AI already writes your software.
Tandem actually makes it predictable.

Tandem keeps one living model of how your business works. The journeys, the events, the rules. Your AI tools build from it, and what they build gets checked against it. Your software stays maintainable long after it was built.

Get early access Currently in private beta. Early access opens later this year.
Recruiter creates a new candidate
01 Candidate enters the system
Intake mailboxCV uploadCandidate creation
02 Confirm who this is
Possible match checkPossible match check
03 Check the draft profile
Candidate profile (draft)Candidate read
04 Candidate is in the pool
Candidate profileCandidate pool
Commands
Check for duplicate
Approve draft profile
Preconditions
CV contains a name and an e-mail address
Events
CV received
Draft profile approved
Candidate added to pool
01 — The problem

Building was never the bottleneck

Validation became the job

The build takes an afternoon. Working out whether it does what you meant takes the rest of the week, every time, because there's nothing to check it against.

“The build process is trivial, anyone can do that. The validation process is what counts — that's where 90% of your time goes.”

— IT lead, staffing group
One feature, one week
Build an afternoon
Validation the rest of the week — by hand, every time
Nothing to check it against, so someone checks it by hand.

The reasoning disappears

Six months later nobody can say why it works this way. Not the person who prompted it, not the supplier who shipped it. The decisions were real. They just lived in a chat window.

Chat6 months ago
Only enable Save once the client is approved.
Done. I also moved the approval check to the API layer.
Why there?
Cleaner that way.
The decision was real. The record of it wasn't.

Changes break things sideways

A deploy lands and a save button stops working, a view comes back empty. The core logic holds; the edges quietly don't. You hear about it from a user.

Clients Save
Something went wrong.
TypeError: Cannot read properties of undefined (reading 'id')
Reported by a user · 11:26Retry
Deploy #214 landed · 09:41
02 — The product

One model.
Everything is built from it.

Every AI tool guesses at how your business works. Tandem writes it down once: a model your team can read and your AI tools build from directly. It stays true as your business changes.

Layer 1

Journeys

Start from what someone is trying to get done.

A goal in your people's words, split into the stages they actually go through. No system terms, no screens yet. Just the work.

Layer 2

Surfaces

Every stage gets a surface.

A screen where a person does the work, or a capability for what their AI agent does. Named up front, so nothing shows up later as a surprise.

Layer 3

Events and rules

What your business records, and what it won't allow.

Based on event sourcing principles, we write down the events each stage produces, and which rules decide what is allowed. Nothing gets overwritten: every change is stored as a fact, in order, so today's state can always be traced back to what produced it.

Journey
Recruiter creates a new candidate
Layer 1 of 3
Stage
01Candidate enters the system
02Confirm who this is
03Candidate is in the pool
Surface
Intake mailbox CV upload Creation form Candidate creation
Match check Match check
Candidate profile Candidate publish
screen capability (agent)
Commands
UploadCv
CreateManualProfile
ConfirmSamePerson
ConfirmNewPerson
MarkCandidateReady
Pre­conditions
ProfileQuotaTotal
MatchDecisionPending
ProfileNotAnalyzing
RequiredFieldsPresent
Events
CvUploaded
ManualProfileCreated
SamePersonConfirmed
NewPersonConfirmed
CandidateReady
command precondition event

Built from the model.
Checked against it.

The model does two jobs. Your AI tools build from it, and everything they build gets checked back against it. Ask an AI the same question twice and you'll get two answers; the model is what decides which one is right. When code and model drift apart, a check fails, and you hear about it before your users do.

Model
Recruiter creates a new candidate
3 stages · 8 surfaces
5 commands · 5 events
builds
checks
Code
markCandidateReady(profile)
  require RequiredFieldsPresent
  emit CandidateReady
Building from the model…
03 — Ownership

Yours to take with you

The model and the code are yours from day one, in your repository, in a format you can read without us. Leave when you like and take both. The only thing you give up is what keeps them in sync.

04 — FAQ

Questions we hear most.

A map: the journeys people go through, the surfaces they use, and the events underneath them. Your team reads it, and so do your AI tools.

No. You describe how your business works and the AI drafts the model from that. You read it back and correct it.

Markdown files are a snapshot somebody has to keep rewriting. They drift, and no one notices. The model is structured, stays current, and is what the output gets checked against, so drift becomes a failing check instead of a surprise six months later.

Then it's for them. It's what their tools build from, and what their reviews check against.

Yes. Context reduces it, the checks catch what's left, and review stays part of the process.

You change the model. The software follows from it, and the change is on the record.

It's the technical design pattern we build on. Instead of overwriting the current state, your software keeps every change as a fact, in order, the way a bank keeps transactions and derives the balance. History and audit trails come for free.

Wherever you want: your own infrastructure, or hosting we provide on European servers.

Your model and your data stay yours, on European servers. We don't train anything on them.

You take the model and the code and go. Both are yours from day one, in your repository.

Private beta. You can sign up for early access now.

Build with AI. Stay in control.

We're designing Tandem with a small number of companies that build software with AI and want to stay in control. We have a few spots left for early access.

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