The messages started early last Sunday.

"Happy 10th birthday to my favourite record shop, Monorail Music," said Mogwai's Stuart Braithwaite on Twitter, and his sentiment was echoed by Edwyn Collins, Frightened Rabbit, Optimo, BMX Bandits, RM Hubbert and many more.

Monorail's memo was typically modest: "It's our 10th birthday today. Amazing really. Thanks for supporting us and allowing us to be here," it said. They'll officially mark a decade in business with a cult-pop knees-up this Sunday.

Ten years ago, musician Stephen "Pastel" McRobbie joined forces with Dep Downie, then of Missing Records, and former Herald music writer John Williamson to open Monorail Music in Glasgow, a congenial, passionate record emporium with a keen eye for vinyl and a penchant for independent sounds. "Glasgow is an amazing music city and we hoped that we could put a record shop in the middle of it all," says Pastel, frontman of indie luminaries The Pastels. "We set out to be friendly, curious, forward-looking, specific and community-minded, and we were lucky to have immediate allies in Teenage Fanclub [who financially invested in Monorail], Chemikal Underground, Optimo [also marking 15 years this week] and others."

Monorail soon gained a reputation for excellent stock – local and global, upcoming and vintage, alternative classics and outlandish rarities – and in-store gigs, including a Belle And Sebastian album launch that witnessed karaoke turns from Franz Ferdinand's Alex Kapranos.

"I can't say it wasn't hard work, especially for Dep, but at no time did I think we'd fail," says Pastel. "And the shop has slowly grown – and grown better – through the years."

This positive tone is at odds with widespread accounts of record retail despair. Pastel et al are not in denial, nor immune to the decline of physical music consumption, but remain optimistic and full of ideas (such as their spin-off, Monorail Film Club).

That outlook is reflected by the shop's brightness, warmth and accessibility. "We didn't want it to be an intimidating environment: we wanted young kids, people's parents or grandparents to be able to come in and ask for a record," says Pastel.

Downie, too, emphasises the user-friendliness of their Kings Court location. "I always wanted us to be a city-centre record shop because, when I was a kid, coming in from Lanarkshire, I wouldn't have known about record shops in the west end. I'd have known about shops in the centre. That's why it's important we're here, even though we'd perhaps make more money on Byres Road."

This sense of ideology over commerce courses through Monorail and much of Glasgow's counter-culture: the shop's collaborative nature and sense of artistic community is amplified by Craig Tannock, who owns venues/cafe-bars Stereo and Mono (Monorail is housed within Mono), and previously helmed the renowned 13th Note on Glassford Street – a hang-out steeped in 1990s DIY mythology. Did Tannock's aesthetic and indie history resonate with their Monorail ethos?

"We saw Craig as this ethical grassroots promoter who was always operating on a shoestring – he had this kind of anarcho-madness," Pastel laughs. "He's one of these people who just thinks things are possible. He was hoping to sell vegan shoes in here at one point. He's brilliant and bonkers."

Club Beatroot offered a collaborative snapshot of a certain place at a certain time (Glasgow underground, mid-late 1990s), echoed in a new box-set, Some Songs Side-By-Side, released this week by Tannock's new Stereo label, Downie's Watts Of Goodwill imprint and Stevie McCaffrey's likeminded RE:PEATER Records (see panel).

Downie launched Watts Of Goodwill in 2009 (his second release was the Scottish Album of the Year Award-nominated Muscles Of Joy LP) and Pastel has stellar label form: he ran iconic indie 53rd and 3rd (Jesus and Mary Chain, The Beat Poets, Talulah Gosh), and now co-helms Geographic (Lightships, Bill Wells).

Williamson, meanwhile, co-runs ethical label Ubisano, thus ensuring Monorail has an instinctive understanding of the ways in which record shops need record labels to thrive, and vice versa.

The shop has subtly charted an evolving sonic landscape over the past decade. "Russell [Elder] joining was really significant because he had really good metal knowledge," Pastel notes. "And when we opened in 2002, there was a sense of modernity about a lot of independent music – it was very much that era of Stereolab, Tortoise, quite forward-looking musicians – whereas, at this point in time, there's more great retro music, like Crystal Stilts and Veronica Falls.

"Listening and buying habits have become wilder too, because people can check anything out online."

Has the wealth of exotica championed by Monorail or available in cyberspace had a discernible impact on Glasgow bands? "A group like Sacred Paws wouldn't sound like they do without all those incredible African reissues – bands are exposed to far more exotic things now," suggests Pastel. Sacred Paws' entrancing tropical (post-)punk graces Some Songs Side-By-Side, and they'll also play Monorail's birthday hoopla on Sunday, along with Richard Youngs, Moon Unit and a rumoured rare turn from The Pastels.

Monorail, 12 Kings Court, Glasgow. Open 11am-7pm Monday-Saturday; noon-7pm Sunday. The shop's 10th birthday party is on Sunday, 7.30pm. Free advance tickets from Monorail.