Free in this category almost always means one of two things: a permanent free tier with a hard feature ceiling, or a time-limited trial of the paid product with a countdown attached. Both are useful, but they solve different problems. A permanent free tier is worth using for a single, narrow job done repeatedly. A free trial is worth using for a short, intensive evaluation before a purchase decision. This entry sorts five real options into those two categories and scores each one on what it delivers before a credit card is required.
At a glance
| # | Tool | Free access | Engines covered free | Paid from |
|---|---|---|---|---|
| 1 | Otterly.AI | 14-day trial, no card | 5, plus Gemini as a paid add-on | $29/mo |
| 2 | HubSpot AEO Grader | Free forever | 3 | Not applicable |
| 3 | Otto SEO (Search Atlas) | 7-day trial, no card | Up to 5, limited | $79 to 99/mo |
| 4 | Knowatoa | Free instant audit plus 7-day trial, no card | 3 | $59/mo |
| 5 | AirOps | Solo tier, free forever | 1 | About $2,000/mo Pro |
1. Otterly.AI
Free access: 14-day trial, no credit card required, at the full Lite-tier feature level.
Free-access score: 66/100 (coverage 21/25, execution 4/25, ease 18/20, value 14/20, transparency 9/10).
Otterly.AI’s monitoring dashboard, the same view a trial account sees during the 14-day free period.
Otterly.AI’s trial does not hold much back. A reader who signs up gets the full Lite-tier experience for two weeks: prompt-level citation tracking across ChatGPT, Perplexity, Google AI Overviews, Google AI Mode, and Microsoft Copilot for free, plus the GEO audit engine that scores a single URL against more than 20 citation-readiness factors, including schema markup. Gemini tracking exists too, but only as a paid add-on layered on top of the trial, so the free coverage tops out at five engines, not six. That audit alone is worth running even for a team that has no plan to buy the tool, since it returns a concrete, dated checklist rather than a vague score.
The trial ends at 14 days, and continuing costs $29 a month for the Lite plan, which caps at 15 prompts, enough for one brand in one market. Gemini stays a paid add-on at that tier too, so a brand that needs Gemini coverage pays extra from day one, trial or not. A brand tracking more than one market or product line will outgrow Lite fast, and the next plan, Standard, costs $189 a month, a steep jump with no bridge tier.
2. HubSpot AEO Grader
Free access: Free forever, no trial period and no plan to upgrade out of.
Free-access score: 65/100 (coverage 12/25, execution 5/25, ease 19/20, value 20/20, transparency 9/10).
The HubSpot AEO Grader report, generated instantly from a domain with no ongoing subscription.
HubSpot AEO Grader is a diagnostic, not a monitoring platform, and it is genuinely free with no paid tier attached. Entering a domain returns a one-time report covering AI brand visibility, sentiment analysis, competitive insights, share of voice scoring, and a market position reading, checked against ChatGPT, Perplexity, and Gemini. Because HubSpot built it as a lead-generation grader rather than a product, there is no account to log back into for a trend line: each run is a fresh snapshot, not a tracked history.
The tradeoff is coverage and depth. Google AI Overviews and Copilot are absent, so a brand whose customers lean on Google’s answer panel gets no read on that engine at all. The grader also stops at the finding; nothing in the report becomes a published fix without a separate tool. It is the fastest way to get a first, no-cost read on how three major engines currently describe a brand, and nothing more than that.
3. Otto SEO (Search Atlas)
Free access: 7-day trial, no credit card required, on the Starter plan.
Free-access score: 62/100 (coverage 8/25, execution 18/25, ease 17/20, value 13/20, transparency 6/10).
Otto SEO’s project dashboard during a trial, with the OTTO agent queue visible alongside LLM Visibility.
Otto SEO is the only tool on this list whose free trial includes an agent that deploys changes rather than only reporting them. The OTTO SEO agent runs technical fixes, on-page optimization, and content updates through a connected pixel, with each change requiring approval before it goes live. That execution layer is real during the 7-day trial, which is a genuine differentiator against pure trackers.
