Here are well-regarded builders/developers you should consider in Kolkata, with a brief note about each and sources so you can verify recent projects and track records:

Top builders (strong presence in Kolkata)

• Ambuja Neotia — known for high‑quality, sustainability‑focused projects such as EcoSpace and Udayan; strong reputation in Kolkata for premium and mixed‑use developments. (rivirtual.in)
• Merlin Group — long track record in Kolkata with many residential and premium projects (Merlin-branded towers are prominent across the city). (rivirtual.in)
• PS Group — active in Kolkata with multiple completed projects and a reputation for design and delivery in the mid-to-premium segment. (rivirtual.in)
• Mani / Forum / Forum-Atmosphere developers (Forum Projects / Mani/associated groups) — developers behind some landmark high‑rise projects (e.g., Atmosphere/Forum projects). (en.wikipedia.org)
• Godrej Properties — national developer with several Kolkata projects focused on sustainable design and modern amenities. (rivirtual.in)
• Eden Group (Eden Realty) — established Kolkata developer with many residential schemes across price segments. (houssed.com)
• Rajwada Group / PS Group / Srijan / Shrachi (other notable local developers) — several reputable local groups with a significant Kolkata presence and multiple delivered projects. (houssed.com)

How to choose among them (quick checklist)

• Confirm RERA registration and check project-specific RERA pages for timelines and approvals. (RERA is the authoritative record for project status.) (timesofindia.indiatimes.com)
• Inspect recent completed projects in person (quality of finishes, maintenance).
• Read customer reviews on multiple portals (Makaan, Housing/RERA forums) and check for recurring issues (delays, quality complaints). (makaan.com)
• Verify title/land paperwork and builder disclosures before paying substantial amounts; consider a legal review.
• Ask for recent occupancy certificates / completion certificates for ready properties.

If you want, I can:

• Pull the latest RERA links and recent project status for 3 specific builders you’re interested in, or
• Shortlist builders by budget (affordable / mid‑range / premium) and neighbourhood (Salt Lake, New Town, EM Bypass, Ballygunge, etc.).

Which would you prefer?