Sandcastles vs ViralSpot: which finds better reel ideas?
Sandcastles follows channels on three platforms. ViralSpot is an AI agent for Instagram, with one plan and no credits. Our team tested both hands-on, next to Aubrium.
You've seen a reel take off from an account no bigger than yours, and you want more like it. Plenty of tools promise to find them. Sandcastles and ViralSpot are two that people often weigh against each other.
Both look for outliers: reels that did far better than their account usually does. Both will break a reel down for you and write you a script. But they're built for different people.
Sandcastles is for creators who post the same video everywhere. It follows a list of channels across Instagram, TikTok and YouTube Shorts. ViralSpot is Instagram only. It's an AI agent you chat with, plus a feed of the accounts you choose to track, all on one plan with no credits to count.
Our team studied both apps hands-on in October 2026, with the same kind of searches in each and the same five reels for their script writers. We also ran everything through Aubrium, which we make, so you can see how a library built only from accounts your size compares. Both tools appear in our guide to the best viral reel finders too.
For Instagram creators, ViralSpot is the better of the two. It costs less, its scripts were the most careful and human-sounding in our blind test, and every result it returned beat its account. Sandcastles fits if you also post to TikTok and YouTube Shorts. If you want ideas from accounts your size, Aubrium beats both: on the same 90 keywords it found more than 4,000 reels to ViralSpot's 532.
Follows the channels you add across Instagram, TikTok and YouTube Shorts and flags their outliers. A global search comes with Pro and up.
An agent you chat with that finds reels, breaks them down and writes for you, plus a feed of up to 20 accounts you track. Instagram only.
What does Sandcastles do?
Sandcastles is a research tool built around channels. You keep a watchlist of accounts on Instagram, TikTok and YouTube Shorts, and it lists their recent videos with an outlier score: how far each video beat the typical views of that channel's videos from the 90 days before it.1
When you sign up, it builds a starter watchlist for your niche. You can add channels yourself, and its channel finder can filter them by size, from accounts under 10,000 followers to ones over 5 million.2 From the Pro plan up, a global search looks past your list, by the words in captions and titles.3
Open any video and Sandcastles writes it up for you: a summary, the transcript, the hook and its formula, how the story is told and how it's shot. These write-ups read well. Each costs a credit, and Pro comes with 100 credits a month.4 Its script writer then takes you from a topic to a finished script in four steps.
Plans are $49, $99 or $499 a month, less if you pay yearly.4 New accounts can start on a $5 Starter plan, offered once, without the global search.5 There's no free plan, and no refunds from Pro up.6
What does ViralSpot do?
ViralSpot is built around an AI agent. You ask for what you want in plain words, and it searches, reads reels and writes for you. It shows each step as it works, and it's honest about what it couldn't check.
Next to the agent sits a feed called Outliers. It shows the best posts from the accounts you track, ranked by how far each one beat that account's usual views. You can track up to 20 accounts, and each slot locks for 3 days once you fill it. A new post from a tracked account shows up within hours.
To look past those accounts, you ask the agent. It searches ViralSpot's own collection of posts, and that collection is built from the accounts its users track. The agent also breaks a reel down second by second, writes hooks and scripts, and can audit your own page. That audit, three changes backed by examples, was one of the best things it made in our tests.
It's one plan with no credits to count: $25 a month on a launch offer, or $20 a month billed yearly.7 There's no trial, but you can get your first payment back within 14 days.8
How are they different?
Here's the short version. Sandcastles is wide and charges as you go. ViralSpot is narrow and charges one flat price.
You follow channels on Instagram, TikTok and YouTube Shorts. Its global search reads captions and titles. A write-up of a video costs a credit, and so does a script. It can read any reel you paste in. Its scripts come from six hooks, with no caption.
A good fit if you post the same video everywhere.You chat with an agent, and it picks the search settings for you. Its feed shows only the accounts you track. Breakdowns, hooks, scripts and captions all come with the plan. Its carousels are AI pictures with the words drawn in.
A good fit if you know whose reels to watch and want one low price.How we tested them
We didn't stop at each tool's website. Our team used both apps the way a creator would, from the inside, in October 2026. Each one was measured the way its own search works.