The catch is engine coverage. LLM Visibility, the module that tracks brand mentions across ChatGPT, Gemini, and Perplexity, is described by the vendor as limited on the Starter tier specifically, with full tracking gated behind the $159 to $199 a month Growth plan. A reader evaluating Otto SEO for its execution ability during the trial gets a fair test; a reader evaluating it for AI-engine tracking does not get the full picture until they pay for Growth.
4. Knowatoa
Free access: A free instant audit with no signup, plus a separate 7-day trial with no credit card, both on the Starter feature set.
Free-access score: 61/100 (coverage 12/25, execution 10/25, ease 18/20, value 13/20, transparency 8/10).
Knowatoa’s BISCUIT diagnostic view, available during the 7-day Starter trial.
Knowatoa offers two free entry points stacked on top of each other: a free AI visibility audit that needs no signup at all, and a 7-day trial with no credit card for readers who want more than a single snapshot. Both run on the Starter engine set: ChatGPT, Google AI Mode, and Google AI Overviews. The standout feature, even at this level, is the BISCUIT framework, a diagnostic that explains why a competitor is showing up in an AI answer instead of the tracked brand, which goes further than a plain citation count.
Starter caps at 30 tracked questions and excludes Gemini, Claude, Meta AI, and Perplexity entirely; those four engines require the $199 a month Growth plan. A brand that needs a fuller engine picture will find the free tier informative but incomplete, useful for a first diagnostic pass rather than a full visibility program.
5. AirOps
Free access: Solo tier, free forever, not a trial.
Free-access score: 50/100 (coverage 8/25, execution 10/25, ease 10/20, value 16/20, transparency 6/10).
AirOps’s Solo tier interface, tracking ChatGPT citations and sorting gaps through the Opportunities Engine.
AirOps is the only platform here with a permanent free tier built for a real, if narrow, ongoing job: solo marketers who want AI visibility tracking without a subscription. The Solo tier tracks 100 prompts against ChatGPT only, with a 20,000-task monthly allowance, and feeds whatever gaps it finds into the Opportunities Engine, which sorts them into four action types (create, refresh, outreach, community). That classification step is a genuine planning tool, not just a report.
Two limits keep it from ranking higher. Coverage stops at ChatGPT; Google AI Overviews, Gemini, Perplexity, and Google AI Mode all require the Pro plan, priced around $2,000 a month according to third-party reporting rather than a published rate. And AirOps carries a real setup curve even at the free tier, since the Opportunities Engine and its workflow logic take time to configure before they return a usable answer. A solo operator willing to invest that setup time gets a durable free tool; a team wanting quick, broad coverage will hit the ChatGPT-only ceiling fast.
What free access does not replace
None of these five tools solve the problem a paid AI SEO platform is built for: tracking a brand across every major AI engine on a fixed schedule, month after month, with a way to act on what changes. HubSpot’s grader and AirOps’s Solo tier are permanent but narrow. Otterly.AI, Otto SEO, and Knowatoa are broad but temporary. A team that needs ongoing coverage across all five core engines, plus the ability to turn a gap into a published fix without switching tools, eventually needs a paid plan somewhere.
How these free-access scores were calculated
Each free-access score above uses this directory’s published 100-point weighting: coverage 25 points, execution 25, ease of use 20, value 20, and transparency 10, documented in full on the methodology page. The difference here is scope: these scores grade what a reader gets before paying, not the full paid platform. Otterly.AI’s paid Index entry, for example, scores differently from its free-access score above, because the paid entry evaluates the complete product rather than a 14-day window into it. Readers who want the full-platform picture for any tool with a directory entry can check its tool profile directly.
What to read next
- The full ranking these free tools sit alongside: The 10 Best AI SEO Tools in 2026
- Otterly.AI’s full paid-platform entry: /tools/otterly-ai/
- AirOps’s full paid-platform entry: /tools/airops/
- Temso’s entry and current Index score: /tools/temso/
- The scoring formula behind every score on this site: /methodology/