Source-available transaction integrity engine
Declare your economy.
Meridian runs it.
A Kubernetes-style manifest declares your instruments, accounts, pricing and settlement. Meridian operates it — durable sagas that complete or compensate, on a double-entry ledger that can explain every penny, kilowatt-hour, and carbon credit.
Every company becomes a financial company. Few mean to.
It never happens all at once. It happens one reasonable sprint at a time.
A checkout and a cron job
Stripe takes the card. A nightly script tots it up. Done, you think.
Usage metering
Pricing goes per-seat, then per-event. Someone builds a counter table.
Revenue splits
Partners want their cut, automatically. The cron job grows branches.
The audit
"Show us the transaction trail." There isn't one. There are logs.
You run a financial system
Unreconciled, undocumented, load-bearing. And it was never the product.
Meridian is the financial system you were always going to end up building — already built, audit‑grade, and declared rather than accreted.
Infrastructure went declarative. Money didn't. Until now.
Kubernetes taught a generation that you don't script servers into existence — you declare the state you want and a control plane keeps it true. Meridian applies the same idea to value: the manifest is the running system.
Declared, not coded
Instruments, account types, valuation rules and settlement sagas in one YAML document. Applying it is the deployment — no PRs to Meridian core, no migrations.
Operated, not provisioned
Meridian doesn't just create the configuration; it runs it. Scheduled billing fires monthly. Settlement triggers when market data lands. Failed steps reverse themselves.
Writable by AI, safely
Because the format is constrained and schema-checked at compile time, an AI assistant can draft a working economy in conversation — and the manifest can only call real handlers with real types.
# A parimutuel betting platform: pooled stakes, market-data
# settlement, 15% commission, Stripe Connect payouts.
instruments:
- code: BET_UNIT
type: INSTRUMENT_TYPE_VOUCHER
accountTypes:
- code: SYNDICATE_POOL
normalBalance: NORMAL_BALANCE_CREDIT
policies:
validation: "amount > 0"
bucketing: "attributes.syndicate_id"
- code: BET_POSITION
normalBalance: NORMAL_BALANCE_DEBIT
allowedInstruments: [BET_UNIT]
- code: PLATFORM_COMMISSION
normalBalance: NORMAL_BALANCE_CREDIT
valuationRules:
- name: bet_unit_to_gbp
method: VALUATION_METHOD_FIXED
sagas:
- name: create_syndicate
- name: join_syndicate
- name: settle_syndicate
trigger: event:market-information.observation-recorded.v1
- name: refund_syndicateAbridged from a real cookbook pattern — the full platform is under 400 lines. Read the whole thing →
Durable execution — with the books built in.
Workflow engines can promise your workflow finished. Meridian promises something stronger: the ledger agrees it finished. Every multi-step movement of value either completes, or its compensations run backwards until the books balance again. No orphaned charges. No partial state. No 2am reconciliation spreadsheet.
Plain code, not a workflow DSL
Sagas are written in Starlark, the Python subset Google built for Bazel. Your team reviews them like any other code. No imports, no network, no filesystem — the runtime enforces step limits, so every workflow provably terminates.
Compensation is the contract
Each step declares how to undo itself. When the payment network times out at the final step, Meridian reverses every completed step automatically — and the audit trail records the whole episode, including the failure.
One ledger for everything your business calls value.
Underneath the manifest and the sagas sits a double-entry ledger that treats money, megawatts and carbon with the same rigour your bank applies to pounds.
Every asset, typed
Currency, kWh, CO₂e, compute hours, vouchers — native instruments in a single ledger, with type safety that refuses to add pounds to kilowatt-hours.
multi-asset · dimensioned unitsAudit-grade by construction
Double-entry posting with an immutable trail. When your auditor asks where the money went, the answer is a query — not an archaeology project.
immutable · bi-temporalData that knows its quality
Every measurement carries what was known and when. The quality ladder — Estimate → Coefficient → Actual → Revised — absorbs late and out-of-order data without locking the database.
estimate → actual · wash & reloadCollection included
Stripe Connect for multi-tenant payment collection, dunning escalation, refund compensation, and reconciliation that flags variances before your customers do.
stripe connect · reconciliationStart from a working economy, not a blank page.
The cookbook is a registry of vetted patterns — manifest fragments plus sagas — for whole business models. Copy one into your tenant, apply, and it runs. Browse them live inside the demo.
Tote (Parimutuel) Betting Platform
Syndicate-based parimutuel betting with pooled stakes, equal-entry bets tracked as voucher instruments, market-data-driven settlement, 15% platform commission, and Stripe Connect payouts via the Financial Gateway.
Energy Usage-to-Value Settlement
Converts metered kWh into monetary value using market rates. Creates retail and wholesale GBP positions from energy consumption.
SaaS Compute Billing
Usage-based billing for cloud compute resources. Meters GPU hours, API calls, and storage consumption, then converts to USD charges via valuation rules. Includes platform credits as a voucher instrument.
Carbon Credit Registry
Carbon credit trading and retirement with verified emission reductions (VERs) and certified emission reductions (CERs). Tracks credit provenance by vintage year and project, with a permanent retirement account for irrevocable credit retirement.
Dynamic Capacity Pricing
Self-referential feedback loop pricing for compute tokens. Bills token consumption at rates derived from the platform's own utilisation forecasts per data centre region. Usage patterns drive pricing, and pricing shapes usage patterns.
KYC Compliance Workflow
Initiates KYC verification when an individual party is created. Uses the compliance marker pattern: books a zero-amount position log to track outstanding KYC obligations per jurisdiction. Compliance accounts are resolved via entity graph traversal.
The whole engine, on your laptop, in one command.
Every service compiles into a single binary. Docker Compose brings up the full platform — ledger, sagas, web UI — with nothing to configure.
- Register customers, open accounts, watch postings hit the ledger
- Every operation runs as a saga with automatic compensation
- REST on
:8090, gRPC on:50051, UI on:5173
Source-available. Honestly priced. Eventually open.
You're trusting this engine with your books, so the terms are on the front page.
- Licence
- Business Source License 1.1 — read, modify, and deploy. The code is all there.
- Free in production
- Up to 5,000 active accounts across all tenants. Development, testing and evaluation are always free.
- Beyond that
- A commercial licence — ben@meridianhub.org
- And then
- Converts to Apache 2.0 on 12 February 2030. Worst case, you wait us out.
GogRPC + Protocol BuffersPostgreSQL / CockroachDBApache KafkaKubernetesStarlark + CELStripe ConnectOpenTelemetry
Design partners wanted
Have an economy that doesn't fit the billing tools?
Usage that arrives late. Value that isn't money. Splits that auditors will read. That's exactly what we built this for — and we're looking for a handful of teams to build alongside.