A business system shaped around your shop

Open-source retail ERP.
Shaped around your shop.

Run Mosaic on the shop PC, or host it securely to check the shop from anywhere on a phone. Mosaic is a self-hosted retail ERP for inventory, purchasing, sales and core accounting. Answer plain-English questions about how your shop works, and Mosaic configures the working system for your stores, channels, stock, credit, returns, staff and tax registration.

The real Mosaic Today screen for the demo store Northstar General Store, showing stock on hand, today's sales, recent bills and the next steps for the day
One questionat a time
22tax jurisdiction guides
2 installersWindows and Apple Silicon Mac
Your dataexportable and self-hosted
Step one

It starts with a conversation.

No forms to decode, no consultant required. Mosaic asks plain questions about your products, stores, channels, stock, credit, returns, staff and tax registration, one at a time, with the reason for every question explained.

The real Mosaic owner interview asking one plain question at a time, with the reason for the question shown alongside
The real owner interview in Mosaic v1.3.2 - one plain question at a time, with the reason explained
Mosaic summarizing what it understood about the business and explaining why each feature is enabled, before anything goes live
Every enabled feature comes with its reason
Step two

Watch it become your system.

Each answer configures the real thing: modules, workflows, roles, controls, reports, terminology, even branding, in the running ERP rather than a plan for one. Mosaic shows you the summary and explains why every feature is enabled before anything goes live, and configuration versions can be reviewed, explained and rolled back.

Step three

Run the day from one place.

Mosaic connects everyday retail work to the core accounts while keeping access, changes and exceptions visible.

The configured Mosaic retail workspace for Northstar General Store, showing today's sales rung up from live stock
The configured workspace, shaped by the interview - everyday sales rung up against live stock
Step four

Change things by asking.

Later changes do not need a settings maze. Built-in chat answers plain questions from your live data, and handles configuration in plain words - showing the exact change for review and applying it only after you confirm. Nothing changes on its own, and applied versions can be explained and rolled back.

The built-in Ask Mosaic box with the plain-English question Show low stock, answered deterministically from live stock data
A plain question, answered deterministically from live data
A normal day

What a normal day can cover.

Mosaic runs the tested core retailer flow, with plain screens for the owner and team.

Morning

See what matters

See the core numbers that matter: stock, cash, supplier bills, aging, trial balance, profit and loss, and balance sheet.

During the day

Keep work moving

Raise and approve purchases, receive stock, sell with exact tenders, process returns, move and count stock, and close cash.

When things change

Stay in control

Add a store, staff role or reviewed configuration change with an audit trail. Reconcile bills, payments and the bank, then lock a closed period.

Release boundary: v1.3.2 covers the tested production core for retailer operations and core accounts. It does not claim statutory invoice formats or filing, advanced retail/manufacturing/payroll modules, managed hosting, or certified operator recovery and availability.
Retail ERP coverage

Inventory and accounting ERP for one store or many.

Use one self-hosted system for multi-store retail inventory, purchasing, receiving, sales, returns, supplier bills, bank matching and core accounting reports. The owner interview configures the working ERP without requiring custom code.

Fit the system to the shop

Grocery, fashion, electronics, pharmacy, beauty, specialty retail, services, multiple stores, online channels, credit, expiry, and warranty needs change how Mosaic configures your system.

Choose how chat works

Built-in deterministic chat is the default. You can connect your own AI provider, with setup and configuration guided in chat. Secrets use a masked secure step and never enter chat, logs, exports, or audit detail.

Build dashboards in chat

Ask for dashboards and supported reports in plain language. Mosaic creates a reviewable definition from allowlisted business data, never unrestricted SQL.

Give staff safer access

Give staff only the actions, locations, amounts and record states they need. Sessions and invitations are revocable, and changes are audited.

Reduce repeated handoffs

Carry approved purchases, sales, returns, supplier bills, payments and bank matches into an immutable double-entry record and core reports.

Handle tax questions carefully

Country-specific questions, source links, dates, and warnings help uncover facts that cannot safely be guessed. Professional review still matters.

Keep control of the information

Export your workspace, self-host the software and use the included local backup/restore path. Production recovery and availability remain the operator's job.

Start without a licence fee

The source is MIT licensed. Hosting, implementation, migration, operations, and professional advice can still cost money.

Tax guidance

Guidance for 22 tax jurisdictions.

Mosaic asks the business facts each location needs and keeps official source links and dates with the configuration.

IndiaUAESingaporeChinaVietnamMalaysiaUKUSACanadaEuropean UnionAustraliaNew ZealandJapanSouth KoreaSaudi ArabiaSouth AfricaBrazilMexicoIndonesiaPhilippinesThailandSwitzerland
These are configuration guides, not tax filings, certification, legal advice, or tax advice. The owner can verify the reviewed configuration; professional review is recommended.
How a business owner starts

Use the shop PC, or check the shop from anywhere.

The desktop installer keeps Mosaic on the shop PC. A hosted HTTPS install opens the same responsive ERP in a phone browser; there is no separate mobile app. Kubernetes remains a professional production path.

1 · Choose shop PC or hosted access

Use the desktop installer for the shop PC, or follow the hosted guide for secure phone access. Create the owner account in the browser; no workspace or API key is shown to ordinary users.

2 · Describe the business

Work through plain questions about products, stores, sales channels, stock, credit, returns, services, staff, tax registration, and optional AI-provider setup. Configuration stays chat-guided; provider secrets are entered only in a masked secure step.

3 · Watch each answer change the system

See Mosaic configure real workflows, reports, roles, verification tasks and business terms from every answer.

4 · Bring in the right people

Review the planned controls with staff. The owner can verify tax and generated reports in one click; professional review is recommended.

