PAYLOADPIER FIELD NOTES · 14 OCTOBER 2026

The price stayed at $120. Your unit cost still rose 20%.

A supplier sends a revised price list. The price column looks unchanged, so your catalog update passes it through. But the case now contains ten units instead of twelve.

This synthetic example shows why supplier comparisons need an explicit pack quantity and price basis. PayloadPier turns those supplied inputs into structured differences that a buyer, developer or purchasing agent can review.

The unit-cost increase is 20%. The gross-margin change is minus ten percentage points. Those are different measures; neither is a claim about a customer's actual savings.

Try the calculation without an account

This Python 3 example uses only the standard library and runs offline.

from decimal import Decimal

old_cost = Decimal("120") / Decimal("12")
new_cost = Decimal("120") / Decimal("10")
selling_price = Decimal("20")
increase = (new_cost / old_cost - 1) * 100
old_margin = (selling_price - old_cost) / selling_price * 100
new_margin = (selling_price - new_cost) / selling_price * 100

print(f"Unit cost: {old_cost:.2f} -> {new_cost:.2f}")
print(f"Unit-cost increase: {increase:.2f}%")
print(f"Margin: {old_margin:.2f}% -> {new_margin:.2f}%")

The free fixed sample demonstrates the comparison engine in your browser. It requires no payment or API key.

Where an API helps

A spreadsheet formula can handle this one calculation. The API is useful when the same checks need to run repeatedly across supplied price-list revisions, with consistent validation and a result your software can consume.

1. Prepare comparable inputs. Export the previous and updated snapshots. Preserve text SKUs and leading zeros, and declare currency, quantity unit and whether each price is per pack or per unit.
2. Compare before updating the catalog. Send JSON rows or CSV/XLSX files to POST /api/v1/compare. The result separates added, absent, changed and unchanged SKUs and includes normalized unit costs, changed fields and source rows.
3. Route exceptions for review. A workflow might flag a unit-cost increase above 5%, a changed minimum order or a margin decline. That threshold belongs to your application; the API reports the evidence.
4. Save the result with the job. Keep a durable operation ID and the returned report in your own system. PayloadPier does not retain source files or result bodies for replay.

This can reduce repeated spreadsheet-specific comparison code and make purchasing exceptions easier to inspect. We have not measured customer time savings or revenue improvements.

Useful for developers and agents

Procurement integrations, wholesale catalog tools and ecommerce operations software can consume the same structured response. An agent can propose a review queue from the result; the API does not place orders, change your store or make purchasing decisions.

Python and Node clients, an OpenAPI contract and API-key MCP instructions are available. Scoped keys support prepaid spending caps. A successful comparison consumes one included subscription unit or $0.25 in prepaid credit. Published monthly options are $9 for 50 comparisons, $19 for 200 and $49 for 1,000; overages use prepaid credit. See billing and terms for current conditions.

The separate x402 endpoint offers 0.25 USDC per comparison on Base mainnet. Its payment flow has been tested on Base Sepolia; a real mainnet purchase remains unverified. OAuth MCP client verification is also pending. Neither is required for the REST/API-key integration.

Keep the boundaries explicit

• Exact, case-sensitive SKU matching; no fuzzy product matching, supplier scraping, OCR or currency conversion.
• Matched currencies and quantity units must agree. Duplicate SKUs and ambiguous rows need correction.
• An absent SKU means absent from that snapshot, not confirmed discontinued.
• Gross margins exclude freight, duties, taxes, payment fees, discounts and overhead.
• Up to 5,000 rows per snapshot, 2 MiB per file and 5 MiB per request. File-format validation rules also apply.
• Invalid input is not billed. After a timeout, preserve the Idempotency-Key and reconcile the outcome. A recorded replay returns 409 without another charge and does not replay the original result.

Start with the pack-size example

Run the free sample, or test your own JSON locally for free, then follow the first-comparison guide to create a PayloadPier account, fund it and issue a scoped key. Sign up with an email address and password for API access.

Which exception takes the most time in your workflow: pack-size changes, minimum orders or mismatched SKUs? Share redacted feedback through support.

Disclosure: published by PayloadPier about its own product, prepared with AI assistance. The numeric example is synthetic; no customer or revenue claim is implied.