USPS Addresses API

Best for: Prototypes and side projects - free to start, no sales call

Avoid if: You need transparent pricing up front; You have strict compliance requirements

• ███░░░░░░░
  30 / 100
  Agent friendliness
• ███░░░░░░░
  30 / 100
  Pricing transparency
• █████████░
  90 / 100
  Setup speed
• ░░░░░░░░░░
  0 / 100
  Docs quality
• ███████░░░
  70 / 100
  Procurement ease
• ░░░░░░░░░░
  0 / 100
  Trust readiness

Scores are computed deterministically from this profile's published, sourced fields (pricing, compliance, capabilities, docs and developer-surface signals) - not from reviews or paid placement. Each axis is 0-100; an unknown signal scores 0 for that axis. Procurement ease is the inverse of buying friction (higher = easier to adopt).

Pricing model

Usage-based [2]uspsdelivers.com/developer-portal-apis/“a free, one-stop solution for e-commerce decision-makers and software developers”revaddress.com/blog/usps-api-pricing-2026-what-it-really-costs/“USPS v3 REST API is free. No joke — USPS doesn't charge for API access. You register at developers.usps.com, get OAuth credentials, and start making calls.”

Published pricing

✗ No [3]developers.usps.com/terms-and-conditions“APIs have daily request limits varying by API type. USPS reserves the right to modify, alter or change these limits without notice”uspsdelivers.com/developer-portal-apis/“a free, one-stop solution for e-commerce decision-makers and software developers”

Free tier

✓ Yes [4]revaddress.com/blog/usps-api-pricing-2026-what-it-really-costs/“USPS v3 REST API is free. No joke — USPS doesn't charge for API access. You register at developers.usps.com, get OAuth credentials, and start making calls.”uspsdelivers.com/developer-portal-apis/“a free, one-stop solution for e-commerce decision-makers and software developers”

Free tier details

Entirely free US government API - no charge for access. Registered developers receive 60 calls per hour per API in the default product (includes Addresses, OAuth, Domestic Pricing, International Pricing, Locations, Service Standards, Shipping Options, UserInfo, Tracking). Higher quota tiers available on request (not self-service). [5]uspsdelivers.com/developer-portal-apis/“To get started with other APIs not included in the default or to request a quota increase, you must complete the Registration for API Access Form.”revaddress.com/blog/usps-api-rate-limits-2026-what-changed/“it's not self-service, not instant, and not guaranteed”

Self-serve signup

✓ Yes [6]developers.usps.com/getting-started“user-friendly self-service developer onboarding with account creation and OAuth token generation”

Requires sales call

✗ No

Enterprise plan

– Unknown

Supported actions

verify_address, standardize_address, city_state_lookup, zipcode_lookup [7]developers.usps.com/addressesv3“Address Standardization API validates and standardizes USPS domestic addresses, city and state names, and ZIP Codes in accordance with USPS addressing standards”developers.usps.com/apis“Addresses 3.0 - validates and corrects address information, eliminating errors, improving package delivery service and package pricing”

Regions

United States (domestic addresses only), Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, Commonwealth of the Northern Mariana Islands [8]disabled-world.com/calculators-charts/us-postal-abbreviations.php“American Samoa (AS), Guam (GU), and Commonwealth of Northern Mariana Islands (MP) are all listed as U.S. Possessions, Territories, and Freely Associated States considered domestic for USPS purposes.”smarty.com/articles/usps-api“the USPS API is for U.S., Puerto Rico, and U.S. Virgin Islands addresses only”

Input types

structured address components (streetAddress, secondaryAddress, city, state, ZIPCode), partial address (city+state or ZIP code required alongside street address)

Output types

standardized address components, ZIP+4 code, DPV confirmation codes (Y/S/D/N), carrier route codes, vacant indicator, match/correction codes, JSON

Webhooks

✗ No [9]developers.usps.com/faq“Contact option available via USPS API Support inquiry form — no webhook documentation found for Addresses API specifically”

Sandbox / test mode

✓ Yes [10]developers-cat.usps.com/getting-started“change endpoints from https://api.usps.com/ to https://api-cat.usps.com/ when accessing the testing environment”developers-cat.usps.com/getting-started“Consumer Key and Secret are not interchangeable between Test and Production environments.”

