Alternatives · E-Signatures
SignatureAPI alternatives
As of Nov 13, 2026, the best SignatureAPI alternative for most people is BoldSign (3.0 GPA), first in our ranking of e-signature and proposal tools. It's also the best free one.
SignatureAPI compared with 5 alternatives: Anvil, Firma, eSignatures.io, BoldSign and Dropbox Sign.
SignatureAPI is a paid product with a free trial, starting at $25 per month, includes 100 completed envelopes. 3 of the 5 alternatives are free or have a free plan. 2 more offer a free trial.
Listings checked up to Nov 13, 2026 · Where the facts come from
Black Friday: is there a SignatureAPI sale?
At a glance
| Tool | Price | Free plan | Runs on |
|---|---|---|---|
| SignatureAPIThis tool | Free trial · from $25/mo | Trial only | Web |
| Anvil | Free plan · from $99/mo | Yes | Web |
| Firma | Free trial · from €0.049 | Trial only | Web |
| eSignatures.io | Free trial · from $0.49 | Trial only | Web |
| BoldSign | Free plan · from $5/mo | Yes | Web, iOS, Android |
| Dropbox Sign | Free plan · from $15/mo | Yes | Web |
Price against what you get
SignatureAPI starts at $25 a month and scores 2.0 out of 4 on features, ease of use and platforms. 2 of the 3 alternatives on this chart score higher and start lower: BoldSign and Dropbox Sign.
Anvil scores higher without starting lower.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
How each one differs from SignatureAPI
Anvil
Document automation and e-signature APIs for developers
- Anvil starts at $99 per month (AI Pack, billed monthly).
- Anvil has a free plan, which SignatureAPI lacks.
- Anvil also covers forms.
- Anvil does not cover AI agents, which SignatureAPI does.
Suits: Product teams embedding signing in their own app
Firma
Pay-per-envelope e-signature API for SaaS products
- Firma starts at €0.049 per envelope, no minimum.
Suits: SaaS teams that want white-labeled signing for their own customers
eSignatures.io
Pay-per-contract e-signatures with an API and no monthly fee
- eSignatures.io starts at $0.49 per contract, prepaid in credits from $50.
- eSignatures.io also covers documents.
- eSignatures.io does not cover AI agents, which SignatureAPI does.
Suits: Low-volume senders who do not want a monthly subscription
BoldSign
Low-cost e-signature app and API from Syncfusion
- BoldSign starts at $5 per user / month, billed yearly ($15 billed monthly).
- BoldSign has a free plan, which SignatureAPI lacks.
- BoldSign also lists iOS and Android apps.
- BoldSign also covers documents.
- BoldSign does not cover workflow automation and AI agents, which SignatureAPI does.
Suits: Individuals and micro-businesses who send up to 25 documents a month for free
Dropbox Sign
E-signature app from Dropbox with unlimited requests on paid plans
- Dropbox Sign starts at $15 per month, billed yearly ($20 billed monthly).
- Dropbox Sign has a free plan, which SignatureAPI lacks.
- Dropbox Sign also covers documents.
- Dropbox Sign does not cover workflow automation and AI agents, which SignatureAPI does.
Suits: Freelancers and small teams who send many agreements and want no per-envelope limit
Limits worth knowing in SignatureAPI
- Only completed envelopes, signed by every recipient, are billed; the $0.25 rate applies after the first 100 each month.
- An envelope holds at most 10 documents and 10 signers.
- The vendor classifies its signatures as eIDAS simple electronic signatures (SES), not advanced or qualified ones.
- Annual billing and prepaid credits are not self-serve; the vendor says to contact it.
Common questions
What are the alternatives to SignatureAPI?
The alternatives to SignatureAPI in this directory are Anvil, Firma, eSignatures.io, BoldSign and Dropbox Sign. Each one has a side-by-side comparison with SignatureAPI.
Is there a free alternative to SignatureAPI?
Yes. Anvil, BoldSign and Dropbox Sign have a free plan alongside paid ones.
Which SignatureAPI alternatives work on Android?
The SignatureAPI listing does not include an Android app. BoldSign lists one.
Which SignatureAPI alternatives work on iOS?
The SignatureAPI listing does not include an iOS app. BoldSign lists one.
When were these prices checked?
Each listing shows its own date. On this page they run from Oct 17, 2026 to Nov 13, 2026. Vendors change prices without notice, so confirm on their site before you buy.