CostProof — COGS ledger for Amazon FBA sellers

1. One-liner

Keeps every SKU’s landed cost accurate and audit-proof so Amazon reimburses lost FBA stock at the right number, not pennies.

2. Trend signal — why now?

On March 31, 2025 (postponed from March 10), Amazon flipped its FBA inventory reimbursement policy: warehouse-lost or damaged units are now reimbursed at manufacturing cost (COGS), not retail. If a seller doesn’t supply a per-SKU cost, Amazon “estimates” it from comparable listings — which sellers report pays pennies on the dollar. KPMG, Sovos, and Comarch all flagged this as one of the most consequential marketplace policy shifts of the year.

The mechanical consequence: a seller’s reimbursement value now depends entirely on a number — landed cost per SKU — that (a) most sellers never maintained accurately, (b) changes every time a supplier price, FX rate, or freight cost moves, and (c) Amazon will challenge with an invoice request during claim investigation. Refunzo’s own 2026 guidance: “If Amazon cannot match the invoice to the ASIN without guessing, the claim is weakened from the start.” About 40% of denied claims are appealable — but only with clean invoice→SKU→cost documentation.

Incumbent recovery tools (GETIDA, Refunzo) take 25% of recoveries and chase lost units. Sellerboard shipped a “Reimbursement Gap” report in Oct 2025 that flags shortfalls but explicitly disclaims: estimates only, “verify with Amazon,” “keep your own log of case IDs and outcomes.” Nobody owns the upstream artifact the new policy actually requires: a defensible, change-tracked landed-cost ledger that emits the evidence packet that wins the claim.

Provenance:

• Signal 1 (demand): Sellers “not happy” / “raising eyebrows” over lower COGS-basis payouts; verbatim Seller Central forum complaints (“we will give you next to nothing excluding all your branding, packaging, handling and shipping costs”) — https://sellercentral.amazon.com/seller-forums/discussions/t/68864b6f-0ab8-41ef-be18-069c33df6336 & https://shefindsways.com/amazons-new-cogs-policy-why-sellers-are-raising-eyebrows/ — 2025
• Signal 2 (feasibility): Amazon SP-API Feeds supports bulk COGS upload (25K SKUs/feed, JSON); landed-cost-per-unit is the recommended basis; invoice/PO proof requested during investigation — addressable with off-the-shelf doc-extraction + SP-API — https://marketplacevalet.com/how-to-add-cost-of-goods-for-amazon-reimbursement/ & https://developer-docs.amazon.com/sp-api/docs/mcf-best-practices — 2025–2026
• Signal 3 (economic): GETIDA/Refunzo charge 25% commission, no monthly fee; reimbursements run ~3% of annual revenue (up to $500K for large portfolios); 7+ tools compete in the category — https://www.refunzo.com/insights/top-7-amazon-fba-reimbursement-tools-2025 & https://getida.com/ — 2025–2026 Category: Platform shift

3. The opportunity

The March 2025 policy change converted a soft problem (“track your COGS for accounting”) into a hard, money-losing one (“the exact landed cost on file when a unit goes missing is what you get paid — and you must prove it on demand”). Three failures now bleed cash:

1. Stale cost — supplier raised the price, freight spiked, FX moved; the SKU’s on-file COGS is from 8 months ago, so the claim pays at the wrong basis.
2. No defensible number — seller never uploaded COGS, so Amazon’s “comparable-product estimate” pays a fraction of true cost.
3. Unwinnable appeal — the claim is denied or short-paid, but the seller can’t assemble an invoice that maps cleanly to the ASIN/SKU within the 90-day appeal window, so the 40%-appealable money is left on the table.

Incumbents are structurally misaligned: a 25%-of-recovery contingency model has zero incentive to maximize the accuracy of the per-unit basis — it profits from volume of recoveries, not correctness of each one, and it does nothing for the upstream “is your COGS current and provable” problem. CostProof attacks the basis itself: a flat-fee ledger that ingests supplier invoices, derives true landed cost per SKU, keeps it current, pushes it to Amazon via SP-API, and — when a claim is short-paid — emits a ready-to-file appeal packet with the matching invoice line highlighted. We don’t compete with GETIDA on the 25% recovery; we make every claim, whoever files it, pay the right number.

