The most honest comparison here is an arithmetic one
Both sell contact data for cold outreach. The difference is not the feature list. It is what a usable phone number is allowed to cost, and how many of them you need.
The short answer
You are just starting, have no budget for an annual contract and want to begin today.
→ Apollo
Published price list, free entry tier, self-service without a sales call. You can pull your first list within an hour.
You call across Europe and your connect rate is the bottleneck.
→ Cognism
Phone-verified mobile numbers plus do-not-call screening. The premium pays off as soon as an hour of calling is expensive enough.
You want data plus sequences, dialler and inbox in one place.
→ Apollo
Apollo is database and outreach tool in one product. Cognism is deliberately only the data source, connected to your CRM.
Your targets are German mid-market firms with little online presence.
→ Neither, look at Dealfront
Both build their databases around people. A 180-employee company whose management is not active on LinkedIn is thinly represented there.
Direct Feature Comparison
Strengths and weaknesses based on real user experiences and data architectures.
Apollo.io
US provider, since 2015. A large contact database plus an outreach tool in one, with a published price list and a free entry tier. The cheapest serious tool in this category.
The greatest strengths
The weaknesses
Cognism
UK provider, since 2015. Sells not a toolbox but contact data at the highest quality it can manage, focused on mobile numbers for direct dialling.
The greatest strengths
The weaknesses
In-depth market analysis: Who is suitable for what?
The difference is an arithmetic problem, not a matter of taste
Apollo and Cognism sell the same good: the ability to reach a specific person. They differ in what a reachable person is allowed to cost.
Run the numbers with your own figures. Assume a salesperson costs you a certain amount per fully loaded hour, and manages a fixed number of dial attempts in that hour. If one vendor delivers a 20 percent connect rate and the other 35 percent, the difference is not a database detail. It is a third of the working time of your most expensive employee.
With two salespeople dialling half-time, that calculation almost always tips toward the more expensive vendor. For a founder making twenty calls a week on the side, it almost always tips toward the cheaper one. There is no universal answer here, only your numbers.
Where Apollo clearly wins
At getting started. There is a free tier, there is a published price list, and there is no sales process in front of it. You can pull a list this afternoon and start your first sequence tomorrow. That absence of friction is real value, especially when you do not yet know whether your ideal customer profile is right.
Apollo is also a tool rather than a source. Sequences, dialler and inbox are included. If you have neither a CRM nor an outreach tool yet, that saves two further contracts. Cognism assumes that environment already exists at your end.
Where Cognism clearly wins
At the number. Phone-verified means somebody actually called and confirmed. That is expensive and slow, which is why not everyone can afford it. In Europe the gap is wider than in the US, because European mobile numbers are harder to infer from public sources.
Then the legal part. Cold calls to business contacts are narrowly framed in Germany, and do-not-call screening takes an argument away from your own legal team. Anyone who has bought software inside a larger company knows how much that single point can be worth.
The point where neither one helps
Both answer: how do I reach this person. Neither answers: why should this person listen to me now.
That is not a criticism of the products, it is how they are built. A contact database is sorted by people, not by events. The trigger sits elsewhere: on the company's news page, in a fresh job posting, in an official notice, in a new certification, in an investment reported by the local paper.
If your first calls fail because nobody picks up, Cognism is the answer. If they fail because somebody picks up and then does not understand why you are calling, neither is.
Neither Apollo.io nor Cognism fit?
Kodo Leads does not sell a database sorted by people. It sells a short list of companies with the evidenced reason why now. To build it we read the company's own news page, its job postings, the commercial register and official notices.