Invite codes no longer gate your own accounts. Bring-your-own-account use is free for everyone; cloud Pro stays invite-only.Read the announcement
AnnouncementAugust 9, 2026

To everyone who's been following or using Mirasim:

Over the past few days, Mirasim ended up in front of a much bigger audience much earlier than we'd planned. We were still in private beta and, honestly, nowhere near ready for a wider launch.

Invite codes spread far beyond the small beta group we had planned for. In a very short window, we saw a flood of visits and test requests, along with some unusually aggressive, probing request patterns. Our capacity, reliability, and security systems weren't ready for that volume. Some of you ran into slow loading, failed requests, or Pro benefits that never showed up.

We're genuinely sorry for the rough experience. Whatever the source of the traffic, we should have been better prepared. That's on us, and our users shouldn't have to pay for it.

At the same time, you sent us a huge amount of honest, detailed feedback. A lot of issues that probably wouldn't have surfaced until a public launch showed up early. Thank you to everyone who took the time to try Mirasim, patiently share feedback, or report security issues responsibly.

Here's how access to Mirasim will work from here

Invite codes no longer limit connecting your own accounts to Mirasim — they only limit the cloud Pro service that Mirasim pays for.

Connecting and using your own accounts locally will be free for everyone. You'll be able to connect the Claude Code, Codex, and other model accounts or services you already use, then work across multiple models, Agents, and sessions in Mirasim. Mirasim won't charge for any of this. Third-party subscription or API fees will still follow each provider's own terms.

Cloud Pro access — where Mirasim covers the model usage costs to make things cheaper for users — will remain invite-only and roll out in batches as capacity allows. We'll keep sharing our progress and what opens next, so the rules stay as clear and transparent as possible.

A note on Pro benefits

  • The 1,000 beta users covered by our original promise will still receive one full year of Mirasim Pro. That promise has not changed.
  • Anyone who successfully registered during this wave after we had already passed the original 1,000-user limit will receive one month of Mirasim Pro. This is both to make up for the unstable experience and to thank you for trying Mirasim before it was fully ready.
  • If you've already registered or activated your access but your Pro benefits still aren't showing up, please don't try again. We have the records. We'll verify eligibility and apply the benefits in batches, then share the timing and start-date details.

How the rollout will work from here

Over the next week or two, we'll focus on adding capacity, fixing the entitlement system, tightening security, and working through your feedback one issue at a time. Mirasim remains open. Registration and local, bring-your-own-account access will stay available, while cloud Pro access will roll out in batches as capacity allows.

We're not trying to build yet another model aggregator. We want Mirasim to be an Agent workspace you can keep building in for the long run. Wherever the next leap in Agent capability comes from, you should be able to plug it into the same workflow, switch seamlessly, and use different Agents together. Once you've built something, you can put it in front of simulated users in a real environment and let evidence — not guesswork — tell you what to do next.

We want every leap in what Agents can do to become real leverage for everyone — so you spend less time chasing tools and more time building what you actually care about.

Models will change. You shouldn't have to start over.

Thank you for showing up before Mirasim was fully ready. From here, we'll put these promises into every fix and every update, and work to earn your trust by making Mirasim more stable and more reliable.

— The Mirasim team

Mirasim
Get helpGet Mirasim

A build space where progress can listen.

Agents can write a great deal of software very quickly. What they cannot do on their own is tell you whether any of it was worth writing. Mirasim puts both halves in one space: the agents that build, and the simulated users who try the result and say where it fails.

Get Mirasim
01

Agents build.

Up to six agents work in parallel panes, each in its own git worktree: Claude Code, Codex, and Mirasim's own. A full editor, terminal, file tree and artifact store sit in the same window.

02

Simulated users try it.

Hand a build to a simulated person and they work through the job on a real browser, phone or shell, clicking what they'd click and giving up where a real user would give up.

03

Evidence decides.

Every run comes back scored against a fixed rubric, and every number links to the moment that produced it. Keep the change or roll it back on what the runs say, then go round again.

Why a loop, and not a faster editor

The bottleneck in building a product stopped being the typing some time ago. It is knowing which of ten plausible directions a real person would actually follow, and that answer normally arrives weeks later.

A simulated user closes that gap to minutes. Not because a simulation is the same as a launch, but because most of what you need to learn early is coarse: the step nobody finishes, the wording nobody understands, the button nobody finds. Those show up in a simulated run, they show up cheaply, and they show up before the work is sunk.

So the unit of progress here is not a commit. It is a round: build, put it in front of people, read what happened, keep what won.

Everything shown is real

Every recording and screenshot on this site comes from the shipping product on a real workspace. Nothing here is a mock-up or a re-enactment, even when a real capture is the less flattering one.

Evidence over opinion

An evaluation is only worth something if it can be wrong. Runs are scored on a rubric fixed before the run, and reports link back to the traces they came from.

Your stack stays yours

Your subscriptions, your API keys, your models. Swap them mid-build, add MCP servers, run models locally. Nothing forces you onto one provider.

Invite-only

A code gets you in.

Mirasim is invite-only for now. The code costs nothing, and everything that runs on your own model accounts runs from day one. Invites buy months of a paid plan: 3 people who actually use it gets you a month of $29/mo, 5 a month of $149, 10 a month of $379.

See how it works
Get in touch

Questions about the product or working together: support@mirasim.ai. We read everything that arrives there.