4. Target market

• Primary customer: Amazon FBA private-label and wholesale sellers doing $500K–$10M/yr GMV, 50–3,000 active SKUs, sourcing from multiple suppliers (often overseas), running lean (owner + 0–3 ops staff). US/EU/UK marketplaces first; global SP-API works everywhere.
• Why they buy (their words): “You guys lose thousands of our products every single year and now the plan is to have small businesses LOSE a bunch of money.” “Amazon’s estimate may not reflect your actual sourcing cost — especially if you get special supplier pricing or bulk discounts.” They feel directly robbed and want the number on file to be both maximal-legitimate and defensible.
• Rough TAM: ~2M+ active FBA sellers globally; the meaningful slice (>$500K GMV, multi-SKU, multi-supplier) is a few hundred thousand. At ~3% of revenue in reimbursement exposure, a $2M seller has $60K/yr at stake — a $79–$199/mo tool to protect a big chunk of that is trivially justified.
• Why now for them: The policy is live and biting this quarter. Every lost unit since March 2025 that was reimbursed on Amazon’s estimate (not their COGS) was underpaid. The pain is recurring, monthly, and quantifiable on their own settlement reports.

5. Product sketch (MVP)

• Invoice inbox: forward/upload supplier invoices, POs, freight bills (PDF, image, email); AI extracts supplier, date, item, qty, per-unit cost, freight, duties.
• Landed-cost engine: maps invoice lines to ASIN/SKU (fuzzy match + seller-confirm), computes true landed cost per unit, tracks a dated change history for every SKU (this is the audit trail Amazon asks for).
• SP-API push: one-click bulk upload of current landed COGS to Amazon’s “Manage Your COGS,” kept in sync as costs change.
• Shortfall radar: pulls reimbursement settlement data, flags every claim paid below your on-file landed cost or below true cost, with the dollar gap.
• Appeal packet generator: for a short-paid/denied claim, produces a filing-ready packet — the specific invoice line, ASIN mapping, landed-cost breakdown, and a drafted case narrative — formatted for the Seller Central case.
• Coverage dashboard: % of active SKUs with a current, document-backed COGS; “exposure if lost today” per SKU; alerts when a cost is >90 days stale.

6. AI angle — what’s load-bearing

AI does the work no spreadsheet can: reading heterogeneous supplier documents (Chinese factory invoices, freight forwarder bills, handwritten POs, multi-line packing lists in inconsistent layouts) and resolving each line to the right SKU/ASIN with a confidence score and a human-confirm loop. The hard, valuable, non-trivial step is exactly the one Amazon weaponizes: “if Amazon cannot match the invoice to the ASIN without guessing, the claim is weakened.” Remove the AI and you’re back to a seller hand-keying 800 invoice lines into a sheet and losing — i.e. the status quo that’s bleeding them. The appeal-narrative drafting is a second, lighter AI layer. AI is the product, not a chatbot bolted on a dashboard.

7. Localization angle

N/A — this is a global play. The customer is defined by the Amazon SP-API surface, not geography; the same policy and the same COGS feed apply across all marketplaces. The only “localization” is multilingual invoice OCR (Chinese, Vietnamese, German supplier docs), which is a feature inside the global product, not a separate regional cut. No payment-rail or regulatory localization adds a wedge here.

8. Business model — path to $1M–$5M ARR

• Pricing: flat tiers by SKU count — $79/mo (≤250 SKUs), $149/mo (≤1,000), $299/mo (≤5,000). No commission. Explicitly positioned against the 25%-of-recovery incumbents: “they take a quarter of what you claw back; we make every claim pay right for a flat fee.”
• ACV: ~$1,800 blended.
• To $1M ARR: ~560 sellers at $149/mo avg. The category already has hundreds of thousands of qualifying sellers and 7+ paid tools — this is a small slice.
• To $5M ARR: ~2,800 sellers, or land mid-tier aggregators/agencies that manage 20–100 seller accounts on a per-account plan (the agency channel is the multiplier).
• Expansion path: per-SKU tier creep as catalogs grow; add-on done-for-you appeal filing ($25/claim or 10% of recovered gap — undercuts the 25% incumbents and still margin-rich); multi-marketplace and Walmart WFS as the same policy logic spreads.

