技能 编程开发 API速率限制与重试机制

API速率限制与重试机制

v20260423
exa-rate-limits
本指南详细介绍了如何在代码层面对外部API进行健壮的限速控制和错误恢复。内容涵盖了指数退避(Exponential Backoff)、随机抖动(Jitter)和请求队列等高级技术,帮助开发者确保在高并发、速率受限的环境下API调用依然稳定可靠。
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Exa Rate Limits

Overview

Handle Exa API rate limits gracefully. Default limit is 10 QPS (queries per second) across all endpoints. Rate limit errors return HTTP 429 with a simple { "error": "rate limit exceeded" } response. For higher limits, contact hello@exa.ai for Enterprise plans.

Rate Limit Structure

Endpoint Default QPS Notes
/search 10 Most endpoints share this limit
/find-similar 10 Same pool as search
/contents 10 Same pool
/answer 10 Same pool
Research API Concurrent task limit Long-running operations

Prerequisites

  • exa-js SDK installed
  • Understanding of async/await patterns

Instructions

Step 1: Exponential Backoff with Jitter

import Exa from "exa-js";

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

async function withBackoff<T>(
  operation: () => Promise<T>,
  config = { maxRetries: 5, baseDelayMs: 1000, maxDelayMs: 32000 }
): Promise<T> {
  for (let attempt = 0; attempt <= config.maxRetries; attempt++) {
    try {
      return await operation();
    } catch (err: any) {
      const status = err.status || err.response?.status;
      // Only retry on 429 (rate limit) and 5xx (server errors)
      if (status !== 429 && (status < 500 || status >= 600)) throw err;
      if (attempt === config.maxRetries) throw err;

      // Exponential delay with random jitter to prevent thundering herd
      const exponentialDelay = config.baseDelayMs * Math.pow(2, attempt);
      const jitter = Math.random() * 500;
      const delay = Math.min(exponentialDelay + jitter, config.maxDelayMs);

      console.log(`[Exa] ${status} — retry ${attempt + 1}/${config.maxRetries} in ${delay.toFixed(0)}ms`);
      await new Promise(r => setTimeout(r, delay));
    }
  }
  throw new Error("Unreachable");
}

// Usage
const results = await withBackoff(() =>
  exa.searchAndContents("AI research", { numResults: 5, text: true })
);

Step 2: Request Queue with Concurrency Control

import PQueue from "p-queue";

// Limit to 8 concurrent requests (under the 10 QPS limit)
const exaQueue = new PQueue({
  concurrency: 8,
  interval: 1000,    // per second
  intervalCap: 10,   // max 10 per interval (matches Exa's QPS limit)
});

async function queuedSearch(query: string, opts: any = {}) {
  return exaQueue.add(() => exa.searchAndContents(query, opts));
}

// Batch many queries safely
async function batchSearch(queries: string[]) {
  const results = await Promise.all(
    queries.map(q => queuedSearch(q, { numResults: 5, text: true }))
  );
  return results;
}

Step 3: Adaptive Rate Limiter

class AdaptiveRateLimiter {
  private currentDelay = 100; // ms between requests
  private minDelay = 50;
  private maxDelay = 5000;
  private consecutiveSuccesses = 0;
  private lastRequestTime = 0;

  async execute<T>(fn: () => Promise<T>): Promise<T> {
    const now = Date.now();
    const elapsed = now - this.lastRequestTime;
    if (elapsed < this.currentDelay) {
      await new Promise(r => setTimeout(r, this.currentDelay - elapsed));
    }

    try {
      this.lastRequestTime = Date.now();
      const result = await fn();
      this.consecutiveSuccesses++;

      // Speed up after 10 consecutive successes
      if (this.consecutiveSuccesses >= 10) {
        this.currentDelay = Math.max(this.minDelay, this.currentDelay * 0.8);
        this.consecutiveSuccesses = 0;
      }
      return result;
    } catch (err: any) {
      if (err.status === 429) {
        // Slow down on rate limit
        this.currentDelay = Math.min(this.maxDelay, this.currentDelay * 2);
        this.consecutiveSuccesses = 0;
        console.log(`[Exa] Rate limited. New delay: ${this.currentDelay}ms`);
      }
      throw err;
    }
  }
}

const limiter = new AdaptiveRateLimiter();

// Combine with backoff
const results = await withBackoff(() =>
  limiter.execute(() => exa.search("query", { numResults: 5 }))
);

Step 4: Batch Processing with Rate Awareness

async function processBatch(
  queries: string[],
  batchSize = 5,
  delayBetweenBatches = 1000
) {
  const allResults = [];

  for (let i = 0; i < queries.length; i += batchSize) {
    const batch = queries.slice(i, i + batchSize);

    // Process batch concurrently
    const batchResults = await Promise.all(
      batch.map(q => withBackoff(() =>
        exa.searchAndContents(q, { numResults: 3, text: true })
      ))
    );
    allResults.push(...batchResults);

    // Pause between batches to stay under rate limit
    if (i + batchSize < queries.length) {
      await new Promise(r => setTimeout(r, delayBetweenBatches));
    }

    console.log(`Processed ${Math.min(i + batchSize, queries.length)}/${queries.length}`);
  }

  return allResults;
}

Error Handling

Issue Cause Solution
429 errors Exceeding 10 QPS Implement backoff + queue
Burst rejected Too many simultaneous requests Use p-queue with intervalCap
Batch job failures No delay between batches Add delayBetweenBatches
Inconsistent throttling No jitter in retry Add random jitter to prevent thundering herd

Examples

Simple Retry Wrapper

async function retrySearch(query: string, maxRetries = 3) {
  for (let i = 0; i <= maxRetries; i++) {
    try {
      return await exa.search(query, { numResults: 5 });
    } catch (err: any) {
      if (err.status !== 429 || i === maxRetries) throw err;
      await new Promise(r => setTimeout(r, 1000 * Math.pow(2, i)));
    }
  }
}

Resources

Next Steps

For security configuration, see exa-security-basics.

信息
Category 编程开发
Name exa-rate-limits
版本 v20260423
大小 6.2KB
更新时间 2026-04-28
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