Signbee Review 2026: API, MCP, Pricing & Limits

The direct verdict: Signbee is a compelling low-cost e-signature API for developers and AI-agent builders whose recurring job is to send one document between one sender and one recipient. Its markdown input, optional API key, documented four-endpoint REST surface, and published MCP package remove setup from that narrow workflow. It is a weaker fit when agreements require several signers, reusable roles, ordered approvals, advanced branding, enterprise administration, or qualified electronic signatures.

This is a documentation-based Signbee review, not a hands-on product test. No live document was sent, no signing ceremony was completed, and no certificate, delivery time, support response, or production reliability was independently tested. The findings come from Signbee's public homepage, documentation, about page, terms, and llms.txt, rechecked on July 18, 2026. Product and legal statements from those pages are identified as vendor claims; practical judgments are editorial conclusions.

Signbee review summary

How this review separates facts, claims, and conclusions

This distinction matters because a well-written API page can prove that an interface is documented, but not that emails arrive quickly, examples work without adjustment, the mobile ceremony is clear, or the service meets a buyer's uptime needs. MCP presence, endpoint count, OpenAPI, and llms.txt likewise show integration intent and discoverability; none is evidence of product quality on its own.

What Signbee is

Signbee is an API-first e-signature service operated by B2bee Ltd and positioned for developers and AI agents. The public workflow accepts document content, verifies a sender, emails one recipient, collects the recipient's signature, and returns a completed PDF. Signbee exposes that workflow through REST, an MCP server, an Agent Skill, an OpenAPI specification, and machine-readable llms.txt.

Its defining product decision is scope. Signbee documents two-party e-signing rather than a configurable envelope with many recipients. A request contains one recipient, while the lifecycle moves from pending_sender to pending_recipient and then signed. That model can be an advantage when it matches the job: there are fewer resources and states for an integration to manage. It becomes a functional boundary when the real agreement needs legal, finance, a client, and a countersigner in one coordinated process.

Features at a glance

Signbee API review

The REST API is the clearest part of Signbee's proposition. It uses JSON over HTTP and explicitly recommends native language clients rather than a vendor SDK. Four operations cover send, markdown preview, status retrieval, and revocation. That small surface is not inherently better or worse than a larger API; it is efficient only when it exposes every state the buyer's workflow needs.

The documented input contract is practical. Markdown supports common structural elements and removes a PDF-generation dependency from text-first automations. Existing PDFs must be reachable through a URL, so teams should confirm how source files are hosted, protected, fetched, and retained before sending sensitive material. The reviewed pages do not answer every privacy or data-location question that may follow from URL ingestion.

No-key mode is unusual and useful for evaluation: the caller provides sender identity details, and the sender verifies by email OTP before the recipient is contacted. Production automation is cleaner with an API key because the sender is pre-verified. The API key must still be treated as a signing-workflow credential, scoped and stored accordingly; Signbee's terms place responsibility for key security on the account holder.

MCP and AI-agent operability

Signbee publishes an npm package named signbee-mcp. Its first-party configuration runs the package through npx and passes SIGNBEE_API_KEY as an environment variable. The homepage and llms.txt list two tools: send_document for markdown and send_document_pdf for an existing PDF URL. The docs also describe a send_document tool more generally.

Editorial conclusion: the MCP package is most valuable when it preserves the same narrow, understandable boundary as the REST API. An agent can prepare and send a request, while a person receives and completes the signing action. Buyers should test tool discovery, argument validation, duplicate-send behavior, cancellation, and error recovery before treating the package as production-ready.

The documented signing workflow, step by step

The lifecycle names six states: draft, pending_sender, pending_recipient, signed, expired, and revoked. That is enough to model a simple ceremony. It does not expose partial progress among several recipients because the public request does not model several recipients. Teams should avoid simulating a multi-party agreement as unrelated two-party sends unless legal and operational owners accept separate documents, evidence records, and failure states.

