# Spillmark > Spillmark is the agentic Amazon growth platform. Agents test your ads, measure the sales they cause, and log what works. You approve every move. Built by an Amazon seller, tested on our own brand. Spillmark is made by Cantein, LLC. Built by Harry Burman, founder of Cantein, a hemp protein brand sold on Amazon. ## See which Meta ads make you money on Amazon - What Meta claims: Meta counts sales from people who saw or clicked your ad. Many of them would have bought anyway. - What Amazon Attribution credits: Amazon credits Meta when a tagged click leads to a buy. It misses people who saw the ad and searched later. - What you'd lose if you stopped: This is the number that decides your profit. Nobody else tells you this number. Credit is not cause. Agents measure cause. You approve the test. ## How it works 1. Upload your reports, or connect: Start with the Amazon and Shopify reports you already download. Or connect Seller Central, Meta and Shopify with read-only access. Agents work from your data. Nothing changes in your ad accounts without your approval. 2. Agents show your profit by channel: Sales minus Amazon fees, product costs and ad spend. You see what each channel really earns before you pause any ads. 3. Agents plan a holdout. You approve it.: Spillmark checks your order history. It shows whether a geo holdout can answer at your size. If it can, agents plan a test that pauses Meta in a few regions. You approve before anything pauses. You get the sales your ads caused, with a range. - Holdout test: Pausing ads in some places, and leaving them on in others, to see what changes. - Lift: The sales that happen because of your ads. Not the sales your ads get credit for. ## Why you can trust the numbers - Tests are locked: Each test design is locked before it starts, and results are never edited after. You can show your report to investors, buyers or your agency. - Your data is never shared: Your numbers are never pooled with other brands, used to benchmark them, or sold. - Read-only by default: Spillmark reads your data. Nothing changes in your ad accounts without your approval. - Every number shows its math: Tap or hover any number to see how it was worked out and where the data came from. ## Pricing The profit dashboard is free. Holdout tests, locked outcomes and alerts are paid intelligence — 7-day trial for $0, then monthly. Cancel anytime. No sales call. - Dashboard, $0 a month: The profit tool is free. Bring your reports and see where money actually comes from. - Starter, $49 a month: For brands doing $0–$50k a month on Amazon. - Growth, $199 a month: For brands doing $50k+ a month on Amazon. ## Questions people ask before they buy - Is my data safe? Spillmark asks for read-only access. We never store buyer names or addresses. Your data is never shared with other brands. Disconnect any time. We delete your data within 30 days, or delete your brand from Settings and it's gone straight away. - Am I too small? Maybe, and you'll know before you start. Spillmark checks your order history first. It shows the smallest change a test could spot. If a test can't give a clear answer at your size, it tells you. You don't pause ads for nothing. - What if a test can't give a clear answer? Spillmark tells you that before you approve a pause. You still keep the profit dashboard. You are not locked into a holdout that cannot work. - How long until I get an answer? You see profit by channel as soon as your reports are in. A holdout test runs 4 to 12 weeks. Spillmark tells you how long yours needs before it starts. - What do the AI agents do? Agents pull your data, run tests, flag problems, and prepare holdout plans. You review the results and approve every move. Nothing changes in your ad accounts on its own. - Will it change my ads? Not on its own. Agents plan the test and show you what to change. Nothing changes without your approval. - Is there a free trial? The profit dashboard is free — no card. Paid intelligence (holdout tests) starts with 7 days for $0; add a card at checkout and you are not charged until day 8. Cancel anytime