A 62KB login plugin got 4,000 users from one line of link in an account-reseller's after-sales tutorial

Claude Session Login is a free Chrome extension that does one thing: writes a Claude sessionKey into claude.ai's cookies so you can log in without email or password. It has been listed for almost five months and had 4,000 users as of Nov 6. Nothing about it is special, and the store already has three extensions with the same name. It took off because a Chinese reseller put it in its "must-read after purchase" guide.

"After purchase we only send the SK"

On 2026 Jul at 3 6:30 pm, the account-selling site CZGPT (czgptai.com, which sells finished ChatGPT, Claude, Gemini and Grok accounts plus top-up services) published a post on its blog titled "Claude Account Login Guide 2026 July New Version: Must-Read Before Buying." Mid-article there's a subheading: "Why do we now only send the SK (SessionKey) after purchase?" The reason given: "Anthropic has started embedding 'trackers' in emails sent to users to locate their real region," so "to protect your account, we only send the SK after purchase."

The next section, "Install the SessionKey login extension," opens with a Chrome Web Store link to this exact extension and tells buyers to open it in Chrome "under a US IP." Install it, open it, paste the SK from the delivery message, and you're logged in. For buyers who only use Claude Code, it's the same: log in the browser with the extension and SK first, then paste the authorization link from the terminal's /login into that same browser.

The same post says: "If you run into problems, don't contact customer service, we won't respond." The guide is the entire after-sale support, so buyers just follow the steps. Every account sold adds one install to the store.

What it is

A 62KB extension with only cookies, storage and claude.ai permissions. The UI lets you "+ add" several sessionKeys and switch between accounts with one click (per CZGPT's guide). The privacy policy is a single Chinese-language Notion page saying SKs are stored in browser sync storage and only claude.ai cookies are written.

The store listing has the feel of bulk publishing: the developer display name is a string of numbers "7201237", the contact is a personal Gmail, there's no website, and the listing was machine-translated into 55 languages, with Swahili set as the primary language. Listed 16 Jun 1.0.1, never updated since.

More telling: the same developer listed another extension, "Claude SK Extraction", 5 minutes before this one. It copies the SK from a logged-in browser in one click. One extension extracts for sellers, one writes for buyers, listed as a pair. The extraction one has 57 users and this one 4,000, which fits "few sellers, many buyers."

Where the 4,000 users came from

Chrome Web Store, 11-01 to 11-06. 4,000 users but only 1 ratings, which suggests people didn't discover it by browsing the store. They were sent there, installed it, and went on with their task.

Three traffic sources, each traceable to a post:

One: the reseller guide, the main channel. The CZGPT "must-read after purchase" above. CZGPT's homepage claims it has "helped 100k+ users." The number can't be verified, but selling a few hundred Claude accounts a month would be enough to produce this curve (inference).

Two: forum advertorials. On NodeSeek in Oct 27 and sb.sb in Oct 31, posts titled "Sharing a safe Claude environment setup and check (with SK passwordless login…)" carry this extension's link in a "supplement" section. The images match CZGPT's blog, same image host, same files. The same operator is almost certainly behind both.

Three: SEO sites. In Oct 28, a content site on a Japanese domain published an English tutorial, "Claude Web Login Without Password: SessionKey Setup Guide," calling it the "official Claude Session Login extension."

The jump from 3,000 to 4,000 in Nov 6 lines up with these October posts. On the same day, a same-name extension in the Russian-language market also went from 2,000 to 3,000, so part of this may be broader demand for buying Claude accounts. No ads seen, and nobody has discussed it on X in the last 90 days.

Why this moment

From late June to early July, Sina Finance (Jul 1), Zhihu, Sohu and cnblogs all ran a cluster of articles claiming Anthropic embeds trackers in ban and verification emails to locate real regions. Resellers used this to switch delivery from "account + password + email" to "SK only," arguing that never touching email is safest.

