The email that looks exactly right
You have seen the pattern. A brand you recognize reaches out about a paid integration. The writing is polished. The offer sits a little above your usual rate. There is a contract to review or a media kit to download, or a link to a creator portal where you confirm your details.
Most of those emails are real. Some are not, and the fake ones are very good now. Attackers copy a brand's exact signature, spoof the sending name, and register lookalike domains that pass a quick glance. The attachment is rarely a contract. It is usually an infostealer, packed inside a PDF, a password protected zip, or a link to a file that installs the moment you open it. It does not ask for your password. It copies the session cookies your browser already holds, which means it walks straight past two factor authentication. Within minutes the attacker has your Google session. From there they lock you out, rename the channel, and run a crypto giveaway stream to your audience, or they hold the channel for ransom.
This is not a rare event. Channel takeovers through fake sponsorship mail have hit creators of every size, and mid sized channels are a favorite target because the payout is real and the security habits are often thin. You are big enough to be worth stealing and small enough that nobody on a team is screening your inbox.
There is a second, quieter problem in the same inbox. Even when a sponsor is real, most creators have no reliable way to tell whether the offer is fair. You get a number, you have nothing to compare it against, and you either accept a lowball or spend a day asking around in Discord servers. The people sending these emails know that.
A security layer for the creator inbox
LegitSponsor is built for exactly this moment, the point where a sponsor email is sitting in your inbox and you have to decide what to trust. We are security people, not a marketing shop that bolted on a scanner. We come from the side of this that studies how account takeovers actually happen, which is why the product is built around evidence instead of gut feel.
You forward a sponsor email, or connect your inbox, and LegitSponsor returns a verdict on it. The verdict is a risk assessment, not a promise. It tells you what the message is, what signals support that read, and what you should check before you reply. It also gives you a grounded view of whether the terms fall in a normal range for a channel like yours, so you are not negotiating blind.
How the verdict is decided
This is the part we care about most, because it is where most AI email checkers get it wrong.
The verdict is decided by deterministic checks. Not by a language model, and not by a guess. LegitSponsor pulls the raw message apart and runs a fixed set of tests on the headers, the authentication results, the sending domain, the links, and any attachments. These checks produce the same result every time for the same email. A language model then reads that result and writes the plain English explanation you see, so the reasoning is easy to follow. The model never gets a vote on the outcome. It explains the decision, it does not make it.
The rule that anchors everything is DKIM. A message can only earn a Legit verdict if it carries a valid DKIM signature that cryptographically ties it to the domain it claims to come from. DKIM is a signature the sending server adds that cannot be produced without the domain's private key. If someone spoofs a brand's address but cannot produce that signature, and they cannot, the email does not pass. It is that simple and that strict. A forged from address is not evidence of anything. A verified signature is.
Everything else feeds the risk picture around that anchor. A lookalike domain, a link that redirects somewhere unexpected, an attachment type that has no business being in a first contact, a reply address that does not match the brand, all of these raise the risk and show up in the explanation with the specific reason attached. You see the evidence, not just a color.
What you actually get
You get a clear read on whether a sponsor email deserves your trust, backed by checks you can inspect line by line. You get an honest signal on pricing so you can hold your rate. And you keep the thing an account takeover is built to steal, which is the channel you spent years building.
We are launching today, August 26, 2026. If a sponsor email has ever made you hesitate before opening the attachment, that hesitation was correct. Forward it to LegitSponsor and get an answer you can defend.