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Bassem Shahin
Bassem Shahin

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Migrating reCAPTCHA solving off 2Captcha: the one-line swap (and what changes at volume)

#webscraping #python #automation #captcha

Migrating reCAPTCHA solving off 2Captcha: the one-line swap

Most teams who solve reCAPTCHA at volume started on 2Captcha. What people don't realize is that the 2Captcha API has effectively become a shared interface — several providers implement the same in.php / res.php contract. So switching usually isn't a rewrite; it's a base-URL change.

This matters because the main reason to switch is cost at volume (per-1,000 scales linearly; thread-based flattens it). If migrating were a big refactor the savings wouldn't be worth it. It isn't, so they are.

The actual diff

Typical 2Captcha reCAPTCHA code:


import requests, time

API_KEY = "YOUR_KEY"

BASE = "https://2captcha.com"          # the only provider-specific line

submit = requests.get(f"{BASE}/in.php", params={

    "key": API_KEY, "method": "userrecaptcha",

    "googlekey": SITE_KEY, "pageurl": PAGE_URL})

task_id = submit.text.split("|")[1]

while True:

    r = requests.get(f"{BASE}/res.php", params={"key": API_KEY, "action": "get", "id": task_id})

    if r.text == "CAPCHA_NOT_READY": time.sleep(5); continue

    token = r.text.split("|")[1]; break
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Migrating to a 2Captcha-compatible provider:


BASE = "https://ocr.captchaai.com"     # changed

API_KEY = "YOUR_NEW_KEY"               # changed

# everything else is byte-for-byte identical
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method=userrecaptcha, googlekey, pageurl, the OK| response, CAPCHA_NOT_READY polling, the token — all the same. Wrapped it in a client class? Change one constant. Used an SDK? Point it at the new base URL.

What stays identical

  • The reCAPTCHA flow: v2 checkbox, v2 invisible, v3 version=v3 + min_score) — same call shape.

  • Token handling, your retry/timeout/polling logic — untouched.

What changes

  1. The pricing model (the point): per-1,000 → per-thread with unlimited solves. Size for peak concurrency, not monthly total.

  2. Latency / success-rate are provider-specific — so measure, don't assume.

How to migrate without betting the pipeline on it

  1. Keep 2Captcha wired in; add the new provider behind the same interface (same calls — trivial).

  2. Route ~10% of traffic to the new one.

  3. Compare on your targets: success rate, median latency, cost per 1,000.

  4. Holds up? Ramp. Doesn't? You've lost nothing.

Because the API is identical, that A/B harness is a few lines and a flag.

The honest version

A compatible provider is a drop-in at the API level — that part is a one-line swap. Whether it's the right swap depends on your numbers: run the A/B on real traffic and let the data decide. Compatibility just makes that test cheap.

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