Instantly Rate Limits Skill

Instantly Rate Limits

Overview

Handle Instantly API v2 rate limits. The API returns 429 Too Many Requests when limits are exceeded. Most endpoints follow standard limits. The email listing endpoint has a stricter constraint of 20 requests per minute. Failed webhook deliveries are retried up to 3 times within 30 seconds.

Prerequisites

Completed instantly-install-auth setup
Understanding of exponential backoff patterns

Known Rate Limits

| Endpoint | Limit | Notes | |----------|-------|-------| | Most API endpoints | Standard REST limits | Varies by plan | | GET /emails | 20 req/min | Stricter — email listing | | Webhook deliveries | 3 retries in 30s | Instantly retries to your endpoint | | Background jobs | N/A | Async — poll via GET /background-jobs/{id} |

Instructions

Step 1: Exponential Backoff with Jitter

import { InstantlyApiError } from "./src/instantly/client";

interface RetryOptions {
  maxRetries: number;
  baseDelayMs: number;
  maxDelayMs: number;
}

const DEFAULT_RETRY: RetryOptions = {
  maxRetries: 5,
  baseDelayMs: 1000,
  maxDelayMs: 30000,
};

async function withBackoff<T>(
  operation: () => Promise<T>,
  opts: Partial<RetryOptions> = {}
): Promise<T> {
  const { maxRetries, baseDelayMs, maxDelayMs } = { ...DEFAULT_RETRY, ...opts };

  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    try {
      return await operation();
    } catch (err) {
      const isRetryable =
        err instanceof InstantlyApiError &&
        (err.status === 429 || err.status >= 500);

      if (!isRetryable || attempt === maxRetries) throw err;

      // Parse Retry-After header if available
      let delay = baseDelayMs * Math.pow(2, attempt);
      delay = Math.min(delay, maxDelayMs);

      // Add jitter (10-30% of delay)
      const jitter = delay * (0.1 + Math.random() * 0.2);
      const totalDelay = delay + jitter;

      console.warn(
        `Rate limited (attempt ${attempt + 1}/${maxRetries}). Waiting ${Math.round(totalDelay)}ms...`
      );
      await new Promise((r) => setTimeout(r, totalDelay));
    }
  }
  throw new Error("Unreachable");
}

Step 2: Request Queue with Concurrency Control

class RequestQueue {
  private queue: Array<() => Promise<void>> = [];
  private running = 0;
  private readonly maxConcurrent: number;
  private readonly delayBetweenMs: number;

  constructor(maxConcurrent = 5, delayBetweenMs = 200) {
    this.maxConcurrent = maxConcurrent;
    this.delayBetweenMs = delayBetweenMs;
  }

  async add<T>(operation: () => Promise<T>): Promise<T> {
    return new Promise((resolve, reject) => {
      this.queue.push(async () => {
        try {
          const result = await withBackoff(operation);
          resolve(result);
        } catch (err) {
          reject(err);
        } finally {
          this.running--;
          this.processQueue();
        }
      });
      this.processQueue();
    });
  }

  private async processQueue() {
    while (this.running < this.maxConcurrent && this.queue.length > 0) {
      const task = this.queue.shift()!;
      this.running++;
      if (this.delayBetweenMs > 0) {
        await new Promise((r) => setTimeout(r, this.delayBetweenMs));
      }
      task();
    }
  }
}

// Usage — add 500 leads with controlled concurrency
const queue = new RequestQueue(3, 300); // 3 concurrent, 300ms gap

for (const lead of leads) {
  queue.add(() =>
    instantly("/leads", {
      method: "POST",
      body: JSON.stringify({ campaign: campaignId, email: lead.email, ...lead }),
    })
  );
}

Step 3: Rate-Limited Email Listing

// The /emails endpoint has a 20 req/min limit
// Use a dedicated throttled fetcher
class ThrottledEmailFetcher {
  private requestTimestamps: number[] = [];
  private readonly maxPerMinute = 18; // leave 2 req margin

  private async waitForSlot() {
    const now = Date.now();
    this.requestTimestamps = this.requestTimestamps.filter(
      (t) => now - t < 60000
    );

    if (this.requestTimestamps.length >= this.maxPerMinute) {
      const oldest = this.requestTimestamps[0];
      const waitMs = 60000 - (now - oldest) + 1000; // +1s buffer
      console.log(`Email API throttle: waiting ${waitMs}ms`);
      await new Promise((r) => setTimeout(r, waitMs));
    }

    this.requestTimestamps.push(Date.now());
  }

  async listEmails(params: {
    campaign_id?: string;
    is_unread?: boolean;
    limit?: number;
    starting_after?: string;
  }) {
    await this.waitForSlot();

    const qs = new URLSearchParams();
    if (params.campaign_id) qs.set("campaign_id", params.campaign_id);
    if (params.is_unread !== undefined) qs.set("is_unread", String(params.is_unread));
    if (params.limit) qs.set("limit", String(params.limit));
    if (params.starting_after) qs.set("starting_after", params.starting_after);

    return instantly(`/emails?${qs}`);
  }
}

Step 4: Batch Operations Pattern

// Instead of creating leads one-by-one, batch where possible
async function addLeadsBatched(
  campaignId: string,
  leads: Array<{ email: string; first_name?: string }>,
  batchSize = 10,
  delayBetweenBatchesMs = 1000
) {
  let added = 0;
  let failed = 0;

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

    const results = await Promise.allSettled(
      batch.map((lead) =>
        withBackoff(() =>
          instantly("/leads", {
            method: "POST",
            body: JSON.stringify({
              campaign: campaignId,
              email: lead.email,
              first_name: lead.first_name,
              skip_if_in_workspace: true,
            }),
          })
        )
      )
    );

    added += results.filter((r) => r.status === "fulfilled").length;
    failed += results.filter((r) => r.status === "rejected").length;

    console.log(`Batch ${Math.floor(i / batchSize) + 1}: ${added} added, ${failed} failed`);

    if (i + batchSize < leads.length) {
      await new Promise((r) => setTimeout(r, delayBetweenBatchesMs));
    }
  }

  console.log(`\nTotal: ${added} added, ${failed} failed out of ${leads.length}`);
}

Error Handling

| Error | Cause | Solution | |-------|-------|----------| | 429 on lead import | Too many sequential POSTs | Use batch pattern with delays | | 429 on email listing | >20 req/min | Use ThrottledEmailFetcher | | 5xx intermittent | Instantly server overload | Backoff + retry; check status.instantly.ai | | Webhook delivery retries exhausted | Your endpoint too slow | Return 200 immediately, process async | | Queue memory growing | Too many queued operations | Set max queue size, reject overflow |

Resources

Next Steps

For security patterns, see instantly-security-basics.

Agent Skills: Instantly Rate Limits

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