APISign

APISign is an API-first electronic signature platform that lets developers send, track, and automate legally binding contracts through code rather than manual workflows. The entire system runs on a pay-per-contract model at 25 cents per document with no monthly subscriptions, per-seat fees, or minimum commitments. Templates live in Markdown with variable placeholders, and the platform handles everything from delivery to audit trails to webhook notifications when signers take action. Contracts deliver instantly with no processing delays, and signers can review and sign immediately from any device.

The problem it addresses is the cost and complexity of enterprise e-signature tools when all you need is programmatic document signing. Services like DocuSign and PandaDoc charge monthly fees starting around $25 to $65 per user, plus per-document fees ranging from $1.50 to $3.00 or more. For developers building contract workflows into their products, those costs add up fast and the manual interfaces get in the way. APISign strips all of that down to a simple API call and a flat fee per contract sent. There are no negotiations, no sales calls, and no enterprise tiers to navigate.

Templates use Markdown syntax with dynamic variable substitution. You define a contract once with placeholders for things like signer name, date, dollar amounts, or any custom fields, then reference that template by ID when sending through the API. The platform renders the Markdown into a clean document for signers, who can review and sign immediately without downloading anything. Formatting stays intact, including headings, lists, tables, and any structure you build into the Markdown source. Because templates are plain text Markdown, you can version control them alongside your application code and track changes over time just like any other source file.

If you have existing Word documents, there is a drag-and-drop importer that converts them to Markdown templates while preserving formatting. This makes migration practical for teams that already have a library of contracts in traditional formats. You upload the document, the platform converts it, and you can then edit the result to add variable placeholders where needed. The conversion preserves headings, lists, tables, and basic formatting so you are not starting from scratch.

The technical integration follows standard REST patterns. You authenticate with an API key, post to an endpoint with template ID, signer information, and variable values, then receive webhook callbacks as the contract moves through its lifecycle. Events fire when the signer views the document, when they sign, when they decline, and when the contract expires. Every interaction gets logged with IP addresses and timestamps for audit purposes. SDKs exist for common programming languages, and there is also an MCP server available for developers who want to integrate contract signing into AI agent workflows through tools like Claude Desktop or Cursor.

Beyond the core signing flow, the platform includes an AI assistant called Gilberto that helps draft and edit documents through conversational prompts. There is also automatic document review that scans contracts before sending to catch errors, grammar issues, missing variables, and formatting problems. The review system checks for compliance concerns and validates that required clauses are present. This catches mistakes before they reach signers rather than after, which saves the back and forth of sending a broken contract and having to void and resend it.

Pricing stays simple. Every contract sent costs 25 cents. New accounts start with 20 free contracts included. There are no hidden fees for storage, for team members, or for completed documents sitting in the system. If your balance runs out, the API returns a 402 error until you add more funds. You can enable auto-reload to avoid interruptions, or manually add credit as needed. The pay-as-you-go model means you only pay for what you actually send, which makes it predictable for budgeting even at high volumes.

The target audience is developers and technical teams building products that generate contracts, onboard users with agreements, or automate any workflow requiring legally binding signatures. SaaS platforms, marketplaces, HR systems, and any application that needs embedded signing without manual intervention fits the use case. The trade-off is clear: there is no visual drag-and-drop builder for non-technical users. If you are not comfortable working with APIs and Markdown, you will need developer help to set it up. For teams that are already code-first, that is a feature rather than a limitation.

Test mode mirrors production exactly but does not deduct from your balance, so you can build and debug integrations without burning through credits. The audit trail provides legal-grade documentation of every action taken on every contract, which matters when signatures need to hold up to scrutiny.