Programmers must know online gadgets

1. Run code online
2. javascript tools
3. css tools
4. php tools
5. html tools
6. Regular testing tool
7. sql tools
8. json tool
9. xml tool
10. asciidoceditor
11. favicon online production
12. color conversion
13. One-click cutout
14. ruby tools
15. python tools
16. crontab time calculation
17. Image base64 encoding
18. markdown editor
19. placeholder image
20. Base conversion