Matthew Brue and David Butler knew pretty quickly they were onto something when they wrote “Middle Fingers,” the song that would be Missio’s breakthrough hit in 2017. A defiant anthem for disaffected youth, the song launched the Austin duo into the national spotlight, even though they’d barely played any live shows yet.

“I remember it very clearly,” Brue says. “The minute that song went up (on the internet), I started getting email after email after email from different labels, booking agents, publishers. At that moment, we were like, OK, something’s going to happen.”

Missio eventually signed with RCA Records, which released the duo's debut album “Loner” in the spring of 2017. National tours followed, along with an appearance at the Austin City Limits Music Festival that fall. It was a huge jump for a group that got started simply “as an internet band,” Butler says. “We got picked up by a lot of international blogs early on, and that’s how we got our footing.

“We never built from like the old-school kind of model of like, ‘Start playing shows in your hometown, develop a fan base there,’” Butler continues. “The electronic scene in Austin is still kind of in its baby stages; there’s not a lot of what we do going on. So it wasn’t a no-brainer to go out and play the shows first.”

The success of “Middle Fingers,” which hit the top 20 of several Billboard singles charts, helped pave the way for Missio’s second RCA album, “The Darker the Weather // The Better the Man.” Released in April, it feels like a significant step forward for the duo. “Middle Fingers” was a catchy song with a good video, but it was just novel enough that Missio could have been written off as a one-hit wonder. The new album overrides any such concerns.

There’s still plenty of in-your-face bravado on tunes such as “Temple Priest” (which features guests Paul Wall and Kota the Friend) and “Audi A4,” which celebrates blasting music loud in the car. But on “Rad Drugz,” Brue and Butler dig deeper, offsetting the song’s instant-party groove with an addict’s realization of the damage drugs are doing.

It’s also about more than just chemical addictions. “As an ex-drug-user myself, I always got really frustrated when people would make some drugs worse than others,” Brue says. "Drugs don’t necessarily mean just heroin or cocaine or meth or whatever. It actually could be your cell phone, it could be social media, it could be Netflix.

“So when we sing, ‘Your mama does drugs, your daddy does drugs, everybody does drugs’ — it’s very true, we’re all addicted to something. We like to make people think a little. When we released that as the first single, we didn’t really know how people were going to react to it. But it seemed like people got the message. There was a bit of conversation around it, which was the goal.”

Missio also is clearly interested in transcending genre barriers. Austin hop-hop act Blackillac guests on groove-heavy “Shimmy,” and new single “I See You,” an instantly memorable pop tune with an upbeat message, has racked up 2 million YouTube views.

On “Do You Still Love Me Like You Used To,” a guest vocal from Patty Lynn of local duo the Wind + the Wave steers the song in an almost folk-pop direction that’s strikingly different from anything else Missio has done. Getting Lynn on the track was an easy call because her duo partner, producer Dwight Baker, worked on both Missio albums.

Baker’s ties to the group are close enough that Brue and Butler say he’s like a nonperforming third member of the band. “He’s kind of like the Wizard of Oz, the man behind the curtain,” says Butler, who’d done lots of studio engineering and production work with Baker before Missio started. “He’s been my mentor for awhile, so it’s cool to get to share this with him.”

Brue and Butler met a few years ago while they were both playing in other bands, but after those projects ended, “Matthew started writing a solo project, and he came to me to produce it,” Butler says. "We became roommates, and that spurred the whole creative experience, because we were in the same place writing together.”

The two submitted a fully completed record to RCA for their debut. The label allowed them plenty of artistic leeway in making the second album. “We essentially just went out to El Paso for weeks by ourselves and did whatever we wanted to do,” Butler said.

If “The Darker the Weather” feels like a statement of growth for the duo, they say that wasn’t necessarily intended.

“Maybe not so much in the moment,” Butler says. “I think as we listened back, having finished all the songs, we can see the areas that have changed and grown. But as we were doing it, I don’t think there was a conscious effort to try to change what we did too much. We were just trying to be songwriters and trust our instincts.”

Brue adds, “Our goal in Missio is to always be pushing bounds, just for ourselves — seeing what weird things work, and trying new things out. So a lot of it was just experimenting with different things, and trying to focus more on stronger lyrics and stronger melodies.”

Partly, the new record reflects Missio’s resistance to being pinned down to any specific genre. “I think we both have a pretty hands-off approach to labeling anything,” Brue says. “We don’t tie ourselves to any specific instrument or tone or form of writing. For us, it’s always about the song, and trying to figure out the best way to say whatever we’re trying to say.”

That said, the big waves they’ve made so far give them hope, along with Austin duo Survive’s popular theme to Netflix's "Stranger Things," that the city could become more widely known for electronic-based music.

“It makes me stoked, for real,” Butler says. “I think Austin’s a pretty special place for creativity, but I’ve always thought that it could have more mainstream artists than it did. Hopefully that’s a good growing trend.”