The extension was listed in Jun 16, and the story arrived two weeks later, timed right. The old standard reseller guide had buyers install Cookie-Editor and manually create a cookie named sessionKey, which had many steps and was easy to get wrong. A dedicated extension cut that down to paste and confirm.

Who it's competing with

There are also Tampermonkey script versions, several open-source GitHub builds you have to unzip and load, and mirror sites where you type in the SK directly. The code is under a hundred lines, and anyone can write it. What decides who gets the users is one thing: which link the seller's guide pastes.

Where the money comes from

The extension itself costs nothing. No in-app purchases, no website. The money is in the account sale: online prices for finished accounts and top-ups are roughly ¥180–230 for Pro, ¥800-900 for Max 5x, and ¥1,600-1,700 for Max 20x (per aichongzhi.org and dgtsell.com listings). Taobao has a large pool of "Claude Max dedicated finished accounts" too. The extension is just the last mile of this business.

The risks are clearly visible too. Anthropic's terms prohibit reselling accounts and using them from unsupported regions. In Aug 29, Anthropic logged out a batch of users over stolen sessions. If the platform runs another crackdown, or the Chrome Web Store removes it under policy, extensions like this vanish overnight.

If it were you

D: know about it, but I wouldn't follow it. Its users all come from reseller guides, so a follower can't get that channel unless you already sell accounts. The feature is zero-barrier and three same-name copies already exist. The whole thing sits in a grey zone under Anthropic's terms and store policies, and the platform could cut it off at any time.

Who it fits: people already in account resale, top-ups or shared-account businesses who have sales volume. For them, a login extension they control, written into the after-sale guide, is an easy add.

Who it doesn't fit: indie developers hoping one extension will bring them volume on its own. Without a seller's guide behind it, these extensions look identical in store search and make no money. It's especially wrong for anyone who doesn't want to touch grey-area account resale.

What's actually worth taking away: make the extension part of the delivery flow. Any business where the customer must take one step after paying, such as provisioning a SaaS account, inviting members to a team plan, or unlocking a course platform, can build that step as its own extension and put it in the post-purchase instructions. Every order brings one install, the store search term gets claimed as a side effect, and users rarely have a reason to uninstall. This is a playbook a legitimate business can copy.

How to get users: don't rely on store search, rely on sales. Put the extension link in delivery messages, after-sale guides and support scripts. Reuse the guide on forums and SEO sites with consistent visuals so you don't rewrite each post.

When was the window: this one is already past its window. For similar extensions in the grey zone, the window depends on when the platform acts, and nobody can say when that will be.

What would show I got it wrong: ① it grew by 10k by itself before year-end without new guides being pushed, which would mean store search alone can drive volume and the bar for a similar extension is lower than it looks; ② someone openly publishes that using an extension as a real SaaS delivery step produced a clear lift in activation, which would make this playbook more worth doing than described here; ③ conversely, if Anthropic or the Chrome Web Store removes this category of extension in bulk before early next year, even "know about it" won't be needed.

Data and sources

• Store page: chromewebstore.google.com/detail/claude-session-login/djmnahhenbfgbepcgdkofpgnaangeohc. User counts and rating counts from 11-01 to 11-06 come from daily Chrome Web Store scrapes. The companion extraction tool, same-name extensions and competitor data are also from the Chrome Web Store, around 11-06.
• CZGPT after-sale guide: czgptai.com/blog/claude-account-login-guide-2026-07 (published 2026-07-03, read 11-06).
• Forum posts: nodeseek.com/post-1012906-1 (2026-10-27), sb.sb/t/15286 (2026-10-31); SEO site: aijp.jizhiku.net/archives/25235 (2026-10-28).
• "Email tracker" coverage: Sina Finance 2026-07-01, Zhihu columns, and others.
• Prices: the Claude category pages on aichongzhi.org and dgtsell.com.
• Old manual guides: linux.do/t/topic/75390, Juejin.
• Discussion on X: keyword search over the last 90 days, no relevant content.