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Rate Limits
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GuideMarch 10, 2026
USPS API Pricing 2026 — What It Actually Costs
USPS address validation stopped being free on August 1, 2026. The published fee curve, the license that gates it, and what direct vs third-party costs.
8 min readBreaking ChangeMarch 10, 2026
USPS API Rate Limits in 2026: From 6,000/min to 60/hour
USPS v3 throughput fell from roughly 6,000 requests a minute on Web Tools to 60 per hour. What that does to checkout at peak, and five architecture patterns.
12 min readTutorialMarch 10, 2026
USPS Batch Address Validation: 50 Addresses per Call
Validate 50 US addresses in one request. The exact payloads, per-address failure handling, rate-limit backoff, and how to run a 10,000-row list through it.
10 min read