Letterhawk Privacy Policy
Effective November 9, 2026
Letterhawk is operated by Hall House Labs LLC, a North Carolina limited liability company. This policy describes the data the Letterhawk Chrome extension and its service collect, how we use it, and your choices.
Who this applies to
This policy covers two groups. Senders install Letterhawk and choose which outbound Gmail messages to track. Recipients receive those messages and do not have Letterhawk accounts. A tracked message contains a 1×1 image. When a recipient's mail app or a mail proxy loads it, Letterhawk records the open event described below for the sender. For recipients' data, Hall House Labs LLC acts on the sender's behalf. The sender decides whom to track and is responsible for any notice or consent the recipient's law requires.
If you received a tracked email
You can stop tracking pixels by turning off automatic image loading in your mail app, or by asking the sender to add you to their do-not-track list. To ask what Letterhawk holds about your email address, or to have it deleted, email german@hallhouselabs.com from that address. We will reply within 30 days.
How we use data
Only to run Letterhawk for you: to show opens, replies, follow-ups, and stats; to filter out false opens; to bill subscriptions; to keep the service secure; and to fix bugs.
What we collect
- Your Google email address and Google account ID when you sign in. The extension sends a Google sign-in token to our server, which checks it with Google and does not keep it. We store your email, your Google account ID, and a scrambled (hashed) copy of your Letterhawk API key. The key itself is given to the extension once and kept in Chrome's sync storage.
- Tracked message metadata: subject line, recipient addresses on To and Cc, the category you assign, a thread id when Gmail provides one, and the time the message was recorded. The message body is not uploaded.
- Open events about your recipients when the pixel in a tracked message loads: the time, the full user-agent string of the mail app or proxy that loaded it, the network operator (autonomous system number and organization) that Cloudflare derives from the connection, and the host name of the referring page. We use these to filter out Apple Mail Privacy Protection, Google's image proxy, security scanners, CRM previews, and your own views. We do not store the IP address, and we do not store a city, region, country, or any other location.
- Reply timestamps. When you open a thread you tracked, the extension checks in your browser whether a message in it came from someone other than you. If one did, only the time is sent. Letterhawk does not upload reply bodies or sender addresses, and it never reports on threads you did not track.
- Your own views of tracked threads: when you open a tracked thread in Gmail, the extension sends the thread id and the time, so your own views are not counted as opens.
- Diagnostic reports: if the extension hits an error in Gmail, it sends the error type, the time, and up to 400 characters of the error message so we can fix it. A message can occasionally include an address or a subject line. It never includes a message body.
- Outcomes you set (converted, lost, or no response) and your settings, including hot-lead thresholds and a per-recipient do-not-track list. Only you can see or change your do-not-track list.
- Billing identifiers if you subscribe: a Stripe customer id and subscription id. Card numbers stay on Stripe's hosted pages. Letterhawk does not receive them.
If you connect an AI assistant with a Letterhawk assistant key (Pro), it can read the same follow-up information you see in the dashboard and record an outcome for you. The key is shown once, is separate from the extension key, and you can revoke it in options. The assistant's provider handles what it reads under its own terms.
What we do not collect
Health information, financial account numbers, payment card data, browsing history, and location. We do not store IP addresses; Cloudflare sees the connection address only to deliver each request, as described under Sharing. The extension does not request a Gmail API scope. It works inside the Gmail page: in a compose window it reads the To and Cc addresses and the subject (uploaded as described above) and adds the pixel; in a tracked thread it reads who sent each message, which stays in your browser; in the inbox list it reads thread ids to show tracking marks; and it removes Letterhawk pixels wherever they appear in Gmail. Message bodies and page HTML are not uploaded.
Google user data
Letterhawk asks Google only for your email address and basic sign-in information (the openid and email scopes) so you can sign in. It does not request access to Gmail through Google's APIs. Letterhawk's use and transfer of information received from Google APIs will adhere to the Google API Services User Data Policy, including the Limited Use requirements. We do not use Google user data for advertising, and no person reads it except with your permission, for security, or as the law requires.
Where it is stored
Account data is stored in Cloudflare D1. Cloudflare may process requests in data centers outside your country. On your device, the extension keeps your API key, signed-in email, server choice, categories, and onboarding flag in Chrome sync storage, and tracked-thread ids and notification bookkeeping in Chrome local storage.
How long
We keep your account data until you delete your account. There is no automatic deletion. On the free plan the dashboard shows only the last 30 days, but older mail and its opens are still stored, and new opens of older mail are still recorded, until you delete the account. When you delete your account, the data is removed from the live database right away and drops out of Cloudflare's database restore history within 30 days. Stripe keeps its own billing records as the law requires.
Deletion and export
In the extension's options you can download a JSON export and delete your account. The export includes up to 5,000 tracked emails (subject, category, To and Cc addresses, sent time, thread id) and up to 20,000 opens on those emails (time, filter flags, full user-agent, network operator, and referer host). It also includes up to 20,000 of your own thread views, up to 5,000 diagnostic reports, your do-not-track list, replies, outcomes, settings, and the Stripe customer and subscription ids when you have them. It does not include your API key. If the file is marked truncated, email us for the rest. If you have a paid subscription, deleting your account first cancels it immediately. The unused part of the current billing period is not refunded. Your rows are then removed from the live database right away, and this cannot be undone. If the cancellation does not go through, for any reason, nothing is deleted. Try again, or email us and we will finish it. Those rows drop out of Cloudflare's database restore history within 30 days. Stripe keeps its own billing records as the law requires. You can also email german@hallhouselabs.com.
Sharing
We use these service providers:
- Cloudflare hosts the API, the database, and the tracking pixel. It handles each network connection, including the IP address, to deliver the request, and it keeps short-lived operational logs.
- Google verifies your sign-in.
- InboxSDK, by Streak, is the library the extension uses to work inside Gmail. It sends its own error reports and usage events to Streak (
api.inboxsdk.com). These include the extension id, the library version, and a one-way (SHA-256) hash of your Gmail address, not message contents. See Streak's privacy policy. - Stripe processes subscriptions when billing is on. Checkout sends Stripe your account email and an account id.
If you connect an AI assistant with an assistant key, the data it requests goes to that assistant's provider under its own terms. We do not sell personal information or use it for advertising. We disclose data when the law requires it, or to a buyer of Letterhawk if the business is sold, and this policy continues to apply.
Children
Letterhawk is a business tool for adults. It is not directed to children under 13, and you may not use it to track a child. If you believe we hold a child's data, email german@hallhouselabs.com and we will delete it.
Your choices and rights
You can export or delete your data in the extension's options at any time. Depending on where you live (for example the EU, the UK, or California), you may also have the right to access, correct, or delete your data, or to object to how it is used. Email german@hallhouselabs.com and we will reply within 30 days.
Changes
If we change this policy, we will post the new version here with a new effective date. If a change materially expands what we collect or share, we will tell you in the extension or by email before it takes effect.
Contact
Hall House Labs LLC
Registered Agents Inc, 4030 Wake Forest Rd Ste 349, Raleigh, NC 27609
german@hallhouselabs.com