In Sandcastles, we ran 147 keywords through its global search, sorted most viral first, and kept the first 100 results of each. In ViralSpot, that kind of search lives inside the agent, so we asked the agent to run each keyword with fixed settings: reels from the last 30 days, by accounts with 1,000 to 100,000 followers. We ran the same keywords on Aubrium's library. For the writing, both tools got the same five viral reels as six other tools, and AI reviewers, software that reads text and scores it, marked every script blind.
Sandcastles vs ViralSpot vs Aubrium at a glance
Here's how the three line up on what creators ask about most. The detail follows.
| Feature | Sandcastles | ViralSpot | Aubrium |
|---|---|---|---|
| Platforms | Yes: Instagram, TikTok, YouTube Shorts | Partly: Instagram only | Partly: Instagram only |
| How it finds reels | Partly: Channels you follow, plus a caption search from Pro up | Partly: An agent you ask, plus a feed of up to 20 accounts you track | Yes: A library you search and filter, plus rivals you track |
| Reels from accounts your size | No: No size filter on videos | Partly: Only if you ask the agent for a follower range | Yes: Every account has 1,000 to 100,000 followers |
| Every result beat its account | Partly: Not always: 7% of its scores were broken | Yes: By its own score | Yes: Every reel reached far more people than its creator has followers |
| Results about what you searched | Partly: The words in captions and titles | No: 63% of results with a caption had none of our words | Yes: Posts filed by what they're about |
| Where the creator is | No: Not shown, and no filter | No: Not shown, and no filter | Yes: On 96% of posts, with a country filter |
| Hook type on every post | Partly: After a paid write-up | No: No | Yes: Yes, with a filter |
| Your own version of a reel | Partly: A script from six hooks, no caption | Yes: Hooks, a script and a caption, in three to four minutes | Yes: A script, hooks and a caption |
| Credits to count | Partly: Credits for write-ups and scripts | Yes: None | Partly: Sparks pay for what you make |
| Inside ChatGPT and Claude | Partly: Pro and up | Yes: Yes, 38 tools | Yes: Yes |
| Blind script score, out of 35 | 19.6 | 27.5 | 29.7 |
What we found when we tested them
Here's what happened when we used the two side by side, with Aubrium beside them, one question at a time.
Whose reels does each one show you?
Both tools start you on big accounts. When we told Sandcastles we had fewer than 1,000 followers and made beauty videos, the starter watchlist it built had 29 channels, from 279,000 to 4.9 million followers, and 10 of them were brands. When we asked ViralSpot to suggest accounts for a creator with about 15,000 followers, the smallest it offered had 1.8 million.
Search is where they part. Each tool was searched its own way, so read this table one row at a time.
| Tool | How we searched | What came back |
|---|---|---|
| Sandcastles | Its global search, 147 keywords, most viral first, first 100 results. It has no follower filter for videos. | Typical account: 125,849 followers. 58% over 100,000, 9% over a million, 6% under 10,000 |
| ViralSpot | Its agent, 161 searches for reels from the last 30 days by accounts with 1,000 to 100,000 followers | 39 searches found nothing, and 33 more found three posts or fewer. The same few accounts came up again and again |
| Aubrium | Its library, the same 147 keywords as Sandcastles, most viral first, first 100 results | Typical account: 5,607 followers. None over 100,000, two in three under 10,000 |
Sandcastles shows plenty, but mostly big and often old: 24% of its top results were posted before 2024, against 4% in Aubrium. ViralSpot sizes its results to what you ask for, but it has few of them, because its collection only holds what its users track. Ask it with no size limit, and the typical account in a search had between 260,000 and 2.2 million followers.
Did their "viral" reels really beat their account?
Here ViralSpot did better than Sandcastles.
What we found when we checked the numbers
- Yes: ViralSpot: every post its search returned had beaten its account's usual views, by its own score, and none of its scores were broken
- No: Sandcastles: 7% of its outlier scores were broken, with the score equal to the view count, and sorting by score puts them first
- No: Sandcastles: in its default order, newest first, 58 of the first 100 pilates results did worse than their account usually does
- Yes: Aubrium: every reel reached far more people than its creator has followers, and the typical one reached 18 times
Sandcastles' score breaks when a channel has no recent baseline. One post from 2018, by an account with 10.8 million followers, showed up as 1,217,419 times its usual. ViralSpot's score is simple and held up. Its trouble is having enough results, not their quality.
