Jev and AI SDK Template by Vercel Labs

Vercel Labs released the Jev and AI SDK Template, an open-source Next.js 16 and React 19 form-routing starter that uses the typesafe-ai/jev model to route submissions and falls back to openai/gpt-5.6-luna-fast when Jev's confidence is below 95% or its evaluation fails. The template ships three example forms — /leads, /contact, and /issues — built on AI SDK 7, the Vercel AI Gateway, shadcn/ui, Base UI, Tailwind CSS 4, React Email, and Resend, and requires Node.js 22+ and pnpm. Routing a submission makes live model calls requiring AI Gateway access to both models, via an AI_GATEWAY_API_KEY or Vercel OIDC authentication.

Three forms use Jev https://vercel.com/i/what-is-jev to route submissions by context, with openai/gpt-5.6-luna-fast handling uncertain or failed evaluations. Includes editable samples, routing details, and optional email delivery. | Technology | Purpose | |---|---| | Next.js 16 and React 19 | App Router, shared form UI, and Server Actions | | AI SDK 7 and Vercel AI Gateway | Typed model calls and provider access | | shadcn/ui, Base UI, and Tailwind CSS 4 | Components and styling | | React Email and Resend | Email previews and optional delivery | - Node.js 22+ - pnpm package manager git clone https://github.com/vercel-labs/jev-ai-sdk-form-router.git cd jev-ai-sdk-form-router pnpm install Routing a submission, including a sample, makes live model calls and requires AI Gateway access to both typesafe-ai/jev and openai/gpt-5.6-luna-fast . Choose one of the authentication options below, or skip this step to explore the forms and load sample inputs without generating routing results. API Key Copy the environment example: cp .env.example .env.local Create a Vercel AI Gateway key https://vercel.com/d?to=%2F%5Bteam%5D%2F~%2Fai-gateway%2Fapi-keys and set AI GATEWAY API KEY in .env.local . Vercel OIDC Vercel deployments use automatic OIDC authentication through the SDK, without an API key. To use OIDC locally, install the Vercel CLI if needed, then link the project and pull its environment variables: npm install --global vercel vercel link vercel env pull .env.local pnpm dev Open localhost:3000 http://localhost:3000 . The home page redirects to /leads . | Example | Route | Routes to | |---|---|---| | Lead | /leads | Startup, growth, enterprise, or sales teams | | Contact | /contact | Billing, support, or general inquiries | | Issue Report | /issues | Frontend, platform, infrastructure, identity, or engineering teams | 1. Zod validates the submission against the fields in lib/examples.ts https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/lib/examples.ts . 2. Jev evaluates the complete submission using AI SDK’s experimental evaluate and selects an allowed team/specialty combination. 3. The app accepts Jev’s choice when its confidence is at least 95% . 4. If confidence is lower, missing, or invalid, or Jev fails, openai/gpt-5.6-luna-fast independently evaluates the same submission and criteria using generateText and Output.object . Its choice becomes final. 5. The result includes the destination, deciding model, Jev statistics, model timings, and an email preview. Confidence and selected-option probability are separate metrics. The threshold uses the unrounded value of providerMetadata.typesafe.confidence.destination . Jev’s displayed statistics remain attached to its original evaluation when the fallback model makes the final decision. Provider calls have bounded timeouts and one transient retry. If both models fail, the app returns a retryable error and sends no email. Optional email delivery Set up Resend through Vercel Marketplace The Resend Marketplace integration https://resend.com/docs/guides/vercel-marketplace-integration creates a Resend account and connects it to your Vercel project. During setup, you can select an existing Vercel domain or purchase one. 1. If you haven't already, install the Vercel CLI and link the project: npm install --global vercel vercel link 2. Start the integration setup: vercel i resend 3. Select an existing domain or purchase one through Vercel, then choose a plan and connect your project. Complete onboarding in Resend, choose Auto configure to add the DNS records, and wait for domain verification. 4. Pull the integration's environment variables for local development: vercel env pull .env.local 5. Confirm RESEND API KEY is present and set RESEND FROM in .env.local to a sender address on your verified domain. If you already have a Resend account, you can instead set RESEND API KEY and RESEND FROM directly using your existing API key and a verified domain https://resend.com/docs/dashboard/domains/introduction . Configure receiving inboxes In lib/recipients.ts https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/lib/recipients.ts , replace null with a valid inbox for every destination on the form you want to enable. Multiple destinations can share an inbox. An unchecked Email the receiving team checkbox appears on configured forms. Recipient keys are derived from the destination registry and checked by TypeScript. Addresses stay server-side. The validated submitter email becomes replyTo . Forms with unconfigured inboxes continue to provide previews. Email failures preserve the routing result. Resend acceptance does not confirm inbox delivery. If a connection drops after an opted-in submission, check Resend before resubmitting. | File | What to change | |---|---| | lib/examples.ts https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/lib/examples.ts | Form fields, samples, destinations, and routing criteria | | lib/router.ts https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/lib/router.ts | Models, confidence threshold, timeouts, and fallback policy | | lib/recipients.ts https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/lib/recipients.ts | Receiving inboxes | | lib/submission.ts https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/lib/submission.ts | Validation, email rendering, and delivery workflow | | components/router-form.tsx https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/components/router-form.tsx and components/routing-result.tsx https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/components/routing-result.tsx | Shared form and result UI | | emails/routed-submission.tsx https://github.com/vercel-labs/jev-ai-sdk-form-router/blob/main/emails/routed-submission.tsx | Email design | Keep the experimental AI SDK version pinned and rerun the checks when upgrading it. pnpm fix Format and apply lint fixes pnpm validate Lint, type check, Knip, and tests pnpm build Production build Tests mock the model providers and Resend. They make no external calls. Coverage includes confidence thresholds, fallback decisions, validation, recipient configuration, and delivery retries.