The short answer
Choose someone who has shipped a catalogue site for an Indian distributor and can point you at it. I am Kundan Khatri, founder of ZeroTheory AI Pvt Ltd; the reference build is Santosh Electricals in Chennai — 2,000+ products, 14 authorised brands, 1,479 indexed pages, and ₹4,00,000 in organic revenue within 10 days of launch, before any ad spend. The site is live and you can inspect all of it before we speak.
Four questions that separate real capability from a portfolio
Ask to see a live B2B catalogue they built, not a design mockup. Ask how many indexed pages it publishes — anyone who has done this knows the number. Ask what the client's result was, in denominated terms. Ask who will actually write the code, and whether you will ever speak to them.
A vendor who cannot answer the second question has built brochures, not catalogues, and the difference is the entire reason to do this.
What I do not do
Brand identity, advertising campaigns, media buying, or app development. Four clients a quarter, so if you need it sooner than that queue allows, an agency will serve you better and I will say so on the first call.