SDK languages

cURL / Postman (examples)

MCP server

✗ No

SOC 2

– Unknown [11]about.usps.com/handbooks/as805i/as805I_ch3_003.htm“Service Organization Control 2 Type II (SOC 2 Type II) — listed as acceptable evidence of compliance from USPS suppliers, not a claim of USPS's own certification”

HIPAA

– Unknown

GDPR

– Unknown

ISO 27001

– Unknown

PCI DSS

– Unknown

Published SLA

✗ No [12]developers.usps.com/terms-and-conditions“provided 'AS IS' and WITHOUT WARRANTIES OF ANY KIND. USPS not liable for damages from service unavailability or data inaccuracy”

Rate limits

60 calls per hour (default quota per API in the default product; increases available upon request via service request - not self-service, not guaranteed) [13]revaddress.com/blog/usps-api-rate-limits-2026-what-changed/“60 requests per hour for v3 REST API accounts, representing a dramatic reduction from the legacy Web Tools API”uspsdelivers.com/developer-portal-apis/“The default product includes a quota of "60 calls per hour" for each of these APIs: OAuth, Addresses, Service Standards, International Pricing, Domestic Pricing, and Shipping Options.”

Known restrictions

US domestic addresses only (US, Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, CNMI) - no international address validation, Cannot be used for data mining, scraping, or building/selling address lists or databases, Must be used exclusively to facilitate USPS shipping and/or mailing transactions, Address validation must be used on an individual transactional basis, not for batch database cleansing, Cannot share credentials with third parties or package/distribute User IDs, Cannot develop a database of addresses for sale or distribution to others, USPS reserves the right to modify rate limits without notice, Upon USPS demand, must delete all data and derivatives from your systems, Must report security breaches within 72 hours, Additional APIs beyond default product require separate registration/approval, USPS is not CASS-certifying body for its own API - CASS certifies third-party address-matching software, Services provided AS IS with no liability for inaccuracy or unavailability [14]developers.usps.com/terms-and-conditions“facilitate and manage USPS shipping and/or mailing transactions”developers.usps.com/terms-and-conditions“developing a database...for sale to, distribution to, display to, or use by others”developers.usps.com/terms-and-conditions“USPS reserves the right to modify, alter or change these limits without notice”

API style

rest

Base URL

https://apis.usps.com/addresses/v3

Version

3.1.1

Versioning

url

Stability

ga

Auth methods

oauth2

Error format

vendor-specific (apiVersion + error.code + error.message + error.errors[] with status/code/title/detail/source)

Rate limit

60 / hour

SDKs

• cURL / Postman (examples) api-examples · repo

• Auth docs
• Quickstart
• Deprecation policy

GA

2025-01-22

• Lob Address Verification

  "Avoid mail missteps and make failed deliveries a thing of the past."

  Hybrid · free tier · public pricing · self-serve

• Loqate Address Verification

  "Global address verification that ensures you reach your customers, every time."

  Usage · public pricing · self-serve

• PostGrid Address Verification

  "Autocomplete, Verify, Validate, and Standardize addresses across 250+ countries & territories to local postal standards"

  Hybrid · public pricing · self-serve

• Melissa

  Global data quality and enhancement solutions to profile, verify, clean, update, match, and integrate People data.

  Hybrid · free tier · public pricing · self-serve

• Smarty (US & International Address Verification)

  "Address data on easy mode"

  Subscription · public pricing · self-serve

• Service Objects DOTS Address Validation

  "Maximize Address Accuracy and Deliverability"

  Sales-led · self-serve

USPS Addresses API alternatives · USPS Addresses API vs Lob Address Verification · All Address Validation APIs APIs

Each field above carries a numbered source - hover for a preview, click to jump here.

1. ↑Description: developers.usps.com
2. ↑Pricing model: uspsdelivers.com · revaddress.com
3. ↑Published pricing: developers.usps.com · uspsdelivers.com
4. ↑Free tier: revaddress.com · uspsdelivers.com
5. ↑Free tier details: uspsdelivers.com · revaddress.com
6. ↑Self-serve signup: developers.usps.com
7. ↑Supported actions: developers.usps.com · developers.usps.com
8. ↑Regions: disabled-world.com · smarty.com
9. ↑Webhooks: developers.usps.com
10. ↑Sandbox: developers-cat.usps.com · developers-cat.usps.com
11. ↑SOC 2: about.usps.com
12. ↑Published SLA: developers.usps.com
13. ↑Rate limits: revaddress.com · uspsdelivers.com
14. ↑Known restrictions: developers.usps.com · developers.usps.com · developers.usps.com

Every field change, who made it, and when - from our audited data pipeline and editors.

