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Next.js belongs to the same runtime contract, but it should still feel native to its own request boundary.
Proxy and route-handler protection for App Router and middleware-heavy request paths. Choose the wrapper when the framework owns route resolution, hooks, loaders, or middleware order. The page should help you choose this surface deliberately, compare it against its lane neighbors, and keep operator proof in reach while you wire the integration.
lane family
7
App framework
package line
1
@cosantoir/next
contract vars
3
Shared across wrappers and native SDKs
operator lanes
2
Plus 2 native package families
Surface fit
Choose this surface when the boundary is real, not convenient.
A better docs system tells you why this lane exists, what makes it distinct, and how it hands off to the rest of the platform.
Use this when
Choose the wrapper when the framework owns route resolution, hooks, loaders, or middleware order.
Package line
@cosantoir/next
The install and contract line should stay recognizable even when the request lifecycle changes.
First proof
Protect one real route, loader, or handler first, then read the resulting headers and decision state before broadening the rollout.
Install line
Next.js package install
01pnpm add @cosantoir/next @cosantoir/nodeShared contract
Runtime identity
01COSANTOIR_GATEWAY_URL=http://localhost:400002COSANTOIR_API_KEY=dp_live_example03COSANTOIR_SITE_ID=site_prod_webContract discipline
The framework changes. The contract should not.
This is the point where the left rail, page body, and right rail need to agree: the package can change, but the gateway origin, runtime key, site id, and proof loop stay the same.
01
COSANTOIR_GATEWAY_URL
Keep this value aligned across application middleware, direct SDK probes, and operator tooling so the same request path stays explainable.
02
COSANTOIR_API_KEY
Keep this value aligned across application middleware, direct SDK probes, and operator tooling so the same request path stays explainable.
03
COSANTOIR_SITE_ID
Keep this value aligned across application middleware, direct SDK probes, and operator tooling so the same request path stays explainable.
Lane neighbors
Neighbor surfaces
A mature docs system makes adjacent choices visible. If this page is not the right boundary, the best alternative should already be in front of you.
App framework
Astro
SSR middleware entry point for Astro request handling.
App framework
Nuxt
Server middleware surface for Nuxt application routes.
App framework
SvelteKit
Hook-based enforcement for SvelteKit routes and endpoints.
App framework
SolidStart
Middleware surface for SolidStart request handling.
App framework
Remix
Loader and action control for Remix applications.
App framework
React Router
Data-router protection for route loaders and actions.
Handoff
Node.js
Direct evaluator client for custom servers, bespoke middleware order, and exact transport control.
Handoff
CLI
Terminal lane for login, request probes, and telemetry-backed operator workflows.
Handoff
MCP
Model-facing tool server for safe policy and evaluator access.
Launch route
Quickstart
Wire a first protected request and stop only when the receipt is explainable.
Control map
Architecture
Trace how the wrapper, gateway, evaluator, and dashboard stay on the same contract line.
Operator lane
CLI
Bootstrap credentials, run probes, and inspect runtime decisions without leaving the terminal.
Agent lane
MCP
Expose bounded runtime tools to model workflows without widening system reach.
Detailed guide
Next.js page guide
The framework-specific instructions live below, but they now sit inside a stronger system: lane fit above, contract line beside, neighbors nearby.
# Next.js Integration
Cosantoir ships a dedicated Next.js middleware adapter with request IP helpers and route-handler context builders.
## Installation
``bash
npm install @cosantoir/next @cosantoir/node
`
## Middleware Example
Create middleware.ts in your Next.js root:
`ts
import { createCosantoir } from '@cosantoir/node';
import { createMiddleware, readNextRequestIp } from '@cosantoir/next';
const client = createCosantoir({
baseUrl: process.env.COSANTOIR_GATEWAY_URL!,
apiKey: process.env.COSANTOIR_API_KEY!,
siteId: process.env.COSANTOIR_SITE_ID!,
});
export const middleware = createMiddleware({
client,
failOpen: true,
ip: (request) => readNextRequestIp(request as any) ?? '127.0.0.1',
});
export const config = {
matcher: ['/api/:path*'],
};
`
## Route Handler Pattern
Use the same client inside Route Handlers when you need direct WAF, bot, or signup decisions.
`ts
export async function GET(request: Request) {
const ip = request.headers.get('x-forwarded-for') ?? '127.0.0.1';
const waf = await client.waf.evaluate({
ip,
method: request.method,
path: new URL(request.url).pathname,
});
if (waf.result?.action === 'block') {
return new Response('Forbidden', { status: 403 });
}
return new Response('Secure next route');
}
``