SOI vs DOI Offers: Single vs Double Opt-In Explained

SOI vs DOI: what is the difference?

In affiliate marketing, an SOI (single opt-in) offer pays when a user fills in a short form, such as an email address or a zip code, and submits it. A DOI (double opt-in) offer pays only after the user also confirms that sign-up, most often by clicking the link in a confirmation email. DOI offers usually pay more per conversion but convert less often; SOI offers convert more often but bring more low-quality leads, so advertisers check them harder.

Both are lead offers, which is why they are usually priced as CPL (cost per lead), a type of CPA. The difference is simply where the conversion is counted: at the form, or at the confirmation.

What is an SOI offer?

An SOI offer counts a conversion the moment the user submits valid details. Nothing else has to happen. Common SOI formats you will see on affiliate networks and offerwalls:

• Email submit: the user enters an email address on the advertiser’s landing page, often to get a newsletter, a coupon, or a free guide.
• Zip submit: the user enters a zip or postal code as the first step of a longer flow, such as an insurance quote or a local deals site. The zip is the conversion; anything after it is a bonus for the advertiser.
• Short form: name, email and a few profile questions, typical for survey panels and comparison sites.
• Sweepstakes entry: the user enters a prize draw by giving an email address. The entry is the lead; the prize is a separate, unlikely event.

Because the bar is low, SOI offers are easy for users to finish and quick to track. They are also the easiest offers to fake, since a bot or a careless user can type any address that looks real.

What is a DOI offer?

A DOI offer adds a second step that proves the person behind the sign-up is real and wants it. In most cases that step is the confirmation email: the advertiser sends a link to the address the user entered, and the conversion is only counted once the link is clicked. Until then, the lead is pending and the publisher earns nothing for it.

Some networks use “DOI” more loosely, for any offer with a second confirming action: verifying a phone number with a code, completing a second form page, or finishing a profile. Always read the offer’s requirement text, because the payout depends on what the advertiser counts, not on the label.

Email marketers use the same terms for their own lists; the guide to getting newsletter subscribers who read covers that side.

SOI vs DOI side by side

The rows on rates and payouts describe the usual direction, not fixed numbers. Payouts depend on the advertiser, the country and the vertical, and change often.

Which pays more, SOI or DOI?

Per conversion, DOI almost always pays more. There are two reasons. First, the advertiser gets a better product: a confirmed address that reaches a person who asked to hear from them, which they can legally mail in more countries and which is less likely to bounce. Second, fewer users finish, so the advertiser can pay more per confirmed lead and still spend the same per visitor.

Per click, the answer is less clear. What you earn from an offer is its payout times how often users finish it, which is the logic behind EPC (earnings per click). A high DOI payout that few of your users confirm can earn less than a modest SOI payout they finish easily, and the reverse is just as possible.

Judge offers by what they earn after reversals, not by the headline payout, and give DOI offers time: a lead that confirms three days later still counts.

Lead quality, scrubbing and fraud

Any offer that pays for a form submission attracts people who fake form submissions. Advertisers and networks defend themselves in a few common ways:

• Scrubbing: the advertiser checks leads after the fact and rejects invalid ones, such as duplicates, disposable addresses, addresses that bounce, or details that do not match the target country. Rejected leads are reversed, so a publisher who was credited loses that payout again.
• Moving the conversion point: an advertiser who gets too much junk on SOI switches the offer to DOI. Confirmation is a cheap filter for most bots and typos.
• Pattern checks: bursts of sign-ups from one network, identical form timing, or many leads from one device all point to automation or one person farming the offer.

DOI is not proof against fraud. A fraudster with access to many inboxes can confirm each one, and tools that click every link in an email can trigger a confirmation no person made. That is why advertisers keep measuring what happens after the confirmation, such as opens, logins or purchases. Ad fraud and bot traffic explains the wider patterns, and What is a reversal rate? covers how rejected leads show up in your earnings.

The consent rules behind SOI and DOI

Opt-in is a legal concept before it is an affiliate one. A lead is personal data, and in many countries an advertiser may only send marketing emails with the person’s consent. The rules decide which countries an advertiser can run SOI in and where they need DOI. The summary below is general information, not legal advice; checked on October 22, 2026.

