“Does Not Include”
Free trial access	Key on screen in about a minute. No card, no account review.	Free developer account, no card	Free developer account, no card
Webhook on every event	Every event type, every account	Not published	Not published
Multi-signer	Two per envelope; signer two is notified after signer one finishes	Not published	Not published

DocuSign figures are quoted from DocuSign's published developer plans page and eSignature plans page, checked on 7 October 2026. Envelope allowances are quoted as “Starting amount of 40 envelopes/month” and “Starting amount of 100 envelopes/month”; the price of an envelope beyond the allowance is not stated on either page. Sandbox wording is theirs: “Developer accounts operate in a Docusign non-production (demo) environment. They have most enterprise features enabled by default and don't expire.” A cell reading “Not published” is not stated on those pages, which is not the same as saying it does not exist. On the eSignature side, SMS delivery is sold as an add-on “Starting at $0.36/delivery”, added to a Standard or Business Pro plan. Prices change; check the source before relying on it.

On the free trial row, the practical difference: signing up here is an email address and a magic link, and the key is on the screen that follows. No account review, no card, and the 25 free documents deliver to real inboxes and real phones rather than a simulation. DocuSign’s developer account is also free and needs no card; what their page does not state is how long it takes to have a key in your hand, so we have not put a number on it.

Switching

Moving a small integration over

Auth is a Bearer token in the Authorization header. No JWT and no consent screen.
One POST creates and sends the envelope: the PDF, the signer, and delivery by email, text or both.
Webhooks are on every account, for every event type. Point one endpoint at them.
The signed PDF comes back by id. On envelope.completed, download it by the envelope id and keep your copy: Siglio deletes it 30 days after completion.

How it works

The e-signature API in three steps

One endpoint and one event. If the integration you are picturing is an SDK, a template system and a field editor, this is smaller than you expect.

Tag the PDF

Put ^S1 where the signature goes and ^D1 where the date goes, in white text. Invisible to the reader, findable by us.

POST it

One JSON request with the file and the signer. Delivery by email, text or both starts immediately.

Get the webhook

envelope.completed lands on your endpoint with the envelope id. Download the signed PDF, certificate included, and keep it.

Pricing

What it costs

What	Siglio
Per envelope	25¢
Monthly fee	$0
Per seat	$0
Minimum	$0
SMS delivery	Included, same 25¢
Free trial	25 free documents, no card

You are billed when an envelope is created, not when it is signed. A declined or ignored envelope still costs 25¢.

Legal standing

Legally binding, with the record to show it

ESIGN ActFederal, 15 U.S.C. §7001 UETA49 states, D.C., Puerto Rico, U.S.V.I.

Electronic signatures have carried the same legal force as ink in the United States since 2000, under the federal ESIGN Act and, at state level, the Uniform Electronic Transactions Act. Every signed PDF carries a certificate page per signer with the sent, viewed and signed times and the IP address each came from. How the record holds up.

Questions

The fair version of the comparison

Why are so many competitor cells blank?

Because the rule for this page is that a competitor figure comes from the competitor’s own published page or it does not go in the table. DocuSign publishes plan prices and included allowances; it does not publish a per-envelope rate, a seat fee or a minimum on those pages. “Not published” means we could not source it, not that it does not exist.

How does 25¢ compare to a plan?

There is no plan to compare. 25¢ per envelope, flat, at every volume, with no tiers. $0 monthly fee, $0 per seat and $0 minimum, so your monthly envelopes times 25¢ is the bill.

Do I need a consent screen?

No. Every call carries a Bearer token. No JWT and no consent screen. Your API key is on screen in about a minute, with no account review, and the 25 free documents deliver to real inboxes and real phones.

Is SMS extra?

No. Email and text go out in the same API call at the same 25¢. There is no SMS surcharge.

Is it legally binding?

Yes. Electronic signatures carry the same legal force as ink in the United States under the federal ESIGN Act and state UETA. Every signed PDF includes a certificate page per signer with the timestamps and IP addresses. More on the law.

What are the limits?

Two signers per envelope, signer one first: signer two is notified only after signer one signs. PDF only, up to 15 MB. Signed documents are deleted 30 days after completion, so download the signed PDF by id on the completion webhook and keep it.

Get your API key and decide afterwards

One email address, no card, no call. 25 free documents that deliver for real.

Continue with Google

or use your work email

You get your API 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 API key is waiting on the other side.