Merge Accounting API by Merge

# Fix list: Merge Accounting API

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/merge-accounting, the October 2026 research run, assessed 1 October 2026. Grade BB, 70.2 out of 100.

This is everything the published grade says the listing lacks, the biggest possible gain to the total first. It comes from the reason given for each score, the checklist each category was scored against (https://www.anchorterminal.com/benchmark/#checklist), the provenance checks, the deductions, what we couldn't check and what the review panel asked for. A fix counts at the next check, once it's public.

For a coding agent working on Merge Accounting API: work through the items below in the product, its docs and its public pages. Each category gives the reason for its score, with the points each checklist item earned, and the checklist itself, so the gap is the items that earned less than their points. Change the product, not the wording, and keep a note of what you changed and where it's published.

## 1. Payments & pricing, 35 out of 100, up to 8.1 more on the total

Why it scored 35: No x402, MPP or L402 (0). Launch is $650 a month for 10 production linked accounts plus $65 for each one after, a published marginal price per account. Professional and Enterprise are on contract (15). The first 3 production linked accounts are free with no card (20). Browser signup and a Merge Link flow per customer (0).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-payments):

The published rubric, also on the [x402 page](https://www.anchorterminal.com/x402/).

- 40, a machine payment protocol (x402, MPP or L402) on the tool's own endpoints. 10 to 30 when it covers only some endpoints or only goes through a third party, and the note says which.
- 20, per-call or per-unit pricing published without a login. 10 for public plan-only pricing, 0 for "contact sales" or prices behind a login.
- 20, a free tier or trial that doesn't need a card.
- 20, autonomous onboarding, meaning an agent can get access without a person signing up in a browser (keyless use, x402, a programmatic key API).

Payment platforms and agent wallets rarely charge for their own API over a machine protocol, so the first line has steps for them, and the highest one that applies counts. 40 when x402, MPP or L402 runs on all their own endpoints, 30 when it runs on part of their own API, 25 when their merchants can accept one, 20 for running a facilitator, 15 for paying as a buyer, and 0 when the only protocol is their own. Merchant acceptance sits above a facilitator because the platform's own customers can charge agents through it, while a facilitator settles for sellers who wire up the protocol themselves. The counter-argument (a facilitator does more for the protocol as a whole) has a point. Each note says which step applied.

Open-source software you run yourself is scored on its hosted or paid option if it has one. A free, self-hosted package with nothing to buy gets 20, 20 and 20 for the last three lines, and 0 to 40 for the first only if it ships a payment protocol.

## 2. Security & auth, 67 out of 100, up to 5.8 more on the total

Why it scored 67: Production and test API keys plus an X-Account-Token per linked account, so one token reaches one customer. Merge holds the platform OAuth tokens, and the agent never sees them (22). Scopes to limit common models and fields, field-level on Professional and above. No read-only key documented (12). Ledger text from third parties comes back unfiltered with no injection guidance, and the per-account token limits what an injected prompt can reach (5). Request logs kept 3 days on Launch, 30 on Professional and 90 or more on Enterprise (12). SOC 2 Type 2, ISO 27001:2022, a penetration test report and a responsible-disclosure programme on trust.merge.dev. security.txt 404, no bug bounty found (16).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-security):

- 0 to 30, the credential model. 30 for OAuth 2.1 with scopes, or scoped and revocable keys with rotation. 20 for plain revocable API keys. 10 for one all-powerful key. 10 off when a secret can travel in a URL query string as a documented option.
- 0 to 20, read-only or least-privilege modes, and confirmation or approval for destructive actions.
- 0 to 15, prompt-injection posture where the tool returns untrusted content (documented mitigations or guidance). A tool that returns no untrusted content gets 10.
- 0 to 15, audit logs or per-call visibility for the operator.
- 0 to 20, a security programme. security.txt or a disclosure policy, a bug bounty, SOC 2 or ISO 27001, advisories handled in public.

Models are read for retention, whether API data trains models (and whether that's off by default), zero-retention options and certifications. Frameworks for telemetry defaults, approval hooks, guardrails and sandboxing.

## 3. Reliability, 75 out of 100, up to 5 more on the total

Why it scored 75: Status page on Sorry with components for the Unified API, Merge Link, data syncing and Agent Handler (20). QuickBooks Online syncing was out for 17 hours 39 minutes on 1 and 2 September, which the page traces to Intuit's infrastructure, and an ADP relink fault was open on 30 September (HRIS, not accounting). A long outage, but upstream, so we scored it between one major and minor-only (15). 100, 400 or 600 requests a minute per linked account by plan (15). The docs say nothing about 429, Retry-After or retrying writes. The official SDKs retry 429, 408 and 409 with Retry-After and exponential backoff (5). Uptime SLA on Enterprise (10). GA (10).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-reliability):

Hosted APIs, MCP servers, models and platforms.

- 20, a public status page with component history (Statuspage, Instatus, BetterStack or the vendor's own).
- 0 to 30, the incident record for the last 90 days on that page. 30 for a clean record or trivial incidents only, 20 for minor incidents only, 10 for one major outage (an hour or more of a core API down, or errors across the board), 0 for several. 5 when there's no history we could read, and the note says so.
- 15, rate limits documented with numbers.
- 15, documented 429 or overload handling (Retry-After, backoff guidance), and idempotency keys or safe-retry guidance where writes are involved.
- 10, an SLA published for any paid tier.
- 10, the surface agents use is generally available, not beta or preview.

Local packages, SDKs, frameworks and stdio MCP servers.

