Firecrawl reliability patterns

Firecrawl Reliability Patterns

Overview

Production reliability patterns for Firecrawl scraping pipelines. Firecrawl's async crawl model, JS rendering, and credit-based pricing create specific reliability challenges: crawl jobs may time out, scraped content may be empty (bot detection, JS failures), and credits can be burned by runaway crawls. This skill covers battle-tested patterns for each.

Instructions

Step 1: Robust Crawl with Timeout and Backoff

import FirecrawlApp from "@mendable/firecrawl-js";

const firecrawl = new FirecrawlApp({
  apiKey: process.env.FIRECRAWL_API_KEY!,
});

async function reliableCrawl(
  url: string,
  opts: { limit: number; paths?: string[] },
  timeoutMs = 600000
) {
  const job = await firecrawl.asyncCrawlUrl(url, {
    limit: opts.limit,
    includePaths: opts.paths,
    scrapeOptions: { formats: ["markdown"], onlyMainContent: true },
  });

  const deadline = Date.now() + timeoutMs;
  let pollInterval = 2000;

  while (Date.now() < deadline) {
    const status = await firecrawl.checkCrawlStatus(job.id);

    if (status.status === "completed") return status;
    if (status.status === "failed") {
      throw new Error(`Crawl failed: ${status.error}`);
    }

    await new Promise(r => setTimeout(r, pollInterval));
    pollInterval = Math.min(pollInterval * 1.5, 30000); // back off to 30s max
  }

  throw new Error(`Crawl timed out after ${timeoutMs}ms (job: ${job.id})`);
}

Step 2: Content Quality Validation

interface ScrapedPage {
  url: string;
  markdown: string;
  metadata: { title?: string; statusCode?: number };
}

function validateContent(page: ScrapedPage): {
  valid: boolean;
  reason?: string;
} {
  if (!page.markdown || page.markdown.length < 100) {
    return { valid: false, reason: "Content too short" };
  }

  if (page.metadata.statusCode && page.metadata.statusCode >= 400) {
    return { valid: false, reason: `HTTP ${page.metadata.statusCode}` };
  }

  const errorPatterns = [
    "access denied", "403 forbidden", "page not found",
    "captcha", "please verify", "enable javascript",
  ];
  const lower = page.markdown.toLowerCase();
  for (const pattern of errorPatterns) {
    if (lower.includes(pattern)) {
      return { valid: false, reason: `Error page detected: "${pattern}"` };
    }
  }

  return { valid: true };
}

Step 3: Crawl-to-Scrape Fallback

// If a full crawl fails, fall back to scraping critical pages individually
async function resilientFetch(urls: string[]): Promise<any[]> {
  // Try batch scrape first (most efficient)
  try {
    const batch = await firecrawl.batchScrapeUrls(urls, {
      formats: ["markdown"],
      onlyMainContent: true,
    });

    const results = (batch.data || []).filter(page => {
      const { valid } = validateContent({
        url: page.metadata?.sourceURL || "",
        markdown: page.markdown || "",
        metadata: page.metadata || {},
      });
      return valid;
    });

    if (results.length >= urls.length * 0.5) {
      return results; // batch succeeded (>50% valid)
    }
  } catch (batchError) {
    console.warn("Batch scrape failed, falling back to individual scrapes");
  }

  // Fallback: scrape individually with retries
  const results: any[] = [];
  for (const url of urls) {
    try {
      const result = await firecrawl.scrapeUrl(url, {
        formats: ["markdown"],
        onlyMainContent: true,
        waitFor: 5000,
      });
      if (validateContent({ url, markdown: result.markdown || "", metadata: result.metadata || {} }).valid) {
        results.push(result);
      }
    } catch (e) {
      console.error(`Failed to scrape ${url}: ${(e as Error).message}`);
    }
    // Delay between individual scrapes to avoid rate limits
    await new Promise(r => setTimeout(r, 1000));
  }

