A year ago, adding document signing to a software product meant reading API documentation, writing integration code by hand, and debugging authentication flows. Today, a growing number of developers are building entire applications by describing what they want in plain English, and the AI writes the code for them.
This approach, sometimes called “vibe coding,” has gone from a novelty to a legitimate way that startups and solo developers ship production software.
Platforms like Lovable, Bolt.new, Cursor, and Replit let builders go from idea to functional product in a matter of days. And it’s starting to reshape which infrastructure tools succeed and which ones get left behind.
E-signature APIs are a clear example. The tools that were built for enterprise procurement cycles and multi-week integration timelines are a poor fit for a developer who plans to have a working product by Friday.
What vibe coders actually need from an e-signature API
Developers building with AI coding tools have a specific set of requirements, and they’re very different from what enterprise buyers look for.
They need pricing that starts at zero and scales with usage. Committing to a monthly subscription before the product has users doesn’t make sense when the whole point of vibe coding is to test ideas quickly and discard the ones that don’t work.
Pay-as-you-go pricing lets developers add electronic signatures to ten different prototypes without worrying about the bill, then scale up the one that gains traction.
They need documentation that AI assistants can actually read and work with. This is an underappreciated point.
When a developer asks Cursor or Claude to “add e-signatures to my app,” the AI model needs to find correct, well-structured API documentation to generate working code. Poorly documented APIs produce broken integrations and hours of debugging, which defeats the entire purpose of using AI to build faster.
And they need an API that’s comprehensive enough to handle real production use cases, not just a demo. Template management, embedded signing flows, webhook notifications, white-labeling, multi-tenant customer separation.
These features matter just as much in a vibe-coded product as in one built the traditional way, because the end users don’t know or care how the software was made.
The infrastructure layer is adapting
Firma.dev, the cheapest e-signature API on the market at $0.03 per envelope, was built with exactly this kind of developer workflow in mind.
The API is free to get started with real documents, charges nothing until you’re ready to scale, and covers a wider surface area than most enterprise alternatives despite costing a fraction of the price.
But what makes it particularly relevant for the vibe coding generation is its approach to AI-native tooling. Firma.dev publishes MCP servers that connect directly to AI coding assistants like Claude, ChatGPT, Cursor, GitHub Copilot, and Replit.
MCP, or the Model Context Protocol, is an open standard that lets AI models interact with external APIs through natural language rather than manual code.
In practice, this means a developer can tell their AI assistant to “create a signing template with fields for name, date, and signature” and the AI calls the Firma.dev API directly.
No boilerplate, no reading docs line by line, no copy-pasting code snippets. The AI handles the integration while the developer focuses on the product.
Firma.dev publishes two MCP servers: one that gives AI assistants live access to the API for managing templates, sending signing requests, and configuring workspaces, and another that provides the full documentation and API reference so AI models generate accurate integration code from the start.
Why this matters beyond the vibe coding community
The shift isn’t limited to solo builders and weekend projects. The same forces that make vibe coding popular, faster iteration, lower upfront costs, AI-assisted development, are being adopted by engineering teams at organizations of all sizes.
Tools like Claude Code are now handling the majority of coding work at companies ranging from two-person startups to established enterprises.
The expectation that infrastructure should be easy to integrate, transparent in pricing, and compatible with AI workflows is spreading across the entire developer market.
E-signature providers that still require sales calls, annual contracts, and complex onboarding processes are going to find themselves competing for a shrinking segment of the market.
The next generation of developers picks tools the way they write code: quickly, based on documentation quality, and with a strong preference for usage-based pricing.
At $0.03 per envelope and an API designed to work natively with AI assistants, Firma.dev represents where developer infrastructure is heading.
The companies that adapt to this model will capture the next wave of SaaS products being built today. The ones that don’t will keep selling to the same enterprise customers they always have, while the rest of the market moves on.
