Respan

Respan (formerly Keywords AI) is an LLM engineering platform for observability, evaluation, and gateway routing. Respan integrates with the AI SDK to provide:

Tracing for each AI SDK call (input, output, token usage, cost, latency)
Tool call and structured output capture
Optional gateway routing across 250+ models behind a single endpoint

Setup

The AI SDK supports tracing via OpenTelemetry. With the VercelAIInstrumentor from @respan/instrumentation-vercel, traces are exported to Respan automatically.

Install

npm install ai @ai-sdk/openai @respan/respan @respan/instrumentation-vercel

Configure environment variables

RESPAN_API_KEY="your-respan-api-key"

Get your API key from platform.respan.ai.

Initialize Respan

Next.js

Serverless / Node

Create instrumentation.ts at the root of your Next.js project:

import { Respan } from '@respan/respan';
import { VercelAIInstrumentor } from '@respan/instrumentation-vercel';

export async function register() {
  const respan = new Respan({
    apiKey: process.env.RESPAN_API_KEY,
    instrumentations: [new VercelAIInstrumentor()],
  });
  await respan.initialize();
}

Then mark the SDK packages as server-external in next.config.ts:

import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
  serverExternalPackages: ['@respan/respan', '@respan/instrumentation-vercel'],
};

export default nextConfig;

Initialize Respan at the top of your handler or entry point:

import { Respan } from '@respan/respan';
import { VercelAIInstrumentor } from '@respan/instrumentation-vercel';

const respan = new Respan({
  apiKey: process.env.RESPAN_API_KEY,
  instrumentations: [new VercelAIInstrumentor()],
});
await respan.initialize();

Next.jsServerless / Node

Create instrumentation.ts at the root of your Next.js project:

import { Respan } from '@respan/respan';
import { VercelAIInstrumentor } from '@respan/instrumentation-vercel';

export async function register() {
  const respan = new Respan({
    apiKey: process.env.RESPAN_API_KEY,
    instrumentations: [new VercelAIInstrumentor()],
  });
  await respan.initialize();
}

Then mark the SDK packages as server-external in next.config.ts:

import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
  serverExternalPackages: ['@respan/respan', '@respan/instrumentation-vercel'],
};

export default nextConfig;

Initialize Respan at the top of your handler or entry point:

import { Respan } from '@respan/respan';
import { VercelAIInstrumentor } from '@respan/instrumentation-vercel';

const respan = new Respan({
  apiKey: process.env.RESPAN_API_KEY,
  instrumentations: [new VercelAIInstrumentor()],
});
await respan.initialize();

Generate text with telemetry enabled

import { openai } from '@ai-sdk/openai';
import { generateText } from 'ai';

const result = await generateText({
  model: openai('gpt-6-luna'),
  prompt: 'Tell me a joke about AI',
  experimental_telemetry: { isEnabled: true },
});

Spans appear in the Respan traces page with input, output, token usage, and cost.

Gateway routing (optional)

To use Respan as a unified gateway across providers, point your AI SDK provider at the Respan gateway with your RESPAN_API_KEY. For the OpenAI provider, use https://api.respan.ai/api as the base URL. Provider keys are managed in Respan; only the Respan key is needed at runtime.

import { createOpenAI } from '@ai-sdk/openai';
import { generateText } from 'ai';

const provider = createOpenAI({
  apiKey: process.env.RESPAN_API_KEY!,
  baseURL: 'https://api.respan.ai/api',
});

const result = await generateText({
  model: provider('gpt-5.4-nano'),
  prompt: 'Tell me a joke about AI',
  experimental_telemetry: { isEnabled: true },
});

The same gateway endpoint accepts Anthropic and Google models when used with their respective AI SDK providers (createAnthropic, createGoogleGenerativeAI) and the matching base path (/api/anthropic, /api/google/gemini).