5 · Save, explain, and undo

Keep configuration versions and audit history, and roll back configuration when a reviewed choice needs to be reversed.

6 · Export and keep control

Use the configured system for its tested core retailer work and export the workspace when needed. Stay within the stated release boundaries.

Questions

Questions a business owner may ask.

Straight answers about what Mosaic can do today and where production help may be needed.

Can I try it without an IT team?

Yes. Download the Windows or Apple Silicon Mac installer and Mosaic opens in your browser. A guided local trial with Python 3.10+ and two commands also works. Kubernetes production deployment needs professional help.

Will it fit my type of shop?

The configured system changes for major retail types, stores, online channels, credit, returns, expiry, warranty, services, and staff patterns.

Can it bring in my existing products and parties?

The validated migration flow supports products, customers, vendors, stock and reviewed open documents. Mapping, reconciliation and opening balances still need review before applying.

Can stores and staff have different access?

Yes. Operational access can be limited by action, location, amount and record state, with revocable sessions and an audit trail.

What accounting work is included?

The tested core includes supplier bills and payments, bank matching, immutable double-entry journals, period locks, aging, trial balance, profit and loss, and balance sheet. Chat can create reviewed draft statutory invoice definitions and other reports from allowlisted business data. Statutory output remains review-gated and filing is excluded.

How does it handle tax?

Candidate calculation packs stay disabled until the owner or a named professional verifies the exact jurisdiction, dates, sources, rules and regression cases. Statutory outputs and filing remain disabled separately.

What if the internet fails?

The core local Mosaic app and its built-in deterministic chat run on the same computer without internet after download. This is not an offline AI claim: the optional local assistant Preview also runs on the same computer once its pinned model is downloaded (about 1.2GB, peak memory about 2.1GB). A connected AI provider, hosted setup, or multi-store setup depends on the chosen provider, network, and infrastructure.

Who owns the data?

In a self-hosted setup, the business controls its environment. Mosaic supports configuration export, workspace export, backups, and confirmed deletion.

How do backups, upgrades, and support work?

Backup/restore tools and runbooks are included. There is no promised managed support service. The business owns operations and should use professional platform help for production.

Can I check the shop from my phone?

Yes. Host Mosaic behind HTTPS and open the responsive web UI in the phone browser. There is no separate mobile app. The desktop installer stays private to the shop PC.

Should a professional be involved?

Professional review is recommended for tax and accounting. Kubernetes production deployment needs professional platform help; owners can run the Docker Desktop trial themselves.

How much migration work is required?

It depends on current systems and data quality. Mosaic stages and validates supported core records, but mapping, reconciliation and reviewed opening balances still need implementation work before a switch.

What does it cost?

The source is MIT licensed with no software licence fee. Hosting, implementation, migration, operations, and professional advice can still cost money.

What is complete today?

The source-tested v1.3.2 candidate covers guided setup, built-in deterministic chat, optional bring-your-own AI-provider setup, core purchases, receiving, sales, exact payments, returns, stock, cash, supplier bills/payments, bank matching, period close and core accounting reports. New in Preview: the fine-tuned local assistant can understand, draft and explain ERP actions, and every action stays behind the owner's explicit confirmation of the exact rendered payload. Preview quality is bounded and measured on the frozen development contract: all constrained outputs were schema-valid and every tested unsafe request failed closed, while label accuracy was 84 to 86 percent, so drafts must be read before approval. Its other explicit exclusions still apply.

For a production team

Details for a production team.

Business owners can stop above. These links and checks help a technical evaluator plan a production environment.

Deployment choices and verified checks

The local trial uses SQLite. Production packages use an external PostgreSQL service through Docker Compose or Kubernetes/Helm. The v1.3.2 source passed fresh application/security, PostgreSQL 17 tenant-isolation, strict Helm, deployment-validation and live container-readiness checks, plus native amd64/arm64 availability benchmarks for the local assistant Preview (two-stage constrained decoding against the frozen intent contract). Fresh tagged images, signatures, software inventory/provenance and vulnerability results remain required before publication.

Deployment guide · Architecture and limits · Product and publication-parent checks · Pages deployment

What remains the operator's responsibility

Real DNS and encrypted connections, managed PostgreSQL availability and recovery, offsite backups and restore drills, load and failover testing, identity-provider setup, monitoring, incident response, and an independent security assessment before real financial-data use.

Download

Get Mosaic ERP free.

Open source under the MIT license. Mosaic runs on your own computer and your data stays with you.

Windows may show a SmartScreen warning. This early Windows app is not code-signed yet, so Windows can show a blue "Windows protected your PC" screen. Choose More info, then Run anyway. Mosaic then opens in your browser at a private localhost address, and your data stays on your computer.

Mac may say the app cannot be checked for malicious software. This early Mac app is not signed with an Apple Developer ID yet, so Gatekeeper can block the first open. Open the downloaded dmg, drag Mosaic ERP to Applications, then right-click the app and choose Open, and confirm with Open in the dialog. You only need to do this once. The Mac app is for Apple Silicon (M1 and later); on an Intel Mac, use the guided install below.

Everything is included, including the assistant. On first run Mosaic downloads the optional local assistant model (about 1.2 GB) in the background - the whole ERP and the built-in deterministic chat work while it downloads, and the assistant runs fully offline afterwards. Allow about 3 GB of free RAM when the local assistant is on.

Linux and Intel Mac users: the guided install works today - install Python 3, download the source, and run two commands. Follow the guided install.

Review the v1.3.2 release.

Start with the two-command local evaluation. Use the source and evidence to plan a properly operated PostgreSQL production rollout.

Follow the build

Mosaic updates from Hearthplug.

Product walkthroughs, release notes and real retail workflows from the team building Mosaic ERP.