from Settings before then and you pay nothing for intelligence. The free dashboard stays. - Is there a contract? No. Paid intelligence is monthly after the trial. You can cancel anytime from Settings and keep the free dashboard. - Do you offer refunds? Cancel during the trial and you are not charged. After that, cancel anytime to stop future charges. For a billing error, email hello@spillmark.com. - Can I talk to a person? Yes. Email hello@spillmark.com. - Do I need Shopify? No. Spillmark works with just Amazon and Meta. If you also sell on Shopify, you see that profit too. - What is free, and what do I pay for? The profit dashboard, imports and channel math are free. Holdout tests, the locked ledger and alerts start on Starter at $49 a month (7-day trial for $0). That is the intelligence layer — agents plan tests; you approve every move. - Why price intelligence by Amazon sales? Starter fits brands doing up to $50k a month on Amazon. Growth is for $50k+ — more tests and scored predictions as the brand gets bigger. - Can I switch plans? Yes, anytime from Settings. Changes apply from the next billing month. If your Amazon sales move past your plan's band, we'll tell you and suggest the right plan. Nothing stops working mid-test. Cancel paid intelligence anytime and keep the free dashboard. ## Links - [Home](https://spillmark.com/) - [How lift is calculated: the full method and math](https://spillmark.com/how-lift-is-calculated) - [Guides to measuring what ads cause](https://spillmark.com/learn) - [What is incrementality?](https://spillmark.com/learn/what-is-incrementality): The sales your ads cause, not the sales they get credit for, and why the two differ. - [Facebook ads for Amazon](https://spillmark.com/learn/facebook-ads-for-amazon): Where to send the traffic, what Amazon Attribution misses, and how to measure real sales. - [Amazon Attribution links](https://spillmark.com/learn/amazon-attribution-links): Create Attribution tags for Meta and other ads, add them to your links, and read what they count. - [Facebook ads for Shopify](https://spillmark.com/learn/facebook-ads-for-shopify): Connect the sales channel, pixel and Conversions API, pick ad types, and measure what the ads sell. - [Facebook ads for ecommerce](https://spillmark.com/learn/facebook-ads-for-ecommerce): Set up the pixel, catalog and campaigns for an online store, and check what the ads really sell. - [Facebook ads for supplements](https://spillmark.com/learn/facebook-ads-for-supplements): Meta's health ad rules, the evidence claims need, and why reports miss Amazon sales and reorders. - [Attribution models](https://spillmark.com/learn/attribution-models): Last click, multi-touch, data-driven and view-through: how each splits credit, and what none can see. - [Marketing attribution software](https://spillmark.com/learn/marketing-attribution-software): What attribution tools track, how they differ, what none of them can see, and when you need a test. - [What is ROAS?](https://spillmark.com/learn/what-is-roas): The formula, break-even ROAS, and how reported ROAS differs from incremental and marginal ROAS. - [What is ACoS?](https://spillmark.com/learn/what-is-acos): Amazon's ad cost of sales: how to calculate it, find your break-even, and read it next to TACoS. - [What is contribution margin?](https://spillmark.com/learn/what-is-contribution-margin): What each sale leaves after variable costs, how it sets break-even, and whether ads pay for themselves. - [What are incremental sales?](https://spillmark.com/learn/incremental-sales): The orders your ads cause, not the ones they get credit for, and how a holdout measures them. - [What is incremental revenue?](https://spillmark.com/learn/what-is-incremental-revenue): The dollar sales your ads cause, and how that differs from incremental orders and attributed revenue. - [Marketing incrementality](https://spillmark.com/learn/marketing-incrementality): Incrementality applied to marketing spend: caused sales, not platform credit. - [Incrementality measurement](https://spillmark.com/learn/incrementality-measurement): User holdouts, geo