# DataFast vs Seline

Canonical: https://inetgeek.com/compare/datafast-vs-seline/

Every value below is read from DataFast's and Seline's own documentation. See https://inetgeek.com/methodology/ for how.

## At a glance

| Criterion | DataFast | Seline |
| --- | --- | --- |
| Free tier | No | No |
| Kind of free offer | Free trial | Free trial |
| What the free plan includes | Nothing standing — the only free access is a 14-day trial with no card. The entry Starter tier, once paid for, lists 10,000 monthly events, one website, one team member and three years of data retention. | A 7-day free trial of the Pro plan with every feature; the pages state there is no free plan. |
| Credit card to start | No | No |
| When the free offer ends | You can try DataFast for free for 14 days and you don't even need a credit card! | 7 days from the start of the trial. |
| Entry paid plan | Not readable. The pricing block renders its plan contents in full and then prints "$ /month" with an empty figure and "Save $NaN" — in a headless browser, after twenty seconds, on every extraction tier this site has. | From $9 a month, billed monthly, at 10,000 events a month on a single Pro plan that carries every feature. |
| Pricing model | Traffic-based plans metered in monthly events rather than pageviews, from 10,000 to over 10 million, monthly or yearly with two months free on yearly. | One Pro plan with every feature, priced by monthly events: pageviews and custom events share one limit, from 10,000 events at $9 to 20,000,000 at $649 a month, billed monthly or yearly (yearly gives two months free). Above 20,000,000 events the page says to contact them. |
| Sites or apps included | One website and one team member on Starter, the entry tier. Growth raises both to 30. | The plan lists unlimited websites, and the FAQ says pricing is per website, with other sites linkable to one that has an active Pro subscription so they share its event limit. |
| Revenue attribution from a payment provider | Supported | Supported |
| Payment providers connected | Stripe, LemonSqueezy, Polar, Shopify, WooCommerce, Paddle, Dodo Payments, and others. | Stripe and Polar connect directly with a read-only key; any other payment provider, Paddle and Lemon Squeezy named, sends revenue as custom events. |
| AI and search crawler tracking | Supported | Not supported — Counts visits referred from AI assistants as a channel; bot traffic is filtered out |
| Retention window | Three years of data retention on Starter, the entry tier; five or more on Growth. | Unlimited on the Pro plan, which is the only plan; the feature list says forever data retention. |

## Where they differ

### What the free plan includes

- DataFast: Nothing standing — the only free access is a 14-day trial with no card. The entry Starter tier, once paid for, lists 10,000 monthly events, one website, one team member and three years of data retention. ([source](https://datafa.st/))
- Seline: A 7-day free trial of the Pro plan with every feature; the pages state there is no free plan. ([source](https://seline.com/pricing))
- Lean: none. No documented basis to lean either way on this criterion.

### When the free offer ends

- DataFast: You can try DataFast for free for 14 days and you don't even need a credit card! ([source](https://datafa.st/))
- Seline: 7 days from the start of the trial. ([source](https://seline.com/pricing))
- Lean: none. No documented basis to lean either way on this criterion.

### Entry paid plan

- DataFast: Not readable. The pricing block renders its plan contents in full and then prints "$ /month" with an empty figure and "Save $NaN" — in a headless browser, after twenty seconds, on every extraction tier this site has. ([source](https://datafa.st/))
- Seline: From $9 a month, billed monthly, at 10,000 events a month on a single Pro plan that carries every feature. ([source](https://seline.com/pricing))
- Lean: none. No documented basis to lean either way on this criterion.

### Pricing model

- DataFast: Traffic-based plans metered in monthly events rather than pageviews, from 10,000 to over 10 million, monthly or yearly with two months free on yearly. ([source](https://datafa.st/))
- Seline: One Pro plan with every feature, priced by monthly events: pageviews and custom events share one limit, from 10,000 events at $9 to 20,000,000 at $649 a month, billed monthly or yearly (yearly gives two months free). Above 20,000,000 events the page says to contact them. ([source](https://seline.com/pricing))
- Lean: none. No documented basis to lean either way on this criterion.

