As the luxury resale market continues to grow, the counterfeiters are right behind it, manufacturing new releases sometimes before the original is even launched and if you are trying to determine authenticity, working with reputable authentication companies with knowledge of the secondhand space is important.
I’ve created a list of authentication companies below and have broken down simple details for each along with wether they have a specialty (focusing on one brand) or by category.
While some authentication companies use AI, most all are done by sending images in to receive an outcome and those have multiple members that usually have a deep knowledge of a specific brand. No authentication companies are powered by one person, there is always a team behind it.
Before you choose any company, know that the goal here is to create trust within the pre-owned industry and while I trust every company on this list, mistakes can happen. No one that is on this list is out to screw anyone so if a determination comes back that you do not agree with, have a conversation with that company.

Authentic Detective
Cost: $5 on up
Good For: They have a whole team with different expertises so they can authenticate items from most categories.
Turnaround: 24 Hours
Financial Guarantee: No
Notes: Started by people that worked at Grailed and The RealReal, they have a large opinion based authentication group on Facebook and are building their own app for social selling.

Authenticate4U
Cost: $7.50 on up
Categories: Handbags, accessories, shoes and clothing
Turnaround: Information unavailable
Financial Guarantee: Information unavailable
Reviews:
TrustPilot

Authenticatefirst.com
Cost: $20 on up depending on the brand and if a certificate is needed
Categories: Handbags and accessories, shoes, clothing, jewelry
Turnaround: 2 Business days (approximately)
Financial Guarantee: Authentication fee only
Reviews:
Trustpilot

AuthethenticatorsRus.com
Cost: $15 on up depending on the brand and if a certificate is needed
Categories: Handbags and accessories, shoes, clothing, jewelry
Turnaround: Less that 24 hours as stated on their website
Financial Guarantee: No
Reviews:
None listed outside of their website

Bababebi.com
Cost: No pricing on her website but pricing used to start at $65 on up for an opinion
Categories: Hermes only, Handbags and accessories
Turnaround: Within 24 working hours after receipt of satisfactory pictures and payment of fees
Financial Guarantee: No
Reviews:
Trust Pilot

Dr. Runway
Cost: $15 on up for verbal based on brand
Categories: Handbags and accessories, clothing, shoes and jewelry from specific brands
Turnaround: 24 hours for verbal, 48 hours for certificate
Financial Guarantee: No
Location: USA
Reviews:
Trustpilot

Legit Check
Cost: $60 w/certificate or a monthly membership of $49
Categories: Handbags and accessories, sneakers
Turnaround: 48 hours
Financial Guarantee: Yes, see website for details
Location: USA
Reviews:
Trustpilot

Legit Grails
Cost: $15 on up
Categories: Handbags and accessories, clothing, shoes and jewelry from specific brands
Turnaround: 30 minutes being the quickest (fee applies)
Financial Guarantee: No, check website for refund policy
Location: USA
Reviews:
Trustpilot

Legos In My Louis
Cost: $25 for verbal, $40 with certificate
Categories: Handbags and small leather goods for a small list of brands
Turnaround: 48 hours during business hours
Financial Guarantee: No
Location: USA
Reviews:
None

Lollipuff.com
Cost: $25 starting price then goes up from there
Categories: Handbags and accessories, shoes, clothing
Turnaround: 24 hours
Financial Guarantee: Fee will be refunded if they cannot make a determination
Location: USA
Reviews:
Trustpilot

Memes Treasures
Cost: $20 on up
Categories: Handbags and accessories for specific brands
Turnaround: 60 minutes for Louis Vuitton, 24 hours for all other brands supported
Financial Guarantee: Fee will be refunded if they cannot make a determination
Location: USA
Reviews:
Facebook Reviews

Open Luxury
Cost: $30 on up
Categories: Handbags and accessories
Turnaround: 24 hours
Financial Guarantee: No
Location: USA
Reviews:
None, brand new company and James Firestein who worked at Rebag started this company and he is highly respected for his Hermes knowledge which, Openluxury is the cheapest around for authentication.

Pro Authenticators
Cost: $15 on up
Categories: Handbags and small leather goods for Louis Vuitton only
Turnaround: Minutes up to 48 hours
Financial Guarantee: Yes, if unable to determine authenticity or if they re-authenticate and the results are different
Location: USA
Reviews:
Trustpilot

Realauthentication.com
Cost: $20 on up depending on the brand and if a certificate is needed
Categories: Handbags and accessories, shoes, clothing, jewelry
Turnaround: 2 Business days (approximately)
Financial Guarantee: Authentication fee only
Location: USA
Reviews:
Trustpilot

The Fashion Detective
Cost: $20
Categories: Handbags and accessories, shoes, clothing, jewelry and watches
Turnaround: 24 business hours
Financial Guarantee: Refund the cost if a determination cannot be made
Location: USA
Reviews:
None yet

The Handbag Clinic
Cost: £34.95 on up
Categories: Handbags and accessories
Turnaround: 24 hours
Financial Guarantee: Information not available
Location: UK
Reviews:
TrustPilot

Zekos Authentication
Cost: $50 on up
Categories: Chanel handbags and small leather goods
Turnaround: 24 hours
Financial Guarantee: No but refunded if authenticity cannot be determined
Location: USA
Reviews:
Trustpilot