Google Address Validation vs. Melissa Global Address (US)

When choosing an address validation service, businesses often balance two priorities: how accurately it confirms deliverable addresses and how broadly it covers global data.

Both Melissa Global Address API and Google Address Validation API offer strong capabilities in this space. However, they differ in purpose, data foundation, and output interpretation.

Below are the functional differences between the two solutions, followed by findings from our U.S. address study comparing how each performs in real-world scenarios.

Feature and Capability Comparison

Study: Testing Real-World Address Deliverability

We conducted a study evaluating how each Address Validation API performs on U.S. addresses.

Over 1,000 addresses - including both valid and invalid examples - were tested across a range of formats and regions.

Our focus is on postal accuracy and deliverability, particularly when handling incomplete or inconsistent address inputs.
 

Sample Selection

We tested 1,096 U.S. addresses - both valid and invalid - against both Google and Melissa’s address validation services. The samples were randomly distributed across all regions within the United States and included:

• Different levels of correction needs
  e.g., typos, missing pre-/post-directions, alias street names, and incomplete data.

• Missing/Incorrect components
  e.g., thoroughfare name, locality, administrative area, or postal code information.

• Special cases
  e.g., CMRA (Commercial Mail Receiving Agency), PBSA (street-formatted private mailbox or student accommodation address), P.O. Box, military (APO/FPO/DPO) addresses, rural-style or pre-LACS addresses, vacant addresses, unique ZIP Code addresses, phantom routes, USPS alternate address formats, and alias addresses.

→ We intend for this diverse sample to reflect real-world address scenarios.

Disclaimer

Findings are based on tests conducted in September 2025 using the current production APIs. Because both systems and postal data update regularly, results should be viewed as time-specific observations, not permanent benchmarks. Additionally, results are dependent on the input data provided. Users may see different results when utilizing their own data.

Service Specific Categorization

For this comparison, we grouped Melissa and Google’s statuses into High, Medium, and Low confidence levels.

Google – Three validation criteria based on DPV Confirmation Levels - Returned in the DPVConfirmation field:

• Full Validation - Y

• Partial Validation - D or S

• Invalid - N or Unreturned

These come from the USPS CASS portion of Google Address Validation API, based on official CASS data, and are equivalent to Melissa’s USPS CASS-certified validation results.

Melissa – Three validation criteria based on Melissa’s Validation Statuses - Returned in the Results field:

• Full Validation - AS01

• Partial Validation - AS02

• Invalid - All other results

All U.S. address validation results from Melissa are USPS CASS-certified.

Quantitative Results

Key Findings for Google Address Validation API

Valid Address Rejected When Extra Details Are Provided

When extraneous details are provided in a field (e.g., subpremise in the example below), Google’s CASS engine sometimes fails to validate the address, while Melissa correctly isolates and validates the full address for accurate delivery.

In our test, about 15% of the valid addresses that Google’s CASS validation fails to validate are due to extraneous details.

USPS:  212 E Martin St Apt 3, Edgerton, KS 66021 - Valid Address

Valid Address Rejected When Extra Fields Are Provided

When extraneous fields are included in the address, Google sometimes fails to validate the address and marks it as undeliverable. Melissa correctly interprets and validates the full address while flagging the extra data. 

In our test, about 25% of the valid addresses that Google’s CASS validation fails to validate are due to extraneous fields.

USPS: Valid Address - 3321 Old Highway 7 S, Holly Springs, MS 38635

Google Address Validation API:
Conflicting Results Between Google Maps Data and USPS CASS Validation

Google’s Address Validation API uses two data sources - Google Maps Places and USPS CASS - producing separate validation results for U.S. addresses when CASS is enabled.

As a result, the USPS CASS validation may conflict with Google’s Places Data.

In our tests, Google’s Address Validation API returned conflicting results between its Places and CASS data for about 26% of all addresses.

Google Places fails to validate many valid addresses by USPS CASS.

USPS Valid Address - 204 E Locust Ave, Lapwai, ID 83540

Summary

We compared the USPS CASS engine in Google’s Address Validation API and Melissa’s Global Address API using over 1,000 U.S. addresses representing varied data quality and formats. The study evaluated how each handles validation for addresses with missing, incorrect, or incomplete data.

Melissa showed stronger performance in authoritative postal validation and deliverability, accurately standardizing unformatted address inputs.

Google offers strength in location recognition and mapping. However, it produces inconsistent results between its Maps Places data and USPS CASS validation, leading to confusion and potential false negatives.