tests and models, with a Meta → Amazon path that starts from a sized geo holdout. - [Are Facebook ads worth it?](https://spillmark.com/learn/are-facebook-ads-worth-it): Break-even ROAS and a holdout test for Amazon brands on Meta—not platform credit alone. - [What is iROAS?](https://spillmark.com/learn/what-is-iroas): Incremental ROAS: caused sales divided by spend, and how it differs from reported ROAS. - [Recast alternatives](https://spillmark.com/learn/recast-alternative): Recast's Bayesian MMM next to a shortlist of alternatives, and what a Meta-to-Amazon holdout gives up. - [Amazon seller fees](https://spillmark.com/learn/amazon-seller-fees): Every fee Amazon charges sellers: selling plans, referral, FBA, storage and inbound placement. - [Amazon referral fees](https://spillmark.com/learn/amazon-referral-fees): Every category's rate and minimum, how price thresholds work, and what the fees mean for ad budgets. - [Amazon seller tools](https://spillmark.com/learn/amazon-seller-tools): Amazon's free tools and the kinds of paid tools sellers use, grouped by the job each one does. - [Holdout groups](https://spillmark.com/learn/holdout-group): The people or places that don't see your ads, and how they show what the ads did. - [Geo holdout test](https://spillmark.com/learn/geo-testing): Measure ads by turning them off in some regions and comparing sales. - [Matched market testing](https://spillmark.com/learn/matched-market-testing): How to pick test and control regions that normally sell in step. - [Difference-in-differences](https://spillmark.com/learn/difference-in-differences): The before-and-after comparison behind most geo tests, explained with sales. - [Synthetic control](https://spillmark.com/learn/synthetic-control): Build a stand-in for the test region from a blend of others. The method behind GeoLift. - [Conversion lift vs. brand lift studies](https://spillmark.com/learn/conversion-lift-vs-brand-lift): What Meta's lift studies measure, and what they can't see on Amazon. - [Marketing mix modeling vs. testing](https://spillmark.com/learn/marketing-mix-modeling-vs-incrementality-testing): When a model is enough, when you need a test, and how they work together. - [Marketing mix modeling software](https://spillmark.com/learn/marketing-mix-modeling-software): Open-source and paid MMM tools, what each needs from you, and how tests keep a model honest. - [Triple Whale alternatives](https://spillmark.com/learn/triple-whale-alternative): Triple Whale and Northbeam next to a shortlist, and what a holdout measures that a pixel can't. - [Haus alternatives](https://spillmark.com/learn/haus-alternative): Haus incrementality next to a shortlist of alternatives, with prices and what you give up. - [Measured alternatives](https://spillmark.com/learn/measured-alternative): Measured's enterprise tests and MMM next to a shortlist for Amazon brands. - [Ad measurement glossary](https://spillmark.com/learn/glossary): Plain-English definitions of the terms Amazon and Meta advertisers meet: ROAS, ACoS, TACoS, attribution, incrementality, holdout tests and more. - [Free Amazon and Meta ads calculators](https://spillmark.com/tools) - [A/B Test Calculator for Ads](https://spillmark.com/tools/ab-test-calculator): Which of two ads got more orders per click, and whether the gap is noise. - [Holdout Test Sample Size Calculator](https://spillmark.com/tools/holdout-test-calculator): How big a lift your geo holdout test can detect, and how long it needs. - [Incremental ROAS Calculator](https://spillmark.com/tools/incremental-roas-calculator): Turn holdout test results into incremental sales and iROAS. - [Meta → Amazon Halo Effect Calculator](https://spillmark.com/tools/amazon-halo-effect-calculator): Amazon sales your Meta ads cause that Amazon Attribution never credits. - [Attribution Gap Calculator](https://spillmark.com/tools/attribution-gap-calculator): Meta's reported revenue vs. Amazon Attribution vs. what your ads really caused. - [Facebook Ads ROI Calculator for Amazon](https://spillmark.com/tools/facebook-ads-amazon-roi-calculator): Reported