Anvil vs SignatureAPI (2026): which should you pick?
As of Nov 13, 2026, Anvil grades higher than SignatureAPI: 2.2 against 2.0 out of 4.0.
Checked Nov 13, 2026 · graded Nov 13, 2026 by ToolGPA
Anvil grades higher on the free plan and ease of use. SignatureAPI grades higher on value for money. They get the same grade on features and platforms.
Price, platforms and features side by side. The table says where each price was read and when.
Anvil
Document automation and e-signature APIs for developers
SignatureAPI
E-signature API for developers, with a no-code connector
Which one is for you
Pick Anvil if
- Fits if you build document and signing flows into your own software
- Works for small teams that fill PDFs and send them for signing
Look elsewhere if
- Pricey if you want white labeling, which is on Product Pack at $425 a month
- Watch out: usage beyond included credits is $1.50 per e-sign packet, $0.10 per PDF fill and $1.00 per Workflow submission
- Tight if you want the API free, as keys need a card on file or a paid plan
- Watch out: native Salesforce and HubSpot links are listed as coming soon
Pick SignatureAPI if
- Fits if you are building signing into your own product
- Works for developers who want to pay per completed envelope
Look elsewhere if
- Not for you if you have no developer, since it is an API with only connectors for no-code
- Watch out: the signatures are eIDAS simple only, not advanced or qualified
- Tight if your envelopes are large, as the limit is 10 documents and 10 signers
- Watch out: annual billing and prepaid credits are not self-serve
How we grade them
| 2.2GPAAnvilFair | 2.0GPASignatureAPIFair | |
|---|---|---|
| Value for money | DAI Pack is $99 a month and Product Pack $425 monthly ($340 yearly), several times the category's $20 middle. White labeling and in-person signing sit on the dearer one. | CStandard is $25 a month with 100 envelopes included, then $0.25 each, just above the category's $20 middle. Extra dashboard users are $20 each. |
| Free plan and trial | BA free plan for 2 users with unlimited templates, the UI, an audit trail and a sandbox. API access needs a card on file. | CA free test account with no time limit and no card, but it is for testing, and sending for real needs Standard. |
| Features | CE-signature API, white-labeled signing, document AI, PDF fill, web forms and workflows. White labeling and several signing modes need Product Pack, and Salesforce and HubSpot links are listed as coming soon. | CEnvelope API, templates, signing with no account, sealed documents, audit log, branding and webhooks. An envelope holds at most 10 documents and 10 signers, and signatures are simple only. |
| Ease of use | CNo store rating on record, and the product is aimed at developers who build workflows and call an API. | DNo store rating on record, and it needs developers to write code against an API before anyone signs anything. |
| Platforms and integrations | BWeb and API, with Zapier as the current connector. | BWeb and API, with Power Automate and Zapier connectors. |
| Best for | e-signature and PDF APIs for developers | adding e-signatures to your own app |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: Anvil and SignatureAPI. How we grade
Price against what you get
Anvil starts at $99 a month and scores 2.3 out of 4 on features, ease of use and platforms. SignatureAPI starts at $25 a month and scores 2.0.
Anvil scores higher, and starts $74 a month higher: the question is whether the extra is worth that to you. Of the other e-signature and proposal tools on the chart, 15 score higher than Anvil for less, and 29 score higher than SignatureAPI for less.
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
Where they differ
- Anvil also covers forms.
- SignatureAPI also covers AI agents.
At a glance
| Anvil | SignatureAPI | |
|---|---|---|
| Pricing | Free plan | Free trial |
| Starts at | $99 per month (AI Pack, billed monthly) | $25 per month, includes 100 completed envelopes |
| Free plan | 2 users, unlimited templates and UI use, multiple signers, embedding and a sandbox. API keys need a card or a paid plan. | None |
| Free trial | None listed | Free test account with no time limit, no card required |
| Web | ||
| Made by | Anvil | Signature API, Inc. |
| Price read from | useanvil.com | signatureapi.com |
| Checked | Nov 13, 2026 | Nov 13, 2026 |
Worth knowing
Anvil
- Usage beyond included credits is metered: $1.50 per completed Etch e-sign packet, $0.10 per PDF fill and $1.00 per Workflow submission.
- The monthly figures shown are for monthly billing; annual billing takes 20% off ($340 a month for Product Pack).
- White labeling and interactive, progressive and in-person signing over the API need Product Pack or Enterprise.
- Native Salesforce and HubSpot integrations are listed as coming soon; Zapier is the current route.
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.
Key features
Anvil
- Etch e-signature API
- One API call creates a signature packet with signers, fields and order. Signing is URL-based and works in a phone or desktop browser.
- Embedded, white-labeled signing
- Signers can sign inside an iframe in your own product, with CSS styling to match your brand. White labeling is on Product Pack and above.
- Document AI
- Upload a PDF and Anvil identifies input and signature fields and signers, producing a template ready to send.
- PDF fill and generation
- APIs fill PDF templates with data or generate PDFs from HTML or Markdown.
- Webforms and Workflows
- Mobile-friendly forms collect data and feed Workflows that fill documents and route them for signature.
- Sandbox and audit trail
- Every plan includes a sandbox for test packets, and each completed packet has an audit trail with timestamps, IP address and a document hash.
SignatureAPI
- Envelope API
- One call creates an envelope with up to 10 documents and up to 10 signers, routed in parallel or in sequence.
- Document templates
- Start from a .docx file with placeholders and fill it with data from your own system before the document goes out for signature.
- Accountless signing
- Signers open a link and sign from a desktop or phone browser without creating an account.
- Sealed documents and audit log
- The finished file holds the signed documents and a log of who opened it and what they did, cryptographically sealed against changes.
- Branding and languages
- Logo and brand colors can be applied to the signing page and recipient emails, and the interface language, date format and time zone can be set.
- Webhooks and no-code connectors
- Webhooks and emails report signing activity in real time. Power Automate and Zapier connectors and an AI toolkit are offered for non-developers and agents.
Plans
Anvil
Free$0
2 users, unlimited templates, Document AI in the UI, audit trail and sandbox. API access needs a card on file.
AI Pack$99
per month, billed monthly
5 users, programmatic Document AI, 50 pages per AI-tagged PDF and a 40 requests/second limit.
Product Pack$425
per month, billed monthly ($340 billed annually)
AI Pack plus white labeling, interactive, progressive, parallel and in-person signing.
EnterpriseCustom
Unlimited users, single sign-on, HIPAA and DPA terms, embedded builders and priority support.
SignatureAPI
Standard$25
per month, includes 100 envelopes
First 100 envelopes included, then $0.25 each. One dashboard user included, extra users $20 each.
EnterpriseCustom
Annual contracts, prepaid credits, SLAs and dedicated Slack support, sold through sales.
Ways to pay less
Anvil
- Annual discount
20% off annual plans
The pricing FAQ says annual plans are discounted 20%, giving $340 a month for Product Pack instead of $425.
SignatureAPI
No public discounts listed.
Common questions
Which is cheaper, Anvil or SignatureAPI?
As of Nov 13, 2026, SignatureAPI is cheaper to start with: $25 a month, against $99 a month for Anvil. Anvil starts at $99 per month (AI Pack, billed monthly), and SignatureAPI starts at $25 per month, includes 100 completed envelopes.
Which has a free plan, Anvil or SignatureAPI?
As of Nov 13, 2026, only Anvil has a free plan. SignatureAPI does not, though it has a free trial.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.