Does the search find what you typed?
Sandcastles reads the words in a video's caption and title. It doesn't know what a video is about, or how its hook works, until someone spends a credit on a write-up. So a search is only as good as the words people typed under their posts.
ViralSpot turns your words into its own topic labels, then searches those. That can go wrong. When we searched "cat", it read the word as catering. Of the results that showed a caption, 63% had none of the words we searched. Its own agent was frank about one batch, saying most of it was content "that the topic filter mislabeled."
On the same 90 keywords, Aubrium simply had more to show.
Reels from the last 30 days, by accounts with 1,000 to 100,000 followers. Our tests, October 2026.
ViralSpot found nothing for 32 of those keywords, and Aubrium for 16. Sandcastles' global search doesn't say how many results it has, so it isn't in this count.
Neither tool shows where a creator is, and neither has a country filter. Aubrium knows the creator's country for 96% of its posts, across 200 countries, and lets you filter by it.
Whose scripts are better?
Both tools got the same five reels as six other tools that write: a face-wash ranking, a tinted sunscreen launch, a pilates class in a parking lot, a run of baking fails and a coffee cart's first quote. Six reviewers, in two rounds of three, scored every script without knowing which tool wrote it.
ViralSpot came third and Sandcastles seventh. The reviewers scored each script out of 5 for sticking to the facts. ViralSpot got a perfect 5. Sandcastles got 1.4, the lowest of all eight.
Statistics that weren't in the reels, like "up to 20% more endorphins than working out alone" and "Over 60% of tinted sunscreens come in one shade". Its scripts ran 75 to 95 seconds for reels of a minute or less. Five of its six hooks were the same stock templates on every reel, and there was no caption.
Claims you'd have to check before you say them on camera.The most human-sounding scripts of the eight. Where it didn't know a price or a number, it left a blank and said why: "I left blanks so you don't claim anything that didn't happen." But when we told it the creator's niche, it moved three of the five reels into that niche instead of keeping each reel's topic.
Top marks for not inventing facts.To be fair to Sandcastles, its write-up of a single video is good, and it reads any reel you paste in within a couple of minutes. ViralSpot's agent took three to four minutes for each answer.
Is there a better option than both?
If you post on Instagram, yes. Aubrium is a library built only from accounts your size, and it did better than both on finding reels, and on writing.
There are more than 260,000 posts in it today, from more than 190,000 creators. Every account has between 1,000 and 100,000 followers. The typical one has 12,816, and two in five posts come from accounts under 10,000. Every reel reached far more people than its creator has followers, and the typical one reached 18 times. Each post is filed into every one of the 350+ niches it fits, with its hook type, its format and the creator's country.
Against the two tools, the numbers above tell the story. In the same 147 searches, the typical account behind Aubrium's top results had 5,607 followers, to Sandcastles' 125,849. On the same 90 keywords, Aubrium had more than 4,000 reels to ViralSpot's 532.
The writing held up too. Aubrium came first in both rounds, and no reviewer scored another tool above it, and had the most "best hook of the reel" picks: 8 of 15, to ViralSpot's 2. For the sunscreen launch, the reviewers' favourite opener was Aubrium's: "Five shades on one cheek, watch which one disappears." It also kept each reel's own topic, and wrote its script, 23 hooks and caption in about 20 seconds. ViralSpot was more careful with facts, and that's worth knowing.
Around the library, My Rivals watches accounts like yours and flags the reel that's breaking out against that account's usual, and it all works inside ChatGPT and Claude. What it doesn't do: it's Instagram only for now, and there's no free plan or trial. Plans are $49, $99 or $249 a month, every plan has every tool,10 and a first plan is refunded in full within 15 days.11
What the category's viral reels have in common, counted across all of them.
Hook type, format, text on screen, talking to camera or not. Every post in the library arrives read, so you can see how it was built before you open it.
Which should you pick?