Certificate, audit evidence, and legal claims

Signbee states that a completed document receives a SHA-256 signing certificate. Its terms say the service stores timestamps, IP addresses, and signature images, while other first-party materials describe party details, a document hash, and a verification URL. These are Signbee vendor claims because this review did not complete a transaction and inspect the resulting PDF or independently reproduce the hash.

Signbee's terms identify its output as Simple Electronic Signatures and state that signatures are intended to be valid under the US ESIGN Act, EU eIDAS Regulation, and UK Electronic Communications Act. The same terms say Signbee does not guarantee acceptance by every court or regulatory body. This review treats the legal statements as vendor positioning, not accreditation, a legal opinion, or proof that every document type and jurisdiction is supported.

A buyer should evaluate signer intent, consent language, identity evidence, authority, delivery records, retention, document exclusions, and applicable law alongside the hash. If Advanced or Qualified Electronic Signatures are required, Signbee's own terms direct users to seek legal counsel; the product is not presented as QES.

Signbee pricing — retrieved July 18, 2026

The Free and Pro prices were consistent across the first-party pages reviewed. Business was not. Signbee's homepage, about page, Terms of Service, and llms.txt listed Business at $19 per month for unlimited documents. The live API documentation rate-limit table listed Business at $29 per month for unlimited documents. This unresolved $19/$29 discrepancy is material, so confirm the checkout amount, taxes, email limits, and applicable terms before buying.

The terms state that paid plans are billed monthly through Stripe and that cancellation takes effect at the end of the billing period. The documentation says monthly document limits reset on the first day of each month and returns HTTP 429 with Retry-After when a rate limit is reached. “Unlimited” should therefore be read alongside the documented email rate and acceptable-use terms rather than as unlimited instantaneous throughput.

Security, privacy, and procurement questions

The terms provide useful baseline disclosures: B2bee Ltd operates the service, users are responsible for API-key security, paid billing runs through Stripe, a 99.9% uptime target is not guaranteed, and liability is limited under the agreement. An uptime target is not observed uptime, and this review found no independent operational data with which to assess reliability.

Signbee strengths

• A focused two-party workflow that is easy to understand from the public documentation.
• Markdown-to-PDF input removes a document-generation step for text-first agents and automations.
• A PDF URL path supports documents that already exist outside Signbee.
• No-key sender OTP creates a low-friction prototype path without pretending verification is unnecessary.
• Native HTTP avoids a mandatory SDK and makes the request portable across languages.
• Status retrieval and revocation cover the essential operational controls for pending documents.
• The published MCP package, Agent Skill, OpenAPI, and llms.txt offer several machine-integration paths.
• Five production documents per month at no cost is useful for genuinely low-volume workflows.
• The vendor is explicit that its signatures are SES rather than QES.

Signbee limitations and unknowns

• The documented send request has one recipient, so it does not cover multi-party routing or ordered approval chains.
• Reusable templates, signer roles, and visual field placement are not described in the reviewed documentation.
• Webhook delivery is not documented; the status workflow uses authenticated polling.
• Custom signing domains and detailed branding controls were not established from the reviewed pages.
• The actual signing page, mobile usability, emails, and completed certificate were not hands-on tested.
• Independent reliability, support responsiveness, and delivery data were not found.
• Data retention, residency, subprocessors, DPA availability, and incident commitments require direct confirmation.
• The live Business price conflicts between $19 and $29 per month.
• The terms target 99.9% uptime but explicitly do not guarantee it.
• The product is described as SES, not a QES or high-assurance identity service.

Who Signbee is best for

Signbee alternatives

Alternative features and prices change frequently; the table identifies evaluation directions rather than claiming current plan parity. Start with the signing ceremony and evidence requirement, then compare live vendor documentation and contracts.

Final Signbee review verdict

Signbee deserves consideration on its actual merits: a clearly documented, inexpensive path from markdown or a PDF URL to a two-party signature. For an indie developer, lightweight automation, or agent sending a straightforward agreement to one recipient, that focus can be exactly right. There is no reason to buy multi-party routing, elaborate templates, or enterprise controls when the workflow never needs them.