European Union: provable consent under the GDPR

The GDPR defines consent in Article 4(11) as a freely given, specific, informed and unambiguous indication of the person’s wishes, by a statement or a clear affirmative action. Article 7 adds that when processing is based on consent, the controller must be able to demonstrate that the person consented, and that withdrawing consent must be as easy as giving it. A bare SOI form says little about who typed an address in. A confirmation from the inbox is much stronger evidence, which is one reason European advertisers prefer DOI.

Germany: double opt-in is the expected standard

German unfair competition law, section 7 of the UWG, treats advertising by email without the recipient’s prior express consent as an unreasonable nuisance, with a narrow exception for existing customers and similar products. In a 2011 ruling (BGH, I ZR 164/09), the Federal Court of Justice held that an advertiser must fully document each consumer’s consent, and that a consumer who confirmed their address through double opt-in and later denies consenting must show why. In practice, that is why DOI is the default for email lead offers aimed at Germany. The same ruling also found that a confirmation email does not prove consent to phone advertising, so phone leads need their own consent.

United Kingdom: specific consent for marketing email

The UK Information Commissioner’s Office says in its guidance on electronic mail marketing that you must not send marketing email to individuals unless they have specifically consented to email from you, for example by ticking an opt-in box. Its “soft opt-in” exception covers existing customers only, not new contacts or bought-in lists. The guidance does not require double opt-in, but the consent has to be specific to the sender.

United States: CAN-SPAM is opt-out based

The FTC’s CAN-SPAM Act compliance guide describes an opt-out model rather than an opt-in one: commercial emails need accurate header information, a subject line that is not deceptive, a clear disclosure that the message is an ad, a valid physical postal address, and a working way to opt out, which must be honored within 10 business days. The guide says each separate email in violation can bring penalties of up to $53,088, and that both the company whose product is promoted and the company that sends the email can be held responsible. Because the law does not demand opt-in, SOI offers are common in the US, but state privacy laws and the rules for calls and texts can be stricter.

Mailbox providers ask for confirmation too

Google’s email sender guidelines tell senders to confirm each recipient’s email address before subscribing them, to avoid opt-in boxes checked by default, and not to buy email addresses. Mailing unconfirmed SOI leads puts an advertiser’s inbox placement at risk.

How publishers should present SOI and DOI offers

If you run an offerwall or an earn page, your users meet these offers as “Sign up for X” or “Enter to win Y”. How you frame them decides whether users finish them, whether the leads hold up, and whether users trust your wall. A few rules work on every platform:

1. Say what the user is signing up for. “Join the X newsletter and confirm your email” is honest. “Get free coins” with no mention of the sign-up is not.
2. Make the confirmation step visible for DOI. Tell users the reward arrives only after they click the link in the email, and to check their spam or promotions folder. This is the single most common reason DOI offers go unfinished, as covered in why users don’t finish offers.
3. Present sweepstakes as entries. A user entering a prize draw has not won anything. The FTC’s guide on the word “free” (16 CFR 251.1) says the conditions of a free offer should be set out clearly at the outset, close to the offer itself, so that no one is likely to misunderstand them. Apply the same spirit to your own wording.
4. Remind users they will get emails. Users who sign up only for the reward and then mark the advertiser’s emails as spam hurt the advertiser, and the offer may be paused for everyone.
5. Never coach users to fake details. Real details are the product being bought. If a user is not willing to give an address they read, the offer is not for them.
6. Disclose that you earn from offers. Your users should know you are paid when they complete one. Affiliate disclosure rules explains what to say and where.

Rewarded users behave differently from users who found an offer on their own, which advertisers account for when they price lead offers. Incentivized traffic explained covers that trade-off, and choosing the offers your users see explains how to keep offers that do not fit your audience off your wall.

If you are the advertiser: choosing SOI or DOI

Start from what a lead is worth to you and where you can legally mail it. If you target Germany or other markets where provable consent matters, DOI is the safer choice. If your goal is reach in a market with opt-out email rules, and your follow-up flow qualifies leads anyway, SOI can work, as long as you scrub leads and measure what they do next.

Many advertisers combine the two by paying for steps: a smaller payout for the submission and a larger one for the confirmation or a later action, so publishers are rewarded for both. Multi-event offers explains how that works, and the lead generation guide covers how to work out your maximum cost per lead. If you are new to how offers reach publishers in the first place, start with What is an affiliate network?

Frequently asked questions