API Testing Sandbox — Free Postman Alternative in Browser

API Testing SandboxPostman in a tab. Fire HTTP requests against any URL straight from your browser — no install, no account, no workspace. The API endpoint validates your request and generates the equivalent cURL command, useful for codegen and CI scripts.ProgrammingTool
BIN ↔ Intel HEX / SREC ConverterConvert firmware images between raw binary, Intel HEX, and Motorola S-record. Validates checksums, preserves sparse address maps, handles linear and segmented Intel HEX addressing, and emits a raw hex preview for inspection.IoT / ArduinoTool
Cron Expression BuilderBuild a cron expression part-by-part, get a plain-English description, and preview the next five scheduled runs in your timezone. Handles ranges, lists, step values, and named days.ProgrammingTool