9. Go-to-market wedge — first 100 customers

• The complaint threads are a target list. The Amazon Seller Central forum thread on the policy, r/FulfillmentByAmazon, r/AmazonSeller, and the Refunzo/GETIDA blog comment sections have hundreds of sellers self-identifying with this exact pain by name. DM/comment with a free “what did Amazon’s estimate cost you last quarter?” exposure scan.
• Free exposure audit as the hook: connect SP-API (read-only), we show “in the last 90 days Amazon short-paid you $X vs. your true COGS.” That number sells itself; convert to paid to fix and defend it going forward. Expect strong reply on a quantified, personalized loss.
• Agency/aggregator partnerships: Amazon-account agencies and 3PLs already manage COGS reluctantly for clients. White-label/referral the ledger — one signed agency = 20–100 seller accounts.
• Wedge content with distribution intent: “Amazon paid you $8 for a $30 product — here’s the invoice that gets the rest back,” published into the FBA tool-comparison SEO graveyard (Sellerboard vs Helium10 etc.) and FBA YouTube/newsletter sponsorships where this audience already buys tools.
• Marketplace listing: Amazon Selling Partner Appstore — sellers actively browse it for reimbursement tools; we’re the only COGS-defense one.

10. Build complexity — justification

Medium. Off-the-shelf: document-extraction models, SP-API (Feeds for COGS upload, Finances/Reports for settlement data), standard web stack. Custom, non-trivial work: the invoice-line→SKU resolution engine with confidence + human-confirm, the dated landed-cost ledger with defensible change history, and the appeal-packet formatter matched to Seller Central’s case structure. SP-API onboarding (app registration, OAuth, data-protection review) adds calendar time. A 2-person team ships a credible v1 in ~3–4 months; the exposure-audit hook is buildable in ~6 weeks as a lead magnet ahead of the full ledger.

11. Gating checklist

Gate	Pass?	Note
Legal in target market	✅	Read/write of seller’s own COGS via official SP-API; no ToS conflict; sellers are entitled to set their own cost basis.
Ethical — no harm / dark patterns	✅	Helps sellers claim legitimate, documented cost. Must guardrail against inflated-cost claims (Amazon flags those) — surface that as a feature, not a risk.
Market exists (evidence above)	✅	Live policy, vocal complaints, 7+ paid incumbents, quantified $ exposure.
1–5 person team can build this	✅	2 people, ~3–4 months.
Launchable with <$50K / ₹40L	✅	Doc-AI API + SP-API + hosting; well under budget.

All five pass.

12. Feasibility score

Axis	Weight	Score	Notes
Problem intensity	20	16/20	Recurring, quantifiable, money-losing every month since Mar 2025; sellers visibly angry. Not 17+ because for many small sellers the absolute $ is annoying-but-survivable, and behavior change (uploading COGS) is required.
Demand evidence	15	13/15	Multiple independent signals: forum/Reddit complaints by name, analyst coverage, 7+ funded incumbents, public 25% pricing. Skeptic nods.
Build feasibility	15	11/15	Standard stack + doc-AI, but SP-API onboarding and the invoice→SKU resolver are real engineering; ~3–4 months not 6 weeks.
Distribution clarity	15	12/15	Named lists (forum threads, subreddits), a self-quantifying free-audit hook, Appstore, agency channel. Conversion of the audit→paid is the unproven step.
Revenue mechanics	15	11/15	Flat pricing benchmarked against a 25% incumbent norm; ACV credible; ~560 sellers to $1M is reachable. Churn risk if seller “fixes COGS once and leaves.”
Time to first revenue	10	7/10	6-week audit lead magnet → paid in 4–8 weeks post-build; not pre-sold.
Defensibility	10	5/10	Execution + accumulating per-seller cost-history lock-in (switching means rebuilding the audit trail), but incumbents with SP-API access and money can copy the ledger within ~12 months.
Total	100	75/100

13. Qualitative modifiers

Founder-fit tags

technical-heavy (SP-API integration, document-extraction pipeline, SKU-resolution accuracy) · domain-expertise-required (FBA reimbursement mechanics, claim/appeal process, what Amazon’s investigators actually accept).

