FREE • PRIVATE BY DEFAULT • NO ACCOUNT

Find broken CSV rows before your import.

Paste a CSV or choose a file. The validator runs inside this browser—no upload, no account, no wallet. Find structural errors before connecting a spreadsheet, CRM, AI agent or database.

≤ 256 KiB local • RFC4180-style quoting • UTF-8

Run a real local check

Paste an authorized CSV (takes priority over selected file)

Or select a UTF-8 CSV file (processed locally)

Required column headers (optional, comma separated)

Your local quality report

Only finding codes, row/column numbers and counts appear here. Raw data is never included in the exported report.

Formula-like warnings may include legitimate negative numbers. Confirm against your import target.

x402 • Base • USDC 0.005

Need an agent-ready paid check?

The same owner's separate VM5 service offers a paid RFC4180-style CSV report for 0.005 native Circle USDC on Base (eip155:8453) per independently authorized POST. It processes up to 32 KiB of non-sensitive buyer-supplied CSV. No subscription.

Do not send customer PII, secrets, wallet keys, invoices, confidential CSV, medical or financial records to any external API. Use only free local checking for private content.

I own this CSV or have permission to process it externally. I understand that copying the payload exposes the original CSV to my clipboard; using the optional wallet checkout sends my CSV to the separate VM5 server. Do not use sensitive data. I authorize the optional, single 0.005 native Circle USDC payment on Base (chain 8453) to the displayed original VM5 merchant wallet. Signing an EIP-712 authorization can move real funds. I understand it is not refundable just because I change my mind.

View buyer payment & API instructions ↗ See free fictional server example ↗ Alternative VM5-owned full buyer checkout ↗

POST /v1/csv-preflight. HTTP 402 is a quote, NOT a sale. The FREE checker never uploads. Only after two consent boxes and a direct Pay click, the page gets a real x402 quote using FICTIONAL data, asks YOUR wallet for a limited 0.005 USDC EIP-3009 signature, and sends the actual CSV exactly once to VM5 only AFTER that signature. No private keys, automatic charge, subscription, hidden approval or retry. If settlement is unclear, do NOT sign again before checking your wallet. The separate VM5 operator receives any verified payment, not this static site.

What is different?

FREE • Browser-local

Structural parse, line numbers, duplicate headers/rows, empty cells, formula-like values, JSON findings export. Purely heuristic; not a guarantee of valid import.

PAID • Independent x402 API

HTTP POST returns deeper row/column counts, duplicate/empty/type mismatch checks and formula warnings in machine-readable JSON. Buyer-initiated paid server processing—not free, not a security audit.

Built with disclosed AI assistance by one independent owner. VM2 provides the free site; VM5 is the separate same-owner paid API operator. Historic outside purchases were for a different fixed synthetic GET; there are zero verified independently paid orders for the buyer-input POST. No fake testimonials or payment claims.

Inspect this CSV checker source ↗ · CSV API guide ↗