Exa Architecture Variants

Exa Architecture Variants

Prerequisites

• A defined use case, data/policy classification, owner, source/citation requirements, and fallback decision.
• A non-sensitive evaluation set and review for any automation or architecture change.

Output

• A documented architecture choice tied to retrieval quality, latency, cost, policy, ownership, and rollback implications.

Examples

Compare a direct-search and a review-gated retrieval architecture using sanitized evaluation queries, score citation support and latency, and record the selected variant plus fallback. Do not choose an autonomous action path without explicit policy controls and human review for consequential decisions.

Overview

Three deployment architectures for Exa neural search at different scales. Each uses real Exa SDK methods: search, searchAndContents, findSimilar, getContents, and answer.

Decision Matrix

Instructions

Variant 1: Direct Search Integration

Best for: Adding search to an existing app, < 1K queries/day.

import Exa from "exa-js";
import express from "express";

const app = express();
const exa = new Exa(process.env.EXA_API_KEY);

// Simple search endpoint
app.get("/api/search", async (req, res) => {
  const query = req.query.q as string;
  if (!query) return res.status(400).json({ error: "q required" });

  try {
    const results = await exa.searchAndContents(query, {
      type: "auto",
      numResults: 5,
      text: { maxCharacters: 500 },
      highlights: { maxCharacters: 300, query },
    });

    res.json(results.results.map(r => ({
      title: r.title,
      url: r.url,
      snippet: r.highlights?.join(" ") || r.text?.substring(0, 200),
      score: r.score,
    })));
  } catch (err: any) {
    res.status(err.status || 500).json({ error: err.message });
  }
});

Variant 2: Cached Search with Category Profiles

Best for: High-traffic search, 1K-50K queries/day, content discovery.

import Exa from "exa-js";
import { LRUCache } from "lru-cache";

const exa = new Exa(process.env.EXA_API_KEY);
const cache = new LRUCache<string, any>({ max: 5000, ttl: 3600 * 1000 });

const PROFILES = {
  news: {
    type: "auto" as const,
    category: "news" as const,
    numResults: 10,
    text: { maxCharacters: 500 },
  },
  research: {
    type: "neural" as const,
    category: "research paper" as const,
    numResults: 10,
    text: { maxCharacters: 2000 },
    highlights: { maxCharacters: 500 },
  },
  companies: {
    type: "auto" as const,
    category: "company" as const,
    numResults: 10,
    text: { maxCharacters: 500 },
  },
};

async function cachedProfileSearch(
  query: string,
  profile: keyof typeof PROFILES
) {
  const key = `${query.toLowerCase()}:${profile}`;
  const cached = cache.get(key);
  if (cached) return cached;

  const results = await exa.searchAndContents(query, PROFILES[profile]);
  cache.set(key, results);
  return results;
}

Variant 3: Full RAG Pipeline

Best for: AI-powered answers, research agents, 50K+ queries/day.

import Exa from "exa-js";
import { LRUCache } from "lru-cache";

const exa = new Exa(process.env.EXA_API_KEY);
const contextCache = new LRUCache<string, any>({ max: 10000, ttl: 7200 * 1000 });

class ExaRAGPipeline {
  // Phase 1: Search for relevant sources
  async gatherContext(question: string, maxSources = 5) {
    const cacheKey = question.toLowerCase().trim();
    const cached = contextCache.get(cacheKey);
    if (cached) return cached;

    const results = await exa.searchAndContents(question, {
      type: "neural",
      numResults: maxSources,
      text: { maxCharacters: 2000 },
      highlights: { maxCharacters: 500, query: question },
    });

    contextCache.set(cacheKey, results);
    return results;
  }

  // Phase 2: Expand with similar content
  async expandContext(topResultUrl: string, numSimilar = 3) {
    return exa.findSimilarAndContents(topResultUrl, {
      numResults: numSimilar,
      text: { maxCharacters: 1500 },
      excludeSourceDomain: true,
    });
  }

  // Phase 3: Format for LLM context injection
  formatForLLM(results: any[]) {
    return results.map((r, i) =>
      `[Source ${i + 1}] ${r.title}\n` +
      `URL: ${r.url}\n` +
      `Content: ${r.text}\n` +
      `Key points: ${r.highlights?.join(" | ") || "N/A"}`
    ).join("\n\n---\n\n");
  }

  // Phase 4: Use Exa's built-in answer endpoint
  async getAnswer(question: string) {
    const answer = await exa.answer(question, { text: true });
    return {
      answer: answer.answer,
      sources: answer.results.map(r => ({
        title: r.title,
        url: r.url,
      })),
    };
  }

  // Full pipeline
  async research(question: string) {
    const context = await this.gatherContext(question, 5);

    // Expand with similar content from top result
    let expanded = { results: [] as any[] };
    if (context.results[0]?.url) {
      expanded = await this.expandContext(context.results[0].url);
    }

    const allResults = [...context.results, ...expanded.results];
    const llmContext = this.formatForLLM(allResults);

    return {
      context: llmContext,
      sourceCount: allResults.length,
      sources: allResults.map(r => ({ title: r.title, url: r.url, score: r.score })),
    };
  }
}

Scaling Notes

Error Handling

Resources

• Exa API Documentation
• Exa Contents Retrieval
• Exa Find Similar

Next Steps

For reference architecture details, see exa-reference-architecture.