Originally, DJs were hybrid curator-performers who would select and play sets of the day’s hottest records on turntables—the eponymous “discs”—and use complex analog techniques to tweak the music as it played. DJs still do all of this today—although the analog techniques have largely been replaced with digital software. While some DJs focus almost exclusively on setlist-building and nightclub performance and others are more production-oriented, most do a combination of both. 

The traditional live DJ setup includes a mixer, two turntables, a sound system, and headphones, but a plethora of digital tools are now available to supplement this. Performing DJs may mix music on the fly, or use looping, effects, and other techniques to change the sound or structure of a track. Often, they create a seamless and thrilling flow by manipulating intros and outros, matching tempos, keys, and audio levels, and generally smoothing out transitions. DJs today fill many roles, including performer, manager, accountant, promoter, and social media coordinator.

There are several opportunities for specialization as a DJ:

• Club and Festival DJ: A producer/DJ focused on playing long two- to three-hour sets featuring genre-specific selections. These DJs often create original music and remixes and integrate live remixing and production elements as well as augment their shows with custom/creative video content and lighting, in addition to running sound for performers. They push the limits to create engaging performances for fans drawn to their particular style of music or originality in mixing. Livestreaming DJing has more recently increased in popularity, offering audiences a live experience from their homes.
• Mobile DJ: These DJs perform at events such as weddings, parties, and other celebrations, and are focused on playing long gigs that last the whole night or the duration of the event featuring crossover (mainstream and pop) selections. Fans appreciate their ability to curate a mix of popular music from different genres. Like the club and festival DJ, mobile DJs can run sound for performers. 
• Turntablist: Focused on playing short routines (six minutes) for competitions, turntablists use the latest gear and performance techniques such as beat mixing/matching, scratching, and beat juggling, often in concert-style settings. They can manipulate their equipment to function as a musical instrument and create new music from existing sounds for live remixing. They may even be members of a band. Their audience is impressed with their technical ability and creativity.  
• Radio/Podcast DJ: These DJs work in a prerecorded mix format, with podcasts being a natural extension for this specialization. They create a mix for listeners, blending the audience’s favorite styles while introducing them to new music. DJ podcasts provide an opportunity to reach a wider audience and engage with fans, as well as promote music and events.