Grammarly vs Undetectable AI affiliate programs
Grammarly and Undetectable AI are AI writing tools that both run affiliate programs. Grammarly lists $0.20 per free signup + $20 per upgrade through Impact; Undetectable AI lists 25%-30% of ongoing lifetime revenue. Grammarly lists the longer referral cookie: 90 days against 60. aifilliate records each program from a cited vendor source and does not rank the two.
| Recorded term | Grammarly Verified | Undetectable AI Verified |
|---|---|---|
| Commission | $0.20 per free signup + $20 per upgrade | 25%-30% of ongoing lifetime revenue |
| Structure | One-time | Recurring |
| Cookie window | 90 days | 60 days |
| Network | Impact | Not stated |
| Payout threshold | Not stated | $50 USD |
| Terms checked | 2026-08-22 | 2026-08-22 |
| Source | Open source ↗ | Open source ↗ |
What matches, what differs
Differences
- Payout structure differs: one-time against recurring.
- Grammarly lists the longer referral cookie: 90 days against 60.
In common
- Both are AI writing tools.
What these terms mean in practice
Attribution splits between day 60 and day 90. A referral who clicks today and subscribes on day 75 is still credited by Grammarly, but no longer by Undetectable AI.
A customer who stays subscribed for two years pays out on every qualifying renewal with Undetectable AI, and once with Grammarly. Which produces more depends on plan price and retention, neither of which appears in published terms.
Which record fits which promoter
- Grammarly: suits traffic that deliberates before buying — the 90-day window still credits slow conversions.
- Undetectable AI: suits audiences that convert quickly; its 60-day window is shorter, so timing matters more.
What is not published
Anything below has to be confirmed with the vendor before either offer can be modelled. aifilliate records it as unknown rather than estimating it.
- Grammarly does not publish a payout threshold.
- Undetectable AI does not publish the platform running the program.
How to read these two records
These payouts do not share a basis — one is quoted as a percentage, the other as a flat amount per conversion. A percentage of an unknown plan price and a fixed bounty are not the same unit, so aifilliate does not rank them.
Grammarly pays one-time commission and Undetectable AI pays recurring, which typically matters more than the headline rate over a customer's lifetime. Grammarly lists the longer referral cookie: 90 days against 60.
aifilliate publishes no ranking between Grammarly and Undetectable AI. Which program earns more depends on plan price, conversion rate, retention, and refund reversals in your own audience — none of which appear in published affiliate terms. Confirm eligibility, paid-search and trademark rules, and payout timing with each vendor before promoting either.