It comes down to where you post, and whether you already know whose reels to watch.
| If you… | Pick |
|---|---|
| post on Instagramand want ideas from accounts your size you haven't found yet | Aubrium |
| want to search a topicand get reels about that topic | Aubrium |
| want reels from your own country | Aubrium |
| already know the accountsyou want to watch, up to 20, and want one low price | ViralSpot |
| want careful scriptsthat leave blanks instead of guessing | ViralSpot |
| post the same videoto TikTok and YouTube Shorts | Sandcastles |
Questions people ask
Is ViralSpot better than Sandcastles?
For Instagram creators, it was in our tests. Its scripts scored 27.5 out of 35 to Sandcastles' 19.6, it never made up facts, and every result its search returned had beaten its account. If you post to TikTok and YouTube Shorts too, Sandcastles covers all three.
Which is cheaper, Sandcastles or ViralSpot?
Do they have a free trial?
Does ViralSpot work for TikTok?
Not for finding reels. Its own guide for AI agents says not to use it for "platforms other than Instagram".9 Sandcastles covers TikTok and YouTube Shorts as well. Aubrium is Instagram only for now.
Which one shows reels from small accounts?
ViralSpot, if you ask its agent for a follower range, but the results are often thin. Sandcastles has a size filter for finding channels, but none on videos, and in our searches 6% of its top results came from accounts under 10,000 followers. Every account in Aubrium has 1,000 to 100,000 followers.
Read next in Tools & Comparisons
- The best tools to find viral reels: ten tools compared, with the full numbers.
- Aubrium vs ViralSpot: two Instagram-only tools, and which one shows reels from your own country.
- Aubrium vs Sandcastles: the same 147 searches, side by side.
- The best ViralSpot alternatives: if ViralSpot's 20-account watchlist feels small.
- Sandcastles vs Virlo: two tools for posting on three platforms.
- ViralSpot vs Viral Outliers: an agent you chat with, or a search box with an API.
How we did this
Our team studied both apps hands-on in October 2026, using each one the way a creator would. In Sandcastles we ran 147 keywords through its global search, most viral first, and saved the first 100 results of each. In ViralSpot, whose search runs inside its agent, the agent ran each keyword for us with fixed settings: reels from the last 30 days, by accounts with 1,000 to 100,000 followers. For every result we saved the account, its followers, the views, the tool's own score and the caption, and we ran the same keywords on Aubrium's library. Because the two tools search in different ways, we report each one's numbers on their own and never in one chart.
The five script reels were the same for every tool that writes. Most tools were also given a short description of the creator they were writing for; Aubrium wasn't. The scripts were scored blind by AI reviewers with one scorecard and no tool names, in two rounds of three. Prices and terms are from each tool's own site and Sandcastles' help centre, read on 22 October 2026. Aubrium's numbers come from its own database, read on 23 October 2026. Apps change. If something here is out of date, tell us and we'll fix it and move the date. And yes, Aubrium makes this page.
Sources
- Video filter settingsSandcastles help centre · The outlier score, and the filters on videos. Read 22 October 2026.
- Finding channelsSandcastles help centre · The account-size filter when finding channels. Read 22 October 2026.
- Global searchSandcastles help centre · Pro and up, captions and titles. Updated 2 October 2026. Read 22 October 2026.
- Sandcastlessandcastles.ai · Plans, credits, refunds, the MCP connector. Read 22 October 2026.
- PlansSandcastles help centre · The $5-a-month Starter plan, offered once, and what it leaves out. Read 22 October 2026.
- Can I get a refund?Sandcastles help centre · Refunds by plan. Read 22 October 2026.
- ViralSpot pricingviralspot.ai · The one plan, its price, unlimited credits. Read 22 October 2026.
- ViralSpot Termsviralspot.ai · §10, the 14-day refund, once per account, first purchase only. Last updated 9 September 2026. Read 22 October 2026.
- ViralSpot llms.txtviralspot.ai · Instagram only. Read 22 October 2026.
- Aubrium pricingaubrium.com · Plans and Sparks. Read 22 October 2026.
- Aubrium refund policyaubrium.com · The 15-day refund on a first subscription. Read 22 October 2026.
- ViralSpot MCPviralspot.ai · The MCP server: 38 tools, included with the plan. Read 22 October 2026.
Changelog
- First version.
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