  return results;
}

Step 4: Circuit Breaker for Firecrawl

class FirecrawlCircuitBreaker {
  private failures = 0;
  private lastFailure = 0;
  private state: "closed" | "open" | "half-open" = "closed";
  private threshold: number;
  private resetTimeMs: number;

  constructor(threshold = 5, resetTimeMs = 60000) {
    this.threshold = threshold;
    this.resetTimeMs = resetTimeMs;
  }

  async execute<T>(operation: () => Promise<T>, fallback?: () => T): Promise<T> {
    // Check if circuit should reset
    if (this.state === "open" && Date.now() - this.lastFailure > this.resetTimeMs) {
      this.state = "half-open";
    }

    if (this.state === "open") {
      console.warn("Circuit breaker OPEN — using fallback");
      if (fallback) return fallback();
      throw new Error("Firecrawl circuit breaker is open");
    }

    try {
      const result = await operation();
      if (this.state === "half-open") {
        this.state = "closed";
        this.failures = 0;
      }
      return result;
    } catch (error) {
      this.failures++;
      this.lastFailure = Date.now();
      if (this.failures >= this.threshold) {
        this.state = "open";
        console.error(`Circuit breaker OPENED after ${this.failures} failures`);
      }
      throw error;
    }
  }
}

const breaker = new FirecrawlCircuitBreaker(5, 60000);

async function protectedScrape(url: string) {
  return breaker.execute(
    () => firecrawl.scrapeUrl(url, { formats: ["markdown"] }),
    () => ({ markdown: getCachedContent(url), metadata: { fromCache: true } })
  );
}

Step 5: Credit-Aware Processing

class CreditGuard {
  private dailyUsage = new Map<string, number>();
  private dailyLimit: number;

  constructor(dailyLimit = 5000) {
    this.dailyLimit = dailyLimit;
  }

  canAfford(credits: number): boolean {
    const today = new Date().toISOString().split("T")[0];
    return (this.dailyUsage.get(today) || 0) + credits <= this.dailyLimit;
  }

  record(credits: number) {
    const today = new Date().toISOString().split("T")[0];
    this.dailyUsage.set(today, (this.dailyUsage.get(today) || 0) + credits);
  }

  remaining(): number {
    const today = new Date().toISOString().split("T")[0];
    return this.dailyLimit - (this.dailyUsage.get(today) || 0);
  }
}

const creditGuard = new CreditGuard(5000);

async function budgetedCrawl(url: string, limit: number) {
  if (!creditGuard.canAfford(limit)) {
    throw new Error(`Budget exceeded: ${creditGuard.remaining()} credits remaining`);
  }

  const result = await reliableCrawl(url, { limit });
  creditGuard.record(result.data?.length || 0);
  return result;
}

Error Handling

Issue	Cause	Solution
Crawl timeout	Large site, slow rendering	Set timeout, reduce limit
Empty markdown	Bot detection or JS failure	Increase waitFor, use actions
Credit overrun	No budget tracking	Implement credit guard
Cascade failures	Single scrape failure crashes pipeline	Circuit breaker + fallback
Partial crawl results	Some pages blocked	Validate content, retry failed URLs

Examples

Full Resilient Pipeline

async function resilientPipeline(url: string) {
  const map = await firecrawl.mapUrl(url);
  const urls = (map.links || []).filter(u => u.includes("/docs/")).slice(0, 50);

  if (!creditGuard.canAfford(urls.length)) {
    console.warn("Budget tight — reducing scope");
    urls.splice(20); // trim to 20
  }

  const pages = await resilientFetch(urls);
  const valid = pages.filter(p => validateContent(p).valid);
  creditGuard.record(urls.length);

  return { scraped: urls.length, valid: valid.length, remaining: creditGuard.remaining() };
}

Resources

• Firecrawl API Reference
• Firecrawl Rate Limits

Next Steps

For policy enforcement, see firecrawl-policy-guardrails.