The same focus sets the ceiling. A buyer should move beyond Signbee's documented model when one agreement needs several people, approval order, reusable signer roles, deep brand control, formal procurement commitments, or qualified signatures. Before production adoption, run a real API-key send and no-key OTP send, inspect the completed certificate, reproduce its hash, test recipient delivery, exercise MCP errors and duplicate requests, and get written answers to the privacy and pricing questions above.

Frequently asked questions

What is Signbee?

Signbee is an API-first e-signature service operated by B2bee Ltd. Its documented workflow accepts markdown or a PDF URL, verifies a sender, emails one recipient for signature, and provides a completed PDF. It also publishes an MCP server, Agent Skill, OpenAPI specification, and llms.txt.

Is this a hands-on Signbee review?

No. This is a documentation-based review using Signbee's first-party pages retrieved on July 18, 2026. No live send, signing ceremony, email delivery, MCP execution, support interaction, reliability measurement, or certificate inspection was performed.

Is Signbee free?

Signbee's live first-party pages listed a Free plan with five documents per month and no credit card requirement on July 18, 2026. The API docs also listed an email rate of one per minute. Confirm the current allowance in the dashboard before relying on it.

How much does Signbee cost?

Free was listed at $0 for five documents per month, and Pro at $9 per month for 100 documents. Business had an unresolved conflict: the homepage, about page, terms, and llms.txt showed $19 per month, while the API docs showed $29. Both called the document allowance unlimited.

Why do Signbee's Business prices differ?

The public first-party sources were inconsistent when retrieved. This review cannot determine whether the $29 documentation row is stale, anticipatory, or applies differently from the $19 product and terms price. Confirm the amount and terms at checkout or ask Signbee in writing.

Does Signbee support multiple signers?

The public API documentation reviewed describes two-party signing with one sender and one recipient. The send request accepts one recipient, and the lifecycle tracks sender then recipient. Ask Signbee directly if a newer multi-signer workflow has launched after July 18, 2026.

Does Signbee have an MCP server?

Yes. Signbee publishes signbee-mcp and documents an npx configuration using SIGNBEE_API_KEY. Its first-party materials list tools for sending markdown and PDF URLs. The package was not installed or execution-tested for this review.

Can Signbee accept an existing PDF?

Yes. The send endpoint accepts pdf_url as an alternative to markdown. The PDF must be available through a URL, so buyers handling sensitive documents should confirm fetch behavior, access controls, retention, and exposure risks.

Does Signbee provide an audit trail?

Signbee states that completed documents include a SHA-256 certificate and that signing metadata includes timestamps, IP addresses, and signature images; other first-party pages also mention party details, a hash, and a verification URL. Those claims were not independently checked against a completed artifact in this review.

Are Signbee signatures legally binding?

Signbee says its Simple Electronic Signatures are intended to be valid under named US, EU, and UK laws, but its terms do not guarantee acceptance by every court or regulator. Enforceability depends on the document, intent, authority, identity evidence, ceremony, jurisdiction, and applicable exclusions. Obtain legal advice for the specific transaction.

Does Signbee support QES?

Signbee's terms describe Simple Electronic Signatures, not Qualified Electronic Signatures. If QES is mandatory, evaluate a qualified trust service provider with the required jurisdictional status.

Can Signbee be self-hosted?

Self-hosting is not offered in the public product materials reviewed for this article. That is a documentation finding, not a claim about private arrangements. Buyers requiring source control or on-premises deployment should ask Signbee or evaluate a self-hostable alternative.

What are the best Signbee alternatives?

Consider SumoSign for branded multi-party agent workflows, DocuSeal for open-source or self-hosted needs, BoldSign or Dropbox Sign for broader API surfaces, DocuSign for enterprise breadth, and a qualified trust service provider when QES is required. The best choice follows the signing ceremony and evidence requirement, not the endpoint count.