postman
拷贝出来放在浏览器就可以直接访问了，这个是a6纸张的渲染效果，可以根据图的大小动态的传入纸张规格
再来个大的 {"paper":"a3paper", "chemfig":"\\chemfig{CH_3-[:108,,1]N-[:54](-[:180,0.85,,,draw=none]\\mcfcringle{1.03})%\n-[:126]N-[:198]-[:270](-[:342]\\phantom{N})-[:210](=[:270]O)-[:150]N(%\n-[:210,,,2]H_3C)-[:90](=[:150]O)-[:30]N(-[:330])-[:90,,,1]CH_3}\n\n\\bigskip\n\n\\chemfig{\nO%5\n=[:270]%3\n(\n-[:210]%2\n(\n<[:150]%4\n-[:90.4,2.094]%115\n-[:18]%109\n-[:330]%110\n-[:30,,,,dlh]%111\n-[:90]%112\n-[:150,,,,dlh]%107\n-[:210]%108\n(\n-[:162]\\mcfabove{N}{H}%113\n-[:234]%114\n-[:306,,,,dbl={73}{73}]%->115\n)\n-[:270,,,,dlh]%->109\n)\n-[:270,,,2]HN%1\n-[:330,,2]%93\n(\n-[:270]%95\n-[:210]%96\n-[:270]%97\n-[:330]%98\n-[:30]%99\n-[:330]%100\n-[:270]%101\n-[:210]%102\n-[:270]%103\n)\n=[:30]O%94\n)\n-[:330]\\mcfbelow{N}{H}%6\n-[:30]%7\n(\n<:[:90]%9\n-[:30]%10\n(\n-[:330,,,1]NH_2%12\n)\n=[:90]O%11\n)\n-[:330]%8\n(\n=[:270]O%15\n)\n-[:30]\\mcfabove{N}{H}%13\n-[:330]%14\n(\n<:[:270]%16\n-[:330]%19\n(\n=[:270]O%21\n)\n-[:30,,,1]OH%20\n)\n-[:30]%17\n(\n=[:90]O%22\n)\n-[:330]\\mcfbelow{N}{H}%18\n-[:30]%23\n<:[:90]%24\n(\n=[:150]O%26\n)\n-[:30,,,1]NH%25\n-[:90,,1]%27\n-[:30]%28\n(\n=[:90]O%29\n)\n-[:330]\\mcfbelow{N}{H}%30\n-[:30]%31\n(\n-[:90]%33\n-[:30]%34\n-[:90]%35\n-[:30,,,1]NH_2%36\n)\n-[:330]%32\n(\n=[:270]O%37\n)\n-[:30]\\mcfabove{N}{H}%38\n-[:330]%39\n(\n<:[:270]%43\n-[:330]%44\n(\n-[:30,,,1]OH%46\n)\n=[:270]O%45\n)\n-[:30]%40\n(\n=[:90]O%42\n)\n-[:330]\\mcfbelow{N}{H}%41\n-[:30]%47\n(\n<:[:90]%49\n)\n-[:330]%48\n(\n=[:30]O%51\n)\n-[:270,,,2]HN%50\n-[:330,,2]%52\n(\n<[:30]%54\n-[:330]%55\n(\n-[:270,,,1]OH%57\n)\n=[:30]O%56\n)\n-[:270]%53\n(\n=[:330]O%58\n)\n-[:210,,,2]HN%59\n-[:270,,2]%60\n-[:210]%61\n(\n=[:270]O%62\n)\n-[:150]\\mcfabove{N}{H}%63\n-[:210]%64\n(\n<:[:270]%104\n-[:330,,,1]OH%105\n)\n-[:180,1.732]%91\n(\n-[:150,,,,dlhs]O%92\n)\n-[:270,,,1]NH%90\n-[:210,,1]%82\n(\n<[:270]%84\n(\n-[:330]%86\n-[:270]%87\n(\n-[:210,,,2]HO%89\n)\n=[:330]O%88\n)\n-[:210]%85\n)\n-[:150]%81\n(\n=[:90]O%83\n)\n-[:210]\\mcfbelow{N}{H}%71\n-[:150]%69\n(\n-[:90]%68\n(\n=[:30]O%70\n)\n-[:150]O%67\n-[:90]%65\n(\n<[:30]%66\n)\n-[:150]%->23\n)\n<[:210]%72\n-[:270]%73\n(\n=[:330]O%75\n)\n-[:210]%74\n-[:270,,,,drh]%80\n(\n-[:330,,,1]NH_2%106\n)\n-[:210]%79\n-[:150,,,,drh]%78\n-[:90]%77\n-[:30,,,,drh]%76\n(\n-[:330]%->74\n)\n}\n"}
PS：LaTeX是一种基于ΤΕΧ的排版系统，不光是化学方程式，其他latex语法都可以通过本镜像渲染，template.tex是模板文件，对latex排版有要求的可以自行定制
参考链接chemfig化学式转换为pdf：https://www.cnblogs.com/xiaoqi/p/chemfig.html
mol2chemfig：
Chemfig中文手册：https://chemfig.man.huzheyang.cn/index.html
用latex绘制有机化学分子式：