ROAS, cost per order and profit from Amazon Attribution, with labeled what-if scenarios. - [Brand Referral Bonus Calculator](https://spillmark.com/tools/brand-referral-bonus-calculator): Your Amazon Brand Referral Bonus, effective ad cost and ROAS with the bonus. - [Product Margin Calculator](https://spillmark.com/tools/product-margin-calculator): Profit margin and markup from cost and price, or the price for a target margin. - [Amazon Profit Calculator](https://spillmark.com/tools/amazon-profit-calculator): Profit per unit and per month after Amazon fees, product cost and ads. - [ACoS Calculator](https://spillmark.com/tools/acos-calculator): Amazon ACoS, ROAS and TACoS from your ad report, checked against your break-even. - [TACoS & Blended ROAS Calculator](https://spillmark.com/tools/tacos-calculator): Amazon TACoS, blended TACoS and blended ROAS across all your ad spend. - [Break-Even ROAS & ACoS Calculator](https://spillmark.com/tools/break-even-roas-calculator): The ROAS and ACoS where your ads stop losing money, from your unit costs. - [Amazon FBA Fee Calculator](https://spillmark.com/tools/amazon-fba-fee-calculator): Referral, FBA fulfillment and surcharge fees per unit from Amazon's 2026 rate cards. - [Contribution Margin by Channel Calculator](https://spillmark.com/tools/contribution-margin-calculator): Profit per order on Amazon vs. Shopify, side by side. - [Marginal ROAS Calculator](https://spillmark.com/tools/marginal-roas-calculator): What your next ad dollar returns, from your own spend and revenue history. - [Product Sampling ROI & LTV Calculator](https://spillmark.com/tools/sample-conversion-ltv-calculator): Whether free samples pay back once sampled customers buy full-size. - [Amazon Subscribe & Save LTV Calculator](https://spillmark.com/tools/subscribe-and-save-ltv-calculator): What a Subscribe & Save customer is worth after the discount and churn. - [CAC Payback Period Calculator](https://spillmark.com/tools/cac-payback-calculator): How many orders and days until a new customer pays back what you spent. - [Max Allowable CAC Calculator](https://spillmark.com/tools/max-cac-calculator): The most you can spend to win a customer, by LTV ratio and payback window. - [Ad Budget Allocator: Meta vs. Amazon Ads](https://spillmark.com/tools/ad-budget-allocator): Split one budget between Meta and Amazon Ads by what each really returns. - [Amazon Product Launch Traffic Calculator](https://spillmark.com/tools/amazon-launch-traffic-calculator): The sessions, clicks and Meta budget a launch sales target needs. - [Amazon Reorder Point & Ad Pacing Calculator](https://spillmark.com/tools/inventory-ad-pacing-calculator): Days of stock left, how soon to reorder and how hard you can push ads. - [Ad Waste Calculator](https://spillmark.com/tools/ad-waste-calculator): How much Meta spend buys sales that would have happened anyway. - [Holdout Test Brand Size Calculator](https://spillmark.com/tools/brand-size-holdout-calculator): Whether your Amazon volume can power a clear Meta geo holdout. - [Is My Meta ROAS Real?](https://spillmark.com/tools/meta-roas-reality-check): Five questions on whether Meta ROAS is credit or cause for Amazon. - [Geo Holdout States Calculator](https://spillmark.com/tools/geo-holdout-states-calculator): Example US states to pause for a target holdout share, with MDE. - [Commercial product pages](https://spillmark.com/amazon-attribution-software) - [Amazon Attribution Software](https://spillmark.com/amazon-attribution-software): amazon attribution software - [Meta Ads Amazon Attribution](https://spillmark.com/meta-amazon-attribution): meta ads amazon attribution - [Amazon Seller Profit Dashboard](https://spillmark.com/amazon-profit-dashboard): amazon seller profit dashboard - [Incrementality Testing Software](https://spillmark.com/incrementality-testing-software): incrementality testing software - [Geo Lift Testing Software](https://spillmark.com/geo-lift-testing-software): geo lift testing software - [Amazon Attribution Alternative](https://spillmark.com/amazon-attribution-alternative): amazon attribution alternative - [Amazon