Stringjoy is a Nashville, Tennessee-based guitar string manufacturer that started as what it described as the world's first guitar string custom shop, building made-to-order sets for players who wanted gauges and materials outside the standard factory offerings. The company manufactures its strings in-house in Nashville rather than outsourcing production, and has expanded from custom one-off sets to a full lineup of stock-gauge offerings.

The core product line covers electric, acoustic, and bass guitar strings across several named series, including the Signatures nickel-wound electrics, the Naturals phosphor bronze acoustics, the Broadways pure nickel electrics, the Foxwoods 80/20 bronze acoustics, and the Flyers coated electrics. Stringjoy also sells picks, straps, strap locks, polish, and cleaning cloths alongside its strings.

The brand has built much of its audience through educational content — long-form blog posts, YouTube videos, and gauge-selection guides aimed at helping players understand string tension, alloy choice, and tuning-specific setups. That content-driven approach, combined with a direct-to-consumer model, has given Stringjoy a notable presence among independent and tone-focused guitarists despite operating at a much smaller scale than legacy string manufacturers.

Stringjoy has 22 products cataloged on Equipboard, including Strings and Picks & Pick Holders. Their gear is featured by 11 artists, with the strongest followings in Rock, Metal, and Electronic. Notable users include Mark Morton, Ariel Posen, and Ed Garcia.