---
title: "composable, modular, open"
canonical_url: https://ensurance.app/guide/composable-modular-and-open
markdown_url: https://ensurance.app/guide/composable-modular-and-open.md
subtitle: "bundling or stacking is the credit world discovering composability, one committee at a time"
category: onchain
---

# composable, modular, open

*bundling or stacking is the credit world discovering composability, one committee at a time*

**Composability** is the property of a system whose parts other people can build on without asking. In finance it is mostly said of open ledgers, where one contract can hold, read or route another contract's token the moment that token exists, and nobody at the first contract has to sign off. The rest of this post is about why the credit world keeps arriving at the same question under another name.

Start with a coral reef. Colonies of small animals lay down limestone, and then everything else builds on it: fish that shelter in it, sponges and algae that grow on it, grazers that keep it clear. None of them asked the coral. When one grazer thins out, another often takes up part of its work, and the reef keeps going, at least for a while. The reef does all of this whether or not anyone issues a unit for it. [*Ensurance*](https://ensurance.app/?from=guide) funds the condition of a living system like that. It is not the reef.

Others build on the reef, one part can go without taking the whole, and no single colony can switch it off. Our bet is that money for living systems ends up shaped more like the reef than like paper.

:::johnson
**bundle or stack is a composability question, handed to a committee because the unit cannot answer it.**

A primitive lets the people who build on it choose the combination, while the place stays whole.

[use the parts beside the work you already do →](/guide/use-ensurance-beside-the-work-you-already-do?from=guide)
:::

## three words, in plain terms

### what is composability in finance?

Composability in finance means a unit, or a contract, that other systems can use without permission from whoever made it. A stablecoin is the familiar case. A wallet holds it, a lending market accepts it, an exchange pool trades it, a payroll tool pays it out, and none of those builders signed an agreement with the issuer to start. Decentralized finance calls this "money legos," and the idea belongs to the teams who built those open markets.

### what is the difference between composable, modular and decentralized?

| word | in plain terms | on the reef | the question to ask any unit |
|---|---|---|---|
| **Composable** | Others can build on it without asking | Fish, sponges and algae live on coral nobody licensed | Can a stranger use this unit in their own system tomorrow? |
| **Modular** | One part can be replaced without the whole | Another grazer takes up part of the job | If one part fails, or I do not want it, do I lose the rest? |
| **Decentralized** | No single party can stop issuance or transfer | No single colony runs the reef | Who can stop this unit from being made or moved? |

They are not the same. A system can be modular inside one company's walls and not composable at all. A stablecoin is composable, yet its issuer can usually block an address, which is the decentralization question. Ask all three, separately.

## the question the commission is asking of paper

On 7 July 2025 the European Commission published its roadmap towards nature credits. It sets up an expert group to advise on criteria and methods in 2026, aims at a certification framework by 2027, and runs pilots in France, Estonia and Peru. Covington's reading flagged a choice it leaves open. Should one credit bundle several services on a site, carbon and habitat and water, into a single unit? Or should each be stacked as a separate credit for a separate buyer?

### why does the eu nature credit roadmap ask about bundling and stacking?

Because a credit has to decide, before it is issued, what it is made of. A bundled credit holds many services, and a buyer who wants only the water gets the carbon too. A stacked set is many units cut from one site; each buyer gets exactly their service, and someone has to make sure the same hectare is not paid twice. Both answers are reasonable, and serious people are arguing both.

The answer has not landed yet. Bellona's account of the expert group's third meeting, on 18 May 2026, says the Commission presented bundling and stacking as a concept there, and Bellona argued that some forms should be restricted. On 7 October 2026, Carbon Pulse reported that the Commission is treating the period to the end of 2027 as an exploratory phase to test whether an EU-wide market can work. As of 21 October 2026 we could not find a published decision on bundling or stacking.

That is the composability question, asked of paper: which parts can be separated, which must travel together, and who decides. In a credit, a committee decides once, in advance. In a composable system the parts are separate from the start, and the people building on them choose.

On one parcel the stacking question has a practical answer, and [stack the buyers, not the acre](/guide/stack-the-buyers-not-the-acre?from=guide) gives it: many payors, one whole asset, no function sold twice. This post stays on the other reading, what the debate says about the unit itself.

## why a credit cannot compose

Give the credit its due first. A methodology says what counts. A verifier checks it on the ground. A registry gives the unit a serial number and retires it once. The claim, a tonne avoided or a habitat unit delivered, is what the buyer pays for. That care is real, and the binding is what makes the claim credible. Inside the registry's walls, it is what keeps the same tonne from being counted twice.

But the four are one object. The serial number means something only in the registry that issued it. The methodology cannot be swapped without issuing a new unit. The verifier's report belongs to that unit and no other. A system that wants to build on the credit, say a city budget that pays monthly or a fund routing a share to the people on the ground, has to open a registry account and accept its terms. That is permission, not composition.

None of this is a flaw in the people. It is the shape of an instrument built to be used once, by one buyer, against one claim. A committee asking whether to bundle or stack is asking how to cut a bound object, because nobody else can cut it. [A registry is not a market](/guide/a-registry-is-not-a-market?from=guide) takes the ledger side of that argument further.

## how the parts separate here

On this protocol each job is its own part, on a public ledger, following a standard other systems already read.

A **coin** is an **ERC-20** token, the common standard for a fungible token: each unit the same as the next, readable by almost any wallet, exchange or contract. The coin is currency.

A **certificate** is an **ERC-1155** token, a standard that lets one contract issue many token types, each with its own count. Here each certificate is 1:1 with a named agent. It is a record of a hold on that agent. It is not title, and it is not a claim on the place.

