Career objective in resumes
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What CAN be useful is a 1-sentence summary. "Full-stack web developer with team lead experience, specializing in real-time applications using Rails and ReactJS."
That tells me immediately how I might fit this person into my organization and gives some hints as to what to look for in the rest of the resume. An objective CAN (and generally should) be written to convey the same sort of information, but rarely is.