If you’ve been dabbling in CPA marketing for a while, you’ve probably come across the terms SOI (Single Opt-In) and DOI (Double Opt-In). For newcomers, these might sound like technical jargon — but understanding the difference could be the key to unlocking better conversions and bigger payouts in your campaigns.
Over time, I’ve tested both models across different niches and GEOs, and while each has its own strengths and weaknesses, the choice between SOI and DOI often comes down to your goals, your traffic quality, and your willingness to optimize.
Let’s break them down — not just with definitions, but with a practical, results-oriented view.
SOI means that a lead is counted as soon as the user submits their information (usually an email or short form). No confirmation email, no extra clicks — once the form is completed, you get credited for the conversion.
DOI takes the process a step further — after filling out the form, the user must confirm their details, usually by clicking a link in a verification email. Only after this second action is completed will the conversion be counted.
From my campaigns, SOI works incredibly well for high-volume, low-cost traffic sources where speed is the priority. It’s fantastic for split-testing creatives, landing pages, and audience targeting without burning through budget too quickly.
DOI, on the other hand, shines in scenarios where lead quality matters more than sheer volume — such as finance, insurance, or niche subscription offers. In one of my DOI tests, a campaign converted at 15% initially, but after optimizing my funnel and improving follow-up email deliverability, the rate climbed to 28%.
That’s why I never dismiss DOI despite its extra step — when set up correctly, the ROI can outshine SOI in the long run.
There’s no one-size-fits-all answer to the SOI vs DOI debate. Here’s my takeaway:
In CPA marketing, testing is your best friend. Try both, track your data, and let the results guide you. Sometimes, the campaign that seems harder to convert on paper ends up delivering the highest profit.
Over time, I’ve tested both models across different niches and GEOs, and while each has its own strengths and weaknesses, the choice between SOI and DOI often comes down to your goals, your traffic quality, and your willingness to optimize.
Let’s break them down — not just with definitions, but with a practical, results-oriented view.
What is SOI (Single Opt-In)?
SOI means that a lead is counted as soon as the user submits their information (usually an email or short form). No confirmation email, no extra clicks — once the form is completed, you get credited for the conversion.
Pros of SOI:
- Extremely easy to convert – One simple action from the user and you get paid.
- Ideal for fast testing – You can validate creatives, angles, and traffic sources quickly without worrying about long conversion funnels.
- Wider range of offers – Many verticals (sweeps, dating, freebies) are SOI-friendly, making it beginner-friendly.
Cons of SOI:
- Lower payouts – Since it’s easier for users to convert, advertisers tend to pay less.
- Quality control issues – Some leads might be fake, low-intent, or generated by users who only wanted the freebie without genuine interest. This can affect your long-term relationship with networks.
What is DOI (Double Opt-In)?
DOI takes the process a step further — after filling out the form, the user must confirm their details, usually by clicking a link in a verification email. Only after this second action is completed will the conversion be counted.
Pros of DOI:
- Higher payouts – Since the advertiser gets higher quality, verified leads, they’re willing to pay more per conversion.
- Better lead quality – Users who take the time to confirm are usually more interested, resulting in better engagement and higher lifetime value.
- Potential for pay bumps – With consistently high-quality traffic, networks may increase your payout rate.
Cons of DOI:
- Lower conversion rates – Some users simply don’t bother to check or click the verification email, which means you lose out on potential leads.
- Longer funnel – Requires more patience and optimization to keep users engaged through both steps.
My Experience & Testing Results
From my campaigns, SOI works incredibly well for high-volume, low-cost traffic sources where speed is the priority. It’s fantastic for split-testing creatives, landing pages, and audience targeting without burning through budget too quickly.
DOI, on the other hand, shines in scenarios where lead quality matters more than sheer volume — such as finance, insurance, or niche subscription offers. In one of my DOI tests, a campaign converted at 15% initially, but after optimizing my funnel and improving follow-up email deliverability, the rate climbed to 28%.
That’s why I never dismiss DOI despite its extra step — when set up correctly, the ROI can outshine SOI in the long run.
Final Thoughts
There’s no one-size-fits-all answer to the SOI vs DOI debate. Here’s my takeaway:
- If you’re testing traffic sources and creatives → Start with SOI for speed and affordability.
- If you’re scaling and aiming for higher-value leads → Invest the time into DOI.
In CPA marketing, testing is your best friend. Try both, track your data, and let the results guide you. Sometimes, the campaign that seems harder to convert on paper ends up delivering the highest profit.