10 Free Browser-Based Tools Every Backend Developer Should Bookmark

As a backend developer, I spend a surprising amount of time on small but repetitive tasks — converting a subnet mask, decoding a JWT, formatting a SQL query, or generating test data before a demo. These aren't hard problems, but they slow you down when you have to hunt for the right tool every time. Here are 10 free, browser-based tools I keep coming back to. No login, no install — just open and use. 1. IP / Subnet Calculator Handy Dev Tools — IP Calculator Paste a CIDR like 192.168.1.0/24 and instantly get the network address, broadcast address, wildcard mask, usable host range, and binary/hex notation. Pair it with the Subnet Split tool to divide a network into equal subnets by count, host requirement, or prefix length — results exportable as CSV. Useful when designing VPC address spaces or writing firewall rules and you need to double-check your math fast. 2. CloudFront Signed URL Generator Handy Dev Tools — CloudFront Signer Generates AWS CloudFront signed URLs entirely in the brow