E-commerce
Verify the address at checkout, then follow up with the customer before shipping if it looks doubtful.
PRICINGPrices excl. VAT, no commitment
Stop losing money to invalid addresses.
A returned package costs you twice: the shipping, then the reshipment, if the customer does not cancel. The API checks the address before the label is printed.
14 days, 100 validations, no credit card.
The four plans
-
Free trial
14 daysSee the effect on your packages, no credit card.
$0for 14 days
- Validations
- 100 in total
- Price per validation
- Freeincluded in the trial
- The same checks as the paid plans
- API key at signup
- No credit card required
- Ends automatically after 14 days, no commitment
-
Starter
StoreFor a store that ships a few dozen packages a day.
$33per month, excl. VAT
- Validations
- 2,000 per month
- Price per validation
- $0.0165$33 ÷ 2,000 validations
- API key and a dashboard showing your usage
- Quota resets on the 1st of the month (UTC)
- CSV import guide and Shopify / WooCommerce examples
- Email support
-
Pro
For volumeFor volumes where every return shows up in your margin.
$90per month, excl. VAT
- Validations
- 10,000 per month
- Price per validation
- $0.0090$90 ÷ 10,000 validations
- Everything in Starter
- Five times the Starter volume
- 45% less per validation than Starter
-
Enterprise
CustomFor a marketplace or a logistics network.
Custom quote
- Validations
- Unlimited, no monthly cap
- Price per validation
- Custom quotebased on your volume
- Everything in Pro
- No monthly quota to watch
- Price set by email based on your volume
Approximate prices. Billed in euros: €29 and €79 per month, excl. VAT (exchange rate of September 2026).
Starter and Pro begin with the free trial. Moving to the paid plan is then done on simple request, and nothing is charged automatically.
No subscription: 0.02 USDC per callPay per call
Developers and AI agents: pay per call, no account.
0.02 USDCper validation
No account, no key, no subscription. Each call is paid with x402, in the X-PAYMENT header, on the Base network. The exact price is in the 402 response: an agent never has to guess it.
POST /validateX-PAYMENT: <x402 proof>// 0.02 USDC per validation, Base network{"address": {"street": …, "zip": …}}The response is the same as with a subscription. A call covered by a subscription reports price_paid: 0.0.
The problem
A returned package costs you twice.
The outbound shipping, then the reshipment, if the customer does not cancel. Verifying the address before printing the label means acting before that second trip.
Industry ballpark
22%
of delivery failures are said to be caused by an incorrect address.
Industry ballpark
$17–30
per failed package: return, reshipment, a call to the customer.
Calculated price
$0.0090 to $0.0165
per validation, on Pro and then on Starter. That is the number to set against it.
Our service does not measure these two ballparks and their source is not cited here. Compare them with your own numbers: your carrier knows your real failure rate.
How it works
One request, three steps.
Our API standardizes the street, city and ZIP code, locates the address and says whether it is deliverable. A doubtful address is fixed before it ships.
-
01
Send the address
Call
POST /validatewith the street, city, state, ZIP code and country, from your back office, an order webhook or a spreadsheet."street": "100 stewart st" -
02
Receive the validation
The standardized address, its GPS coordinates, its deliverability and a confidence score from 0 to 1.
"deliverability": "residential" -
03
Ship the corrected address
Doubtful addresses are corrected or set aside before they go to the carrier. That is where the return is avoided.
"line1": "100 Stewart Street"
Use cases
Where the check plugs in.
Logistics
Verify a shipping file before handing it to the carrier. The guide provides a CSV import script to adapt.
Marketplaces
Ask your sellers for a verified address at signup, rather than chasing returns after the fact.
Frequently asked questions
Before you subscribe.
Another question? Write to address-validator@kder-ai.com
Do I need a credit card for the free trial?
No. The trial lasts 14 days and includes 100 validations, with no credit card and no commitment. At the end, you pick a plan, or nothing happens.
What happens if I go over my quota?
The quota is monthly and resets on the 1st of the month (UTC). Once it is reached, the API answers 402 with quota_atteint: nothing extra is billed and no automatic charge takes place. Your usage is visible in your dashboard. To move up to the next plan, write to us.
What happens to the addresses I send you?
They are used for validation. The cache keeps a SHA-256 fingerprint, never the address in clear text. Nothing is resold or used for advertising.
Do you cover Réunion and international addresses?
United States addresses are optimised (USPS DPV); France and overseas territories are verified by the Base Adresse Nationale; addresses from other countries are accepted, but verification there stays partial: a response is not a full confirmation. The known limits are published in the API manifest.
How long does integration take?
A first call takes a few minutes: POST /validate with your key in the X-API-Key header. To connect it to your orders, the guide covers the direct call, CSV import, Shopify and WooCommerce, with code examples. There is no Shopify app to install: the call is made from your own service.
GDPR compliance. The addresses you send are used only for validation and are neither resold nor used for advertising. The cache keeps a SHA-256 fingerprint, never the address in clear text. Operating logs pseudonymize the IP address (SHA-256 and salt) and are purged after 30 days. You can request deletion of your account data at any time.
Start with 100 free validations.
14-day free trial, no credit card. Or run a first test right now, no account needed.