An **agent** is an **ERC-721** token, the standard for a one-of-one token, with a **tokenbound account**: a wallet that belongs to the token itself, so the agent can hold and send funds at its own address. The agent is the address for a place, a people or a purpose.

Three more parts route the money. A **pool** is the public market where a coin trades, open to any wallet. A **payout recipient** is the address a coin's trading proceeds go to, and it can be an agent's account. A **proceeds split** divides what arrives among several addresses by set shares.

| part | its job | usable without the others? |
|---|---|---|
| Coin | Currency that circulates in its pool | Yes. A coin can fund a theme with no certificate in sight |
| Certificate | A record of a hold on one agent | Yes. You can hold one without holding any coin |
| Agent with an account | The address for a place, a people or a purpose | Yes. An account can receive funds with no coin and no certificate |
| Pool | Where a coin trades | It belongs to its coin; any wallet can trade in it |
| Payout recipient | Where a coin's proceeds land | Any address, including an agent's account |
| Proceeds split | Divides what arrives | It can point at accounts that never touch a coin |

[`tresses`](/general/tresses?from=guide) is a coin named for a rare orchid of the Roaring Fork wetlands in Colorado. It trades in its own pool, and its payout recipient is the account of [`colorado-headwaters.syndicate`](/colorado-headwaters.syndicate?from=guide), an agent that exists whether or not the coin trades. Four parts, each usable alone. The orchid is in none of them. It is in the wetland.

None of these parts is a claim on the wetland, the reef or the land under either. Nothing is owed by the place, and nothing can be seized from it. Why there are three instruments and not one is its own page: [form follows function](/guide/form-follows-function-the-agent-the-certificate-and-the-coin?from=guide).

Modular means a group can take some parts and leave the rest: a carbon developer can give a stand an account and keep selling the tonne ([use ensurance beside the work you already do](/guide/use-ensurance-beside-the-work-you-already-do?from=guide)). Composable means a stranger can too: an outside one-of-one token can be given a tokenbound account without asking us, and any wallet can trade in a coin's pool ([the protocol door stays open](/guide/the-protocol-door-stays-open?from=guide)).

## decentralized, honestly

**The contracts are open after deploy.** A coin, a certificate or an agent's account that exists stays on the chain. The app can decline to feature something; it cannot delete a deployed contract. Not every setting is fixed: the factory owner can still change the terms for the next group namespace.

**A person confirms each action today.** An agent's account can propose a swap or a deposit, and nothing moves until a person confirms the card ([the account proposes. you confirm.](/guide/the-account-proposes-you-confirm?from=guide)). Decentralized does not mean unattended.

**The protocol is small.** On 21 October 2026 the coin catalog listed 192 coins, 100 of them with a pool address, and the account catalog listed 2,085 agent accounts, 86 with a wallet deployed. Volumes are small, and the protocol is its own first user. Decentralization is a property of the contracts here, not yet of a crowd.

So the honest score is mixed: composable by the standards, modular by design, decentralized at the contract layer with a person in the loop on purpose. [A credit judged as money](/guide/a-credit-judged-as-money?from=guide) scores every unit on the same rows, ours included.

## take the parts you need

Take the parts you need. Leave the rest. That sentence is the whole difference between a credit and a primitive.

The Commission is right to ask whether to bundle or stack. Our bet is that the money which pays the land, and the people who keep it, ends up composable, modular and open, because that is the shape the question is already reaching for. A committee answers it once for everyone. A primitive lets each group answer it for the place it knows, while the reef stays whole.

If you run an onchain group, see which parts fit at [onchain groups](/solutions/onchain-groups?from=guide&topic=money-that-acts-like-nature). If you fund places through grants, start at [foundations](/solutions/foundations?from=guide&topic=money-that-acts-like-nature). To see what is live first, [explore](/explore?from=guide). To talk it through, [talk to someone who can help](/contact?from=guide&topic=money-that-acts-like-nature).

## sources

[European Commission, roadmap towards nature credits, COM(2025) 374, 7 July 2025](https://ec.europa.eu/newsroom/env/items/892839) — the roadmap: expert group, pilots in France, Estonia and Peru, certification framework by 2027

[Covington, an EU biodiversity market by 2027: the new EU's roadmap towards nature credits, 8 July 2025](https://www.covingtonblogs.com/2025/07/08/an-eu-biodiversity-market-by-2027-the-new-eus-roadmap-towards-nature-credits/) — the bundling versus stacking design question and the mid-2026 expert group timeline

[Bellona, takeaways from the 3rd Expert Group meeting on Nature Credits, 29 June 2026](https://eu.bellona.org/2026/06/29/takeaways-from-the-3rd-expert-group-meeting-on-nature-credits/) — bundling and stacking presented at the 18 May 2026 meeting; Bellona's position

[Carbon Pulse, nature credit market remains open question as EU Commission tests demand, metrics, 7 October 2026](https://carbon-pulse.com/558059/) — exploratory phase to the end of 2027 (subscription)

[ensurance coin catalog](https://ensurance.app/api/general) — read 21 October 2026: 192 coins, 100 with a pool address; `tresses` pool and payout recipient

[ensurance account catalog](https://ensurance.app/api/accounts) — read 21 October 2026: 2,085 agent accounts, 86 with a wallet deployed

## the series

1. [every credit is trying to become money](/guide/every-credit-is-trying-to-become-money?from=guide) — the pillar
2. [a credit judged as money](/guide/a-credit-judged-as-money?from=guide)
3. [a registry is not a market](/guide/a-registry-is-not-a-market?from=guide)
4. [money that acts like nature](/guide/money-that-acts-like-nature?from=guide)
5. [composable, modular, open](/guide/composable-modular-and-open?from=guide) — this post
6. [pay the land, pay the people](/guide/pay-the-land-pay-the-people?from=guide) — the flag