### Sites or apps included

- DataFast: One website and one team member on Starter, the entry tier. Growth raises both to 30. ([source](https://datafa.st/))
- Seline: The plan lists unlimited websites, and the FAQ says pricing is per website, with other sites linkable to one that has an active Pro subscription so they share its event limit. ([source](https://seline.com/pricing))
- Lean: none. No documented basis to lean either way on this criterion.

### Payment providers connected

- DataFast: Stripe, LemonSqueezy, Polar, Shopify, WooCommerce, Paddle, Dodo Payments, and others. ([source](https://datafa.st/llms.txt))
- Seline: Stripe and Polar connect directly with a read-only key; any other payment provider, Paddle and Lemon Squeezy named, sends revenue as custom events. ([source](https://seline.com/revenue-analytics))
- Lean: none. No documented basis to lean either way on this criterion.

### AI and search crawler tracking

- DataFast: Supported ([source](https://datafa.st/docs/bot-traffic-tracking))
- Seline: Not supported — Counts visits referred from AI assistants as a channel; bot traffic is filtered out ([source](https://seline.com/))
- Lean: 82% DataFast / 18% Seline — documented support level. inetGeek's own reading, computed from the two values above by the rules at https://inetgeek.com/methodology/, not a provider claim.

### Retention window

- DataFast: Three years of data retention on Starter, the entry tier; five or more on Growth. ([source](https://datafa.st/))
- Seline: Unlimited on the Pro plan, which is the only plan; the feature list says forever data retention. ([source](https://seline.com/pricing))
- Lean: none. No documented basis to lean either way on this criterion.

## Which should you choose?

Pick DataFast if Tying revenue back to the channel that produced it. DataFast connects a payment provider per website and reports revenue per visitor rather than pageviews alone, which is a different question from the one the rest of this category answers.

Pick Seline if A founder who wants Stripe or Polar payments credited to the visit behind them, alongside visitor journeys, funnels and profiles, on one plan priced by monthly events, from $9 a month for 10,000 events, with data hosted in Germany.

Consider something else: DataFast — You need to know the price before signing up. The pricing block lists what each plan contains and never renders the figure — it prints an empty amount and a literal NaN — so the only way to learn the cost is to start the trial.

Consider something else: Seline — You need a free plan or a self-hosted option: Seline offers only a 7-day trial with no card, is hosted only, and states no SOC 2 or similar audit. Its direct revenue connections are Stripe and Polar; any other processor has to send revenue as custom events from your own code.

## Documented by only one

One side documents these and the other does not. An absence is a missing source, not a stated "no" — except where a line says the other page was READ on a date and does not mention it, which is a sourced observation and the only one-sided case this site leans on.

- Works without cookies: Seline: Supported — A cookie-based tracking mode exists as an optional setting and is off by default
- Self-hostable: Seline: Not supported
- GDPR / data residency: Seline: Seline is legally based in Poland, and its application servers and databases run on Hetzner in Germany; sub-processors listed are Hetzner, Stripe and Postmark.
  - DataFast: not stated on https://datafa.st/, read 2026-09-21. Corrections: https://inetgeek.com/contact/
  - Lean: 22% DataFast / 78% Seline — documented, against a vendor page that does not state it (checked 2026-09-21).
- Encryption at rest: Seline: The DPA says visitor data is encrypted in transit (HTTPS) and names encryption among its protection measures; it does not say stored data is encrypted at rest.

## Questions this comparison answers

**Entry paid plan: DataFast or Seline?**

DataFast: Not readable. The pricing block renders its plan contents in full and then prints "$ /month" with an empty figure and "Save $NaN" — in a headless browser, after twenty seconds, on every extraction tier this site has.
Seline: From $9 a month, billed monthly, at 10,000 events a month on a single Pro plan that carries every feature.

**Should I choose DataFast or Seline?**

Pick DataFast if Tying revenue back to the channel that produced it. DataFast connects a payment provider per website and reports revenue per visitor rather than pageviews alone, which is a different question from the one the rest of this category answers.
Pick Seline if A founder who wants Stripe or Polar payments credited to the visit behind them, alongside visitor journeys, funnels and profiles, on one plan priced by monthly events, from $9 a month for 10,000 events, with data hosted in Germany.