# Lago vs Metronome

> Metronome scores 69.7 (B) to Lago's 65.7 (B) for usage billing. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/lago-vs-metronome
- Markdown: https://www.anchorterminal.com/compare/lago-vs-metronome.md (~2,400 tokens)
- Slim: https://www.anchorterminal.com/compare/lago-vs-metronome.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/lago-vs-metronome.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Metronome scores 69.7 (B) on agent readiness against Lago's 65.7 (B), and leads in 4 of 7 scored categories. Lago leads on reliability, payments & pricing and maintenance & community. Both do usage billing.

- Lago: grade B, 65.7/100, rank #311 of 950. Markdown https://www.anchorterminal.com/tools/lago.md · JSON https://www.anchorterminal.com/api/v1/tools/lago.json
- Metronome: grade B, 69.7/100, rank #173 of 950. Markdown https://www.anchorterminal.com/tools/metronome.md · JSON https://www.anchorterminal.com/api/v1/tools/metronome.json
- Best payment and monetisation platforms for AI agents: https://www.anchorterminal.com/best/payment-platforms/index.md
- All 76 platforms comparisons: https://www.anchorterminal.com/compare/payment-platforms/index.md

## Which one, for what

### Lago (B)

Good for: A team that wants usage metering, plans, wallets and invoicing under its own control and can run PostgreSQL and Redis.

Ahead on:
- Reliability, 86 against 68
- Payments & pricing, 50 against 39
- Maintenance & community, 91 against 82

Also in its favour:
- Open source

Watch for: The free edition has one organisation API key with full access. Creating more keys needs a Premium licence and per-resource permissions need an enterprise add-on

### Metronome (B)

Good for: A company that meters usage and bills on contracts, credits and commits, with invoices delivered through Stripe, NetSuite or cloud marketplaces.

Ahead on:
- Security & auth, 68 against 37
- Transparency & trust, 65 against 59

Also in its favour:
- A hosted endpoint, with nothing to install
- No incidents deducted, where Lago loses 3 points for them

Watch for: Errors are a single `message` string with no machine-readable code, and the API description documents a 4xx response on 87 of 142 operations


## Score by category

| Category | Weight | Lago | Metronome | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 86 | 68 | Lago +18 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 87 | 88 | Metronome +1 |
| Agent ergonomics | 13% (16.2 this run) | 71 | 75 | Metronome +4 |
| Security & auth | 14% (17.5 this run) | 37 | 68 | Metronome +31 |
| Payments & pricing | 10% (12.5 this run) | 50 | 39 | Lago +11 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 91 | 82 | Lago +9 |
| Transparency & trust | 7% (8.8 this run) | 59 | 65 | Metronome +6 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **65.7 · B** | **69.7 · B** | |

## Facts side by side

| Fact | Lago | Metronome |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Get Lago Corp. | Metronome (Stripe) |
| Hosted endpoint | no (local only) | `https://api.metronome.com` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Pay per use |
| x402 | no | no |
| Licence | AGPL-3.0 (platform). The MCP server and agent SDKs are MIT. Premium capabilities and Lago Cloud are commercial | Proprietary service under the Stripe Services Agreement. The SDKs on GitHub are Apache-2.0 |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| Last release | 2026-10-07 | 2026-09-29 |
| Terms last updated | no document linked | 2026-09-28 |
| Privacy policy last updated | no document linked | 2026-04-28 |
| Customer content may train models |  | yes |
| Terms restrict automated access |  | not found in the text |
| Terms restrict benchmarking |  | not found in the text |
| Terms or service can change without notice |  | yes |
| Arbitration or class-action waiver |  | yes |
| Popularity | 11k stars, 48k npm/wk | 7 stars, 363k npm/wk |

## Verdicts

**Lago.** Lago's open-source edition runs usage metering, plans, wallets and invoicing on the owner's servers at no charge, with an OpenAPI 3.1 file of 217 operations and releases about every two weeks. The free edition has one unscoped API key and no audit logs, and Lago's llms.txt understates what its MCP server can change.

**Metronome.** Metronome's API carries an `Idempotency-Key` on every POST, a public OpenAPI description of 142 operations, and agentic tokens whose writes wait for a person's approval. Prices for the Startup plan are public. Errors return only a `message` string, token scopes are set through support, and the status feed lists 13 incidents since 22 July 2026.

## Before you call either

### Lago

1. Call `<your Lago API origin>/api/v1` with `Authorization: Bearer <key>`. On Lago Cloud the hosts are `api.getlago.com` and `api.eu.getlago.com`
2. Send every usage event with a deterministic `transaction_id` and an explicit `timestamp`, and resend the same payload on retry. On the ClickHouse event store a changed timestamp is billed again
3. Expect 422 `value_already_exist` for a repeated event on the Postgres event store. Treat it as success for a retry
4. Page with `page` and `per_page` and read `meta.next_page` and `meta.total_count`. The default page size is 100 in most cases
5. Treat the free edition's API key as full access. It can void invoices and terminate subscriptions, so keep it out of prompts and ask a person before financial changes
6. Before giving an assistant the MCP server, note that it includes `delete_invoice`, `void_invoice`, `delete_plan` and `create_payment` and sets no read-only annotations

### Metronome

1. Send an `Idempotency-Key` header on every POST and reuse it on retry. A cached error is returned for the same key, so use a new key after fixing the cause
2. Give each usage event a stable `transaction_id`. Metronome ignores repeats for 34 days and accepts at most 100 events per `/v1/ingest` call
3. On 429 read `X-Metronome-Rate-Limit-Type` (`client` or `customer`) and back off. Unlisted endpoints default to 8 requests a second
4. With an agentic token, expect `403 AgenticMutationBlocked` on writes. Post the original method, path and body to `/v1/approval_requests` and show the person the `approval_url`
5. Use a sandbox token for testing. The token alone decides whether a call reaches sandbox or production data

## Questions

### Which is better for AI agents, Lago or Metronome?

Metronome scores 69.7 (B) on agent readiness against Lago's 65.7 (B), and leads in 4 of 7 scored categories. Lago leads on reliability, payments & pricing and maintenance & community.

### Do Lago and Metronome need an API key?

Both need an API key.

### Can an agent call Lago and Metronome without installing anything?

No hosted endpoint is listed for Lago. Metronome has a hosted endpoint at https://api.metronome.com.

### Are Lago and Metronome open source?

Lago is open source (AGPL-3.0 (platform). The MCP server and agent SDKs are MIT. Premium capabilities and Lago Cloud are commercial). No open-source release is listed for Metronome.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/lago-vs-metronome.json, and with the fewest tokens: https://www.anchorterminal.com/compare/lago-vs-metronome.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "lago", "b": "metronome"}`. From a terminal: `anchor compare lago metronome`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/lago.json and https://www.anchorterminal.com/api/v1/tools/metronome.json

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