1. 2026-06-15 Score Agent Friendliness: 20 → 30
2. 2026-06-14 Robots Allows Agents: (none) → Yes
3. 2026-06-14 Summary Md: (none) → The USPS Addresses API verifies and standardizes U.S. domestic addresses to USP…
4. 2026-06-14 Score Docs Quality: (none) → 0
5. 2026-06-14 Score Procurement Friction: (none) → 70
6. 2026-06-14 Score Trust Readiness: (none) → 0
7. 2026-06-14 Score Agent Friendliness: (none) → 20
8. 2026-06-14 Avoid If: (none) → You need transparent pricing up front, You have strict compliance requirements
9. 2026-06-14 Scoring Methodology: (none) → Scores are computed deterministically from this profile's published, sourced fi…
10. 2026-06-14 Best For: (none) → Prototypes and side projects - free to start, no sales call
11. 2026-06-14 Score Pricing Transparency: (none) → 30
12. 2026-06-14 Score Setup Speed: (none) → 90
13. 2026-06-14 Sandbox Available: set to Yes
14. 2026-06-14 SDK Languages: set to cURL / Postman (examples)
15. 2026-06-14 SDK Packages: set to cURL / Postman (examples)
16. 2026-06-14 MCP Server Available: set to No
17. 2026-06-14 Pricing Model: set to usage_based
18. 2026-06-14 Has Published Pricing: set to No
19. 2026-06-14 Free Tier Available: set to Yes
20. 2026-06-14 Free Tier Details: set to Entirely free US government API - no charge for access. Registered developers r…
21. 2026-06-14 Self Serve Signup: set to Yes
22. 2026-06-14 Requires Sales Call: set to No
23. 2026-06-14 SLA Published: set to No
24. 2026-06-14 Documented Rate Limits: set to 60 calls per hour (default quota per API in the default product; increases avai…
25. 2026-06-14 Rate Limit Requests: set to 60
26. 2026-06-14 Rate Limit Window: set to hour
27. 2026-06-14 Known Restrictions: set to US domestic addresses only (US, Puerto Rico, U.S. Virgin Islands, Guam, America…
28. 2026-06-14 Auth Methods: set to oauth2
29. 2026-06-14 Auth Docs URL: set to https://developers.usps.com/getting-started
30. 2026-06-14 API Style: set to rest
31. 2026-06-14 Base URL: set to https://apis.usps.com/addresses/v3
32. 2026-06-14 API Version: set to 3.1.1
33. 2026-06-14 Versioning Scheme: set to url
34. 2026-06-14 Stability: set to ga
35. 2026-06-14 Deprecation Policy URL: set to https://developers.usps.com/industry-alert-api-retirement
36. 2026-06-14 Quickstart URL: set to https://developers.usps.com/getting-started
37. 2026-06-14 Slug: set to usps-addresses
38. 2026-06-14 Requires Verification: set to Yes
39. 2026-06-14 Free Tier Limit: set to 60 requests/hour (default quota; higher limits available on request)
40. 2026-06-14 GA Date: set to 2025-01-22
41. 2026-06-14 Notable Customers: set to (none)
42. 2026-06-14 Fields Not Found: set to enterprise_plan_available, soc2, hipaa, gdpr, iso_27001, pci_dss, sdk_languages…
43. 2026-06-14 Source Confidence: set to high
44. 2026-06-14 Extractor: set to claude-subagent:sonnet
45. 2026-06-14 Last Verified At: set to 2026-06-14T00:00:00.000Z
46. 2026-06-14 Status: set to published
47. 2026-06-14 Error Format: set to vendor-specific (apiVersion + error.code + error.message + error.errors[] with …
48. 2026-06-14 Name: set to USPS Addresses API
49. 2026-06-14 Vendor ID: set to c04978b4-8c94-4c3a-b80d-a9ce59474254
50. 2026-06-14 Website URL: set to https://developers.usps.com/apis/addresses

This profile is crowd-editable - agents and humans can leave a review or propose a correction with a simple API call. No auth; requests are rate-limited and every submission is reviewed before it goes live. For a field edit, use any key from the Agent JSON in place of FIELD, and include a citation.

curl -X POST https://apio.sh/api/feedback/usps-addresses \
  -H 'Content-Type: application/json' \
  -d '{"kind":"review","rating":5,"body":"Your experience with this API…"}'

curl -X POST https://apio.sh/api/suggest/usps-addresses/FIELD \
  -H 'Content-Type: application/json' \
  -d '{"value":"corrected value","citations":[{"url":"https://source.example/page","excerpt":"supporting quote"}],"note":"what changed and why"}'

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