Short answer — there are four kinds of platforms people use most:

• Airline / alliance award websites (the authoritative place to book): e.g., United.com (Star Alliance), Air Canada/Aeroplan, BritishAirways.com (Avios), AlaskaAir.com, American Airlines, ANA, etc. — these are where you actually complete bookings and confirm inventory. (thepointsguy.com)

• Third‑party award‑search engines (search many programs at once): popular ones include Point.me, Roame.travel, PointsYeah, Seats.aero, SeatSpy and Pointhound. These aggregate award space across multiple programs and show transfer options and estimated points needed. Many are subscription services and should be used to find options — then book on the airline program. (thepointsguy.com)

• Availability / alert tools and expert utilities: ExpertFlyer (paid) is widely used for class/fare‑bucket availability and alerts; SeatSpy and Seats.aero also offer alerts and calendar views for award space. (thepointsguy.com)

• Account/points tracking and miscellany: AwardWallet (tracks balances/expirations) and browser tools/articles (TPG, OMAAT) are often used alongside searches to manage currencies and booking steps. (awardwallet.com)

Quick pros/cons and practical tips

• Airline sites: most reliable for final booking and avoiding “phantom” availability — always verify and book here when possible. (thepointsguy.com)
• Aggregators (Point.me, Roame, PointsYeah, etc.): save huge time and show transfer paths and multiple program prices in one place, but results can occasionally differ from live airline availability and some features require paid plans. Verify on the airline site before transferring points. (wsj.com)
• ExpertFlyer / SeatSpy / Seats.aero: great for monitoring and setting alerts if your dates are flexible. (thepointsguy.com)

If you want a single quick recommendation:

• Start with a multi‑program search tool (Point.me or Roame are commonly recommended), use ExpertFlyer/SeatSpy for alerts if you’re flexible, then confirm and complete the booking on the airline or partner site. (thepointsguy.com)

If you want, I can tailor suggestions to your loyalty programs (e.g., Chase/Amex/Chase transfer partners) and travel dates, and show which tools are best for those.