Key assumptions to validate (3–5)

1. Assumption: Target sellers will connect SP-API to a new tool for a free exposure number. How to test: Ship the read-only audit; measure connect rate from 50 cold outreaches to complaining sellers.
2. Assumption: The quantified shortfall is large enough ($/quarter) to drive flat-fee conversion. How to test: Run the audit on 25 real accounts; check median 90-day shortfall vs. the $149/mo ask.
3. Assumption: Sellers value an ongoing defensible ledger, not a one-time COGS upload (retention). How to test: Interview 20 sellers post-audit on whether they’d pay monthly to keep it current + appeal-ready.
4. Assumption: Invoice→SKU resolution can hit usable accuracy on messy multi-supplier docs. How to test: Run the extractor on 200 real supplier invoices; measure auto-match precision and human-confirm time.

Risk flags

1. Platform dependency: Entire product rides Amazon SP-API and one Amazon policy. Amazon could change reimbursement rules again, build native COGS guidance, or restrict the API. Mitigate by generalizing to Walmart WFS and framing as a COGS-truth ledger, not an Amazon hack.
2. Incumbent encroachment: Sellerboard/GETIDA already touch COGS and settlements; a focused feature from them is the obvious threat. Defensibility is the accumulating per-seller audit trail and a flat-fee model they’re disincentivized to cannibalize (they earn 25%).
3. Behavior change required: Value depends on sellers actually uploading/maintaining COGS. If they won’t change behavior even when shown the loss, conversion stalls — this is the single biggest kill risk.
4. Ethics/abuse: Tool must not enable inflated-cost claims (Amazon flags and penalizes). Conservative, document-backed defaults are mandatory, not optional.

14. Structured verdict

Score:                  75/100
Verdict:                GO
Confidence:             Medium
Best-fit builder:       Technical founder with FBA/marketplace-ops domain advisor
Time to revenue:        8–12 weeks (6-week audit lead magnet, then convert)
Capital to launch:      $8–15K ($/doc-AI + SP-API onboarding + hosting)
Top 3 assumptions to validate first:
  1. SP-API connect rate on free audit — 50 cold outreaches to policy complainers
  2. Median 90-day shortfall ≥ ~10× monthly price — run audit on 25 real accounts
  3. Sellers pay monthly for an ongoing ledger, not a one-time fix — 20 post-audit interviews
Kill criteria:
  - Abandon if <15% of audited sellers show a 90-day shortfall worth ≥ $1,500
  - Abandon if <10% of completed free audits convert to paid within 30 days
  - Abandon if a top-3 incumbent ships an equivalent flat-fee COGS-defense ledger before v1

15. Next step — 1-week validation sprint

• Day 1–2: Build a throwaway read-only SP-API script that pulls reimbursement settlement data and computes “Amazon estimate vs. a seller-entered true COGS” shortfall for the trailing 90 days.
• Day 3–4: Recruit 8–12 sellers from the Seller Central policy thread and r/FulfillmentByAmazon; run the script on their accounts; record each seller’s actual 90-day shortfall and reaction.
• Day 5: Decide. Go if the median measured shortfall ≥ $1,500/quarter and ≥ 5 of ~10 sellers say they’d pay $149/mo to keep COGS current and appeal-ready. No-go if shortfalls are trivial or sellers shrug at the number.

Falsifiable outcome: a real dollar distribution of measured shortfalls and a hard count of sellers who commit to a price — not “they seemed interested.”