What is Reverse GeoCoder?#

Reverse GeoCoder from Melissa Data is a Web Service that provides the nearest valid U.S addresses to a latitude and longitude coordinate. Reverse GeoCoder converts a geographic coordinate to a valid street address that can be used, for example, in mobile apps to locate a person in case of an emergency or to provide roadside help. It also can be used by mailers to create a targeted mailing list assembled from addresses grouped around a specific geographic location.

Why Is the service returning GE54?#

As with most most web services, a request can fail for any number of reasons internal to the service and not due to user configuration. For reverse Geo, this may simply be that the service could not perform all the searches and computations necessary to determine the nearest location to the input before the service timed out. Depending on the use case, decreasing the max distance search radius may actually be the best workaround.

What’s the maximum number of records that the user can get per request?#

The Maximum number of records returned by the service is 100. Setting a higher number (Or no number at all) in the request MaxRecords field will not change this limit.

What’s the maximum distance allowed?#

The Maximum is 10 miles regardless whether the user specifies a higher number in the MaxDistance field, or doesn’t specify anything at all.

What fields are mandatory in the request?#

The mandatory fields are CustomerID, Latitude and Longitude. MaxRecords and MaxDistance are optional. If They are not specified, the default value for MaxRecords is 100 records, and for MaxDistance it’s 10 miles.

What Lat/Long formats does the service accept?#

The service accepts only the decimal representation of the Lat and Long. Formats such as: 116°14’28.86”W or -116 14 28.86 will not be accepted. East/West, Minutes/Seconds formats will have to be converted by the user prior calling the service.

Is there a percentage to the accuracy of the results returned?#

The Distance returned (in miles) between the input and the output point will serve as an indicator of accuracy. A distance of zero means an exact match was returned.

How often is the service updated?#

Reverse Geo is updated on a scheduled quarterly basis. Additionally, the service may also be updated as needed.

What is the expected service throughput?#

Service Endpoint

Throughput (records / hour)







Service factors effecting throughput#

Distribution of the data. Being a Global Service, if inputs are randomly distributed over a wide range of Countries, searching for a name will require more of the underlying data to be accessed. Input data sets containing low country recognition may take longer – as the underlying data will search for records longer before it is determined to be an unknown name

Input Data: Input data representing rural areas, a large search radius, and or large number of response addresses will all result in more searches and algorithms performed to return the de3sired number of locations

Number of threads: the above benchmark is for a single thread of 100 record batches. Increasing the number of threads can greatly increase throughput. Users should thoroughly test the effects of the number of threads against network configuration to determine the most optimal usage.

Average Response Time

Average (ms / record)

Single Request


P95 Latency



Certifications and Compliance#

As a company, Melissa is fully GDPR compliant and holds various certifications. We are proud to take privacy and security very seriously, and aim to be transparent when detailing how we handle your data.

All Reverse Geocoder requests are secured with HTTPS and the latest TLS.

Please refer to our compliance page for more details.

What We Store and Why#

We store some minimal information from each Reverse Geocoder request for logging, diagnostic, debugging, and optimization purposes.

Melissa does NOT give or sell this information to any other entity. It is all strictly for internal use.

Also, we do NOT use received emails for any marketing or advertising purpose. Again, they are only used internally for Reverse Geocoder.

Aside from standard diagnostic and debugging information, Reverse Geocoder does use a cache of emails. This cache stores the result of the last check on that email so that users who verify an email within a short time of another user verifying the same email can get the same results faster.

For European users, emails are additionally encrypted using a one-way hash, which means that emails are impossible to decipher and are not human-readable.

See the following sections for more details.

Outside of Europe#

For users not affected by any extra privacy regulations, Reverse Geocoder securely logs emails and other internal diagnostic information. As mentioned above, all Reverse Geocoder requests are sent with current HTTPS and TLS encryption.

This cache is just emails with several numerical values attached to them. This is used for internal logging purposes, and more importantly to improve speed without sacrificing accuracy. There is nothing to tie any email to any individual, whether that be the owner of the email or the user who verified the email.

Europe and GDPR#

As of the 25th of May 2018, the European Union implemented the General Data Protection Regulations (GDPR).

These regulations apply to anyone who processes data gathered or stored in the European Union, regardless of where the data processor is located.

Overall, GDPR obligates all data collectors and processors working in Europe or with European data to transparently collect, store, and process that data, and to do so with only the minimum amount of data needed for the task at hand.

Additionally, GDPR dictates that data systems must implement data privacy and protection by default.

For more information, see this summary of GDPR from the European Union itself, or the full text of the regulations.

Emails specifically are less sensitive compared to other personal data, such as full names or addresses. GDPR does allow companies to store emails - no encryption or other obfuscation required - as long as it is hard to connect any email to any other piece of personal information, whether internally or in the event of a breach.

Other information related to emails, namely information about domains, is not considered personal data. You may find that some requests do include contact information about the domain owner, but this information is gathered from external sources, all of which are GDPR compliant in their own right.

Interestingly, since GDPR allows companies to store unencrypted emails as long as they cannot be connected to other personal information, our method of caching outside of Europe was already GDPR compliant.

But, for Reverse Geocoder specifically, we have gone beyond simple compliance.

We store information about the connection status of the MX server in the form of encrypted hashes. This means that users get the best of both worlds: the performance of our non-European email verification, and the assurance that we are more than fully GDPR compliant. As mentioned previously, all encryption is one-way.

Please do not hesitate to reach out to us with any questions regarding our GDPR compliance.

Data Across Borders#

It is important to note that GDPR does allow companies to leverage data gathered and stored outside of the GDPR sphere of influence. Therefore, we use our US-hosted cache of nearly 800 million emails to bolster email verification in Europe in only a read capacity.