It's possible to publish adverts in OLX, through OLX Group Real Estate Marketplaces.
To make sure your OLX export works well, take care of the following extra validations that are required.

OLX.PT

Field	Description	OLX Validation
title	*String / Required* Title of the advert.	string 111 chars max 5 chars min - if limits are exceeded, the title is not truncated - links or email addresses are not allowed - following characters cannot be provided more than three times in a row: `! ? . , - = + # % & @ * _ > < : ( ) \|`
description	*String / Required* Description of the advert.	string 9000 chars max 20 chars min - capitalized descriptions are not accepted - links or email addresses are not allowed - following characters cannot be provided more than three times in a row: `! ? . , - = + # % & @ * _ > < : ( ) \|`
contact.name	*String / Required* Name of the contact person for advert customization	string min 2 characters max 100 characters
contact.phone	*String / Required* Phone number of contact person for advert customization.	int 9 digits min 10 digits max country validation
price	*Number / Required* Price value of the advert.	int or float 0 (zero) is not allowed max size 13 characters
images.url	*String / Optional* URL of an advert image.	Array, at least one must be sent. Smallest side must have at least 300px max size 5MB
attributes.urn > urn:concept:net-area-m2 and urn:concept:gross-area-m2 and urn:concept:terrain-area-m2 and urn:concept:usable-area-m2	*Number / Required for some category_urn* URN for an area attribute.	int min 1 max 15.000.000
attributes.urn > urn:concept:number-of-rooms	*String / Required for some category_urn* URN for the number-of-rooms attribute.	string Refer to the Taxonomy API for more information.

OLX.RO

Field	Description	OLX Validation
title	*String / Required* Title of the advert.	string 70 chars max 5 chars min - if limits are exceeded, the title is not truncated - links or email addresses are not allowed - following characters cannot be provided more than three times in a row: `! ? . , - = + # % & @ * _ > < : ( ) \|`
description	*String / Required* Description of the advert.	string 9000 chars max 20 chars min - capitalized descriptions are not accepted - links or email addresses are not allowed - following characters cannot be provided more than three times in a row: `! ? . , - = + # % & @ * _ > < : ( ) \|`
contact.name	*String / Required* Name of the contact person for advert customization	string min 2 characters max 50 characters
contact.phone	*String / Required* Phone number of contact person for advert customization.	int 9 digits min 14 digits max country validation
price	*Number / Required* Price value of the advert.	int or float 0 (zero) is not allowed max size 13 characters
images.url	*String / Optional* URL of an advert image.	Array, at least one must be sent. Smallest side must have at least 300px max size 5MB
attributes.urn > urn:concept:net-area-m2 and urn:concept:gross-area-m2 and urn:concept:terrain-area-m2 and urn:concept:usable-area-m2	*Number / Required for some category_urn* URN for an area attribute.	int min 1 max 10.000.000
attributes.urn > urn:concept:number-of-rooms	*String / Required for some category_urn* URN for the number-of-rooms attribute.	string Refer to the Taxonomy API for more information.

OLX.PL

Field	Description	OLX Validation
title	*String / Required* Title of the advert.	string 70 chars max 5 chars min - if limits are exceeded, the title is not truncated - links or email addresses are not allowed - following characters cannot be provided more than three times in a row: `! ? . , - = + # % & @ * _ > < : ( ) \|`
description	*String / Required* Description of the advert.	string 9000 chars max 20 chars min - capitalized descriptions are not accepted - links or email addresses are not allowed - following characters cannot be provided more than three times in a row: `! ? . , - = + # % & @ * _ > < : ( ) \|`
contact.name	*String / Required* Name of the contact person for advert customization	string min 2 characters max 50 characters
contact.phone	*String / Required* Phone number of contact person for advert customization.	int 7 digits min 14 digits max country validation
price	*Number / Required* Price value of the advert.	int or float 0 (zero) is not allowed max size 13 characters
images.url	*String / Optional* URL of an advert image.	Array, at least one must be sent. Smallest side must have at least 300px max size 5MB
attributes.urn > urn:concept:net-area-m2 and urn:concept:gross-area-m2 and urn:concept:terrain-area-m2 and urn:concept:usable-area-m2	*Number / Required for some category_urn* URN for an area attribute.	int min 1 max 10.000.000
attributes.urn > urn:concept:number-of-rooms	*String / Required for some category_urn* URN for the number-of-rooms attribute.	string Refer to the Taxonomy API for more information.

You can implement on your side a notification any time the adverts doesn't meet the rules to be published on OLX, or you can create a Help page for our clients, with the previous rules.
In both cases will help clients improving their adverts and making sure their adverts will be automatically exported to OLX.