Head to head · Esign send · October 2026 research run
Dropbox Sign vs airSlate SignNow
Dropbox Sign and airSlate SignNow score within a point of each other on agent readiness, 68.9 (B) and 68.5 (B). airSlate SignNow leads on reliability, payments & pricing and transparency & trust. Both do esign send.
Which one, for what
Good for An agent that sends a prepared PDF or a saved template for signature from one company account and tracks it to completion by webhook or polling, with the signed PDF and audit trail at the end.
Ahead on
- Schema & documentation, 88 against 81
- Agent ergonomics, 72 against 66
- Maintenance & community, 85 against 72
Watch for
No idempotency keys found in the docs or the spec, so a retried send can create a second signature request
Good for An agent that sends agreements from templates, embeds signing in another product or tracks invites, and teams that want per-invite pricing with a free test mode.
Ahead on
- Reliability, 93 against 75
- Payments & pricing, 35 against 25
- Transparency & trust, 74 against 68
Also in its favour
- Runs on your own machine
Watch for
API keys don't expire and work for all API requests. Narrower access needs an OAuth token requested with a URL-pattern scope
Score by category
| Category | Weight this run | Dropbox Sign | airSlate SignNow | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 75 | 93 | airSlate SignNow +18 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 88 | 81 | Dropbox Sign +7 |
| Agent ergonomics | 13%16.2 | 72 | 66 | Dropbox Sign +6 |
| Security & auth | 14%17.5 | 65 | 62 | Dropbox Sign +3 |
| Payments & pricing | 10%12.5 | 25 | 35 | airSlate SignNow +10 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 85 | 72 | Dropbox Sign +13 |
| Transparency & trust | 7%8.8 | 68 | 74 | airSlate SignNow +6 |
| Negative events | ≤15 | 0 | -2 | |
| Total | 68.9 · B | 68.5 · B |
Facts side by side
| Fact | Dropbox Sign | airSlate SignNow |
|---|---|---|
| Kind | HTTP API | HTTP API |
| Vendor | Dropbox, Inc. | airSlate, Inc. |
| Hosted endpoint | https://api.hellosign.com/v3 | https://api.signnow.com |
| Transports | HTTP | HTTP, Streamable HTTP, stdio |
| Auth | OAuth or key | OAuth or key |
| Pricing | Paid | Pay per use |
| x402 | no | no |
| Licence | Proprietary service under the Dropbox Sign terms of service. The OpenAPI spec repository is Apache 2.0 and the official SDKs are MIT | Proprietary service under the SignNow Terms of Service. The MCP server and the SDKs on GitHub are MIT |
| Tools exposed | none | 21 |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| MCP registry | not listed | io.github.signnow/sn-mcp-server |
| Last release | 2026-09-10 | 2026-09-03 |
| Terms last updated | 2025-01-07 | 2023-03-02 |
| Privacy policy last updated | 2025-01-14 | 2026-08-12 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | yes | yes |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | yes | yes |
| Popularity | 22 stars, 150k npm/wk | 8 stars, 7.7k npm/wk, 5.3k PyPI/wk |
Verdicts
Dropbox Sign
A public OpenAPI 3.0.3 spec, llms.txt, six official SDKs and a free test mode let an agent build the whole flow before paying. Production sends need a paid plan from $900 a year, the API key has full account access, and no idempotency keys were found in the reviewed documentation.
airSlate SignNow
The REST API has a public OpenAPI 3.0 spec with 354 operations, Markdown docs, a free Development mode with 500 invites and a hosted MCP server with OAuth. API keys don't expire and carry full account access, no idempotency keys were found, and the MCP server's GitHub repository was archived when checked on 7 October 2026.
Before you call either
Dropbox Sign
- Send
test_mode=truewhile building. Test requests are free, watermarked and not legally binding, and are limited to 10 requests a minute - Don't blind-retry a send after a timeout. No idempotency key exists, so list requests by
metadataor title first to check whether it was created - Authenticate with HTTP Basic, the API key as username and an empty password. Keep the key out of URLs, although the docs show that form
- Answer every webhook with HTTP 200 and the body
Hello API Event Received, and verifyevent_hash. Ten consecutive failures clear the callback URL - Treat a 200 from cancel as queued only. Confirmation arrives later as a
signature_request_canceledevent
airSlate SignNow
- Call https://api.signnow.com with
Authorization: Bearer <API key or access token>. Development and Live share this host, and Development documents carry a watermark - Request OAuth tokens with a narrow
scopesuch asdocument/* GET/user. The default*grants every API action - Read
X-RateLimit-RemainingandX-RateLimit-Reseton each response. The limit is 500 requests an hour in Development and 1,000 in Live, and 429 has no Retry-After - Check invite status before resending. No idempotency key exists, and a repeated invite call counts as another charged invite
- Set
secret_keywhen creating an event subscription and verifyX-SignNow-Signature(HMAC SHA-256 of the body) on every callback
Questions
Which is better for AI agents, Dropbox Sign or airSlate SignNow?
Dropbox Sign and airSlate SignNow score within a point of each other on agent readiness, 68.9 (B) and 68.5 (B). airSlate SignNow leads on reliability, payments & pricing and transparency & trust.
Do Dropbox Sign and airSlate SignNow need an API key?
Both take an API key or an OAuth sign-in.
Can an agent call Dropbox Sign and airSlate SignNow without installing anything?
Yes. Dropbox Sign has a hosted endpoint at https://api.hellosign.com/v3 and airSlate SignNow at https://api.signnow.com.
Other comparisons with Dropbox Sign or airSlate SignNow
Machine-readable
- This page as Markdown
/compare/dropbox-sign-vs-signnow.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/dropbox-sign.json·/api/v1/tools/signnow.json - From a terminal
anchor compare dropbox-sign signnow(the CLI) - Over MCP
compare_tools {"a": "dropbox-sign", "b": "signnow"}at/mcp, no key