Two ways for AI to build an application
bolt.new, from StackBlitz, lets a Claude model write the application code directly in a conversation. WebContainer technology runs Node.js in the browser: file tree, terminal, package installs, live preview, with nothing to set up. You get a running project very quickly, and you refine it by asking the model to change the code, turn after turn.
Blueprint Maker deliberately separates two responsibilities. AI does what it does best, understand the business, and produces a specification: entities, relations, statuses, indicators, which you validate. Then deterministic builders, code we wrote, translate that specification into an application: a relational Prisma schema, the API, CRUD screens, a dashboard, demo data. AI never touches the structural code; it describes, it doesn't build.
The difference isn't cosmetic. When a model writes the code directly, every iteration is a fresh generation, with its share of randomness. When deterministic builders write the code from a specification, the same description produces the same code: it's reproducible.
The crux: iterating without breaking things
The most documented friction point of conversational generation is right here: a small change asked of the model can break another elsewhere, and fixing one bug can introduce a new one. A significant share of the effort, and of the cost, since bolt.new is billed by tokens, then goes into fixing bugs rather than creating value. This is a recognized pain point of the sector, not a flaw specific to one product: it stems from the very nature of letting a model rewrite code on every turn.
Blueprint Maker attacks the problem at the root, upstream. The specification is validated before any generation; the builders are deterministic and cover the exhaustive common trunk of a management application; and above all, every generated application goes through runtime validation, which we call K-15: it is actually built, started, and browsed automatically before being delivered to you. We don't measure quality by the feel of a conversation, but by the fact that the application starts and works.
As a result, there is no post-generation fixing phase on the user's shoulders for the application's structure. Technical conformance is correct by construction. You judge the result on screens filled with realistic data, not on a work site to debug.
A finished business app, or a free canvas
bolt.new is general-purpose and open: it can produce just about any modern web application, across a wide range of JavaScript frameworks, with great freedom of form. That's its strength for prototyping an idea, a landing page, an interactive demo, or exploring a direction without constraints.
Blueprint Maker is specialized: it produces one precise, well-made category, the business management application. From a description, you get a relational database, an API, list and detail screens with create, edit and delete, a KPI dashboard, and a coherent set of demo data. That tight scope is exactly what makes determinism possible: you can only guarantee by construction what you know how to build.
This layer goes beyond structure. Blueprint Maker also enforces data integrity: computed fields are recalculated server-side before writes, parent aggregates are derived from their children on read, chronological consistency rules and stock mutations are guarded deterministically. A displayed value cannot lie. That's the kind of guarantee that free-flowing code generation cannot offer systematically.
The code, the hosting, what you keep
Both products hand you real code, and that's a good thing. bolt.new lets you export the project to GitHub and deploy, notably to Netlify, right from the window. Blueprint Maker exports standard Next.js + Prisma, as a ZIP archive or via GitHub push, and provides a dedicated hosting URL in France / EU, with the database included.
The difference is in what you get back. With bolt.new, you get the fruit of a conversation: code whose shape depends on the thread of exchanges. With Blueprint Maker, you get the output of a deterministic pipeline: a regular project structure, the same from one application to the next, that a developer picks up without having to untangle its history. In both cases the code is yours; in one case it's reproducible.
On billing, bolt.new works on token consumption, the more complex the app and the more you iterate, the higher the usage. Blueprint Maker bills generation with a clear subscription: free Discovery plan, Pro at €25/month, Max at €149/month, with the credit cost shown before each generation, and no per-user counter on the delivered application.
Blueprint Maker and bolt.new head to head
| Blueprint Maker | bolt.new | |
|---|---|---|
| AI's role | AI writes the business specification; deterministic builders write the code | AI writes the application code directly, in conversation |
| Reproducibility | Same description = same code, by construction | Each iteration is a fresh generation, with its share of randomness |
| Bug fixing | Correct by construction: no fixing phase on the structure | A significant share of effort and token cost can go into fixing |
| Validation | Automated runtime validation (K-15): app built, started and browsed; public Health Score | Live in-browser preview, judged by eye along the conversation |
| Scope | A finished business management app: database, API, CRUD, dashboard, data | General-purpose and open: wide range of frameworks and app types |
| Data integrity | Computed fields, aggregates and business rules enforced deterministically | Depends on the code produced each turn, with no systematic guarantee |
| Code and hosting | Standard Next.js + Prisma, ZIP / GitHub export, FR/EU URL and database included | GitHub export and deploy (e.g. Netlify) from the browser |
| Cost model | Clear subscription (€0 / €25 / €149), credits shown before generation | Token consumption: rises with complexity and iterations |
When bolt.new is the right choice
- You want to prototype a full-stack idea very quickly, in the browser, with nothing to install.
- You're freely exploring a direction, an interactive demo or a landing page, with no constraints on form.
- You want the freedom to pick your framework from a wide range (React, Vue, Astro, etc.).
- You're a developer, comfortable taking over the code and debugging it yourself across iterations.
- The result is throwaway or experimental: reproducibility and strict integrity aren't the point.
When Blueprint Maker is the right choice
- You want a reliable business management application, not a prototype to debug.
- You don't want to pay, in time or in tokens, to fix the bugs of free-flowing code generation.
- You need data that doesn't lie: computed fields, aggregates and business rules consistent by construction.
- You want a reproducible result and a regular project structure, that a developer picks up without untangling a conversation history.
- You want to own standard Next.js + Prisma code, hosted in France / EU, database included.
Frequently asked questions: Blueprint Maker vs bolt.new
Do bolt.new and Blueprint Maker both use AI to write the application?
Yes, but not in the same place. bolt.new lets a model write the code directly, turn after turn, in conversation. Blueprint Maker has AI write only the business specification, the entities, relations, rules, and then deterministic builders, code we control, write the application. AI describes; it doesn't build the structure. That's what makes the result reproducible and correct by construction.
Why frame "bug fixing" as a stake?
Because it's a documented pain point of conversational code generation in general: a small change can break another, and fixing one bug can introduce a new one, so a significant share of the effort, and of the cost, when billing is by tokens, goes into fixing rather than creating. It's not a jab at any specific product: it's inherent to letting a model rewrite code on every turn. Blueprint Maker avoids that loop by validating the specification upstream and the runtime downstream (K-15).
What is K-15 validation, concretely?
Before delivering an application, Blueprint Maker actually builds it, starts it, and browses it automatically to check that screens render and work. It's our only automated quality criterion we deem reliable, and it feeds a public Health Score. A live in-browser preview shows the state of one moment; K-15 verifies that the application stands up once built for real.
Is Blueprint Maker less flexible than bolt.new?
On scope, yes, and that's by design. bolt.new is general-purpose: it produces a wide range of web applications across many frameworks, with great freedom of form. Blueprint Maker specializes in the business management application. That tight scope is precisely what allows determinism and integrity guarantees: you only guarantee by construction what you know how to build.
Can you get and evolve the code in both cases?
Yes. bolt.new allows GitHub export and deployment from the browser. Blueprint Maker exports standard Next.js + Prisma, as a ZIP or via GitHub push, with an FR/EU hosting URL and the database included. The nuance: Blueprint Maker's code comes out of a deterministic pipeline, so its structure is regular from one application to the next and can be picked up without untangling a conversation's history.