Shopify Analytics](https://spillmark.com/amazon-shopify-analytics): amazon shopify analytics - [Measured Alternative](https://spillmark.com/compare/measured): measured alternative - [Triple Whale Alternative for Amazon](https://spillmark.com/compare/triple-whale): triple whale alternative for amazon - [Best Incrementality Testing Tools](https://spillmark.com/best-incrementality-testing-tools): best incrementality testing tools - [Facebook Ads Amazon Tracking](https://spillmark.com/facebook-ads-amazon-tracking): facebook ads amazon tracking - [Amazon External Traffic Tracking Software](https://spillmark.com/amazon-external-traffic-tracking-software): amazon external traffic tracking software - [Amazon Profitability Software](https://spillmark.com/amazon-profitability-software): amazon profitability software - [Amazon Advertising Analytics Software](https://spillmark.com/amazon-advertising-analytics-software): amazon advertising analytics software - [Amazon Seller Central Analytics Software](https://spillmark.com/amazon-seller-central-analytics-software): amazon seller central analytics software - [Marketing Incrementality Tools](https://spillmark.com/marketing-incrementality-tools): marketing incrementality tools - [Amazon PPC Profit Tracking Software](https://spillmark.com/amazon-ppc-profit-tracking-software): amazon ppc profit tracking software - [Facebook Ads Attribution Software](https://spillmark.com/facebook-ads-attribution-software): facebook ads attribution software - [Amazon Conversion Tracking Software](https://spillmark.com/amazon-conversion-tracking-software): amazon conversion tracking software - [Facebook to Amazon Attribution](https://spillmark.com/facebook-to-amazon-attribution): facebook to amazon attribution - [Amazon Offsite Ads Tracking](https://spillmark.com/amazon-offsite-ads-tracking): amazon offsite ads tracking - [Track Instagram Sales on Amazon](https://spillmark.com/track-instagram-sales-on-amazon): track instagram sales on amazon - [Amazon Profit Tracker](https://spillmark.com/amazon-profit-tracker): amazon profit tracker - [Amazon Seller Accounting Dashboard](https://spillmark.com/amazon-seller-accounting-dashboard): amazon seller accounting dashboard - [Amazon Profit Analytics](https://spillmark.com/amazon-profit-analytics): amazon profit analytics - [Amazon Shopify Profit Tracking](https://spillmark.com/amazon-shopify-profit-tracking): amazon shopify profit tracking - [Geo Holdout Testing Tool](https://spillmark.com/geo-holdout-testing-tool): geo holdout testing tool - [Incrementality Measurement Platform](https://spillmark.com/incrementality-measurement-platform): incrementality measurement platform - [Meta Ads Lift Testing](https://spillmark.com/meta-ads-lift-testing): meta ads lift testing - [Marketing Lift Measurement Software](https://spillmark.com/marketing-lift-measurement-software): marketing lift measurement software - [AI Amazon Analytics Tool](https://spillmark.com/ai-amazon-analytics-tool): ai amazon analytics tool - [AI Amazon Seller Assistant](https://spillmark.com/ai-amazon-seller-assistant): ai amazon seller assistant - [Amazon Advertising AI Agent](https://spillmark.com/amazon-advertising-ai-agent): amazon advertising ai agent - [AI Marketing Analytics Platform](https://spillmark.com/ai-marketing-analytics-platform): ai marketing analytics platform - [Best Amazon Analytics Software](https://spillmark.com/best-amazon-analytics-software): best amazon analytics software - [Best Amazon Profit Tracker](https://spillmark.com/best-amazon-profit-tracker): best amazon profit tracker - [Northbeam Alternatives](https://spillmark.com/compare/northbeam): northbeam alternatives - [SegmentStream Alternatives](https://spillmark.com/compare/segmentstream): segmentstream alternatives - [MCP server and API for AI agents](https://spillmark.com/agents): remote MCP at https://spillmark.com/mcp (no key needed for the calculators), REST at https://spillmark.com/api/v1 - [Security and incident reporting](https://spillmark.com/security) - [Privacy](https://spillmark.com/privacy) - Contact: hello@spillmark.com