- 20, installs from an official package with supported runtimes stated.
- 25, a public CI and test suite, passing on the default branch.
- 0 to 25, open crash or regression issues relative to activity (25 for few and handled, 0 for many, old and unanswered).
- 15, semver discipline and breaking changes called out in a changelog.
- 15, version 1.0 or later, or declared stable.

Protocols are read from their reference implementations, the public facilitators or servers, spec stability and test vectors.

## 4. Agent ergonomics, 72 out of 100, up to 4.6 more on the total

Why it scored 72: expand, include_remote_data and remote_fields are opt-in, page_size and modified_after trim reads, no field selection (18). Cursor pagination with created_after, modified_after and type filters on lists (20). Write responses carry warnings and errors from the platform, with logs in debug mode (14). No idempotency keys found for writes, and the SDKs retry 409 by default, so a timed-out POST needs a check before a retry (5). The meta endpoint says which fields a platform needs, and official SDKs cover Python, Node and others (15).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-ergonomics):

- 0 to 25, context cost. For MCP, the number and size of the tool definitions (25 for ten or fewer compact tools, 15 for 11 to 30, 5 for more than 30, plus up to 10 back for toolsets, dynamic loading or read-only subsets). For APIs, whether responses can be sized (field selection, limits, summaries).
- 20, pagination, filtering and output-size controls.
- 20, actionable, documented error responses, codes and messages an agent can recover from.
- 20, idempotency or safe retries, and for MCP the `readOnlyHint` and `destructiveHint` annotations.
- 15, sensible defaults, few required parameters, and official SDKs in at least two languages.

Models are read for tool use, structured output, prompt caching, context length, batch and SDKs. Frameworks for how much code and how many defaults a tool-calling agent with MCP needs.

## 5. Transparency & trust, 70 out of 100, up to 2.6 more on the total

Made of editorial 54, provenance 86.

Why it scored 70: Closed service with published terms naming Merge API Inc. under California law (15). Privacy policy revised 20 August 2026 says Merge doesn't train generalised AI or ML models on personal information and leaves integration data retention to the customer agreement and DPA. Log retention per plan is public, retention of synced data isn't (20). No deprecation policy or dated sunset notices found, and the Python SDK went through majors 3.0 and 4.0 between May and July 2026 (5). Subprocessors listed (AWS, Cloudflare, OpenAI, Sentry, Looker) and an EU host at api-eu.merge.dev, without data locations per subprocessor (14).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-transparency):

- 0 to 30, source availability and licence clarity. 30 for open source under an OSI licence, 15 for closed with clear terms, 0 for unclear terms.
- 0 to 30, data handling and retention statements that agree with each other (privacy policy, DPA, retention periods, subprocessors).
- 0 to 20, a deprecation policy or notices with dates.
- 0 to 20, telemetry disclosed with an opt-out (local software), or subprocessors and data locations disclosed (hosted).

The other half of Transparency and trust is the provenance score, computed from checked facts (below). The category score is the mean of the two.

Provenance checks not met in full (half of this category, computed from checked facts):

- Domain age: merge.dev, registered 2020-02-09 (6 years) (11 of 15)
- security.txt: not found (0 of 10)

## 6. Schema & documentation, 86 out of 100, up to 2.3 more on the total

Why it scored 86: OpenAPI spec for accounting published as JSON at docs.merge.dev/openapi/accounting.json (25). llms.txt with about 70 links, every docs page available as .md (10). Docs explain each common model and point writers to the meta endpoint for per-platform required fields, though not when to avoid a route (15). Typed models with enums such as ACCOUNTS_PAYABLE and ACCOUNTS_RECEIVABLE and typed expand values (13). Write responses document model, warnings, errors and debug logs, but llms.txt lists no errors page (10). Weekly dated changelog and semver SDKs, with the API fixed at /v1 and no deprecation notices (13).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-schema):

APIs and MCP servers.

- 25, a machine-readable contract (a public OpenAPI file or similar; for MCP, typed JSON Schema inputs on every tool).
- 10, llms.txt or Markdown docs served for agents.
- 0 to 20, descriptions that say what a tool is for, when to use it and when not to, read from the tool definitions in the source or the API reference.
- 0 to 15, typed inputs with enums, constraints and required fields, and no free-form JSON blobs.
- 0 to 15, examples and documented error responses.
- 15, versioning and a public changelog.

Models are read from the API reference, the OpenAPI file, llms.txt, the structured-output and tool-use docs and the model cards. Frameworks from docs a model can follow, typed interfaces, examples and the API reference.

## 7. Maintenance & community, 83 out of 100, up to 1.5 more on the total

Why it scored 83: Changelog entry for the Unified API on 25 September and MergePythonClient v4.2.0 on 16 September (30). Weekly changelog entries and three Python SDK tags since 3 July (20). Closed service with a weekly changelog, support@merge.dev and a help centre (12). Current official SDKs (Python 4.2.0, Node 4.0.4), but the official Unified API MCP server, merge-mcp, hasn't changed since 0.1.4 on 30 April 2025 (13). SDK CI and Semgrep scanning (8).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-maintenance):

- 0 to 30, time since the last release, or the last published model or API change for a closed service. 30 within 30 days, 20 within 90, 10 within 180, 0 older.
- 20, at least three releases or dated changelog entries in the last 90 days.
- 0 to 25, responsiveness. Issues and pull requests answered on GitHub (the open issues and how recent the replies are). For closed services, a public changelog and a support or community channel that answers, 0 to 15.
- 15, presence in the official MCP registry under a verified namespace (MCP servers), or current official SDKs (APIs and models).
- 10, package health, current dependencies and CI.

Models are read for deprecation notice periods and model churn rather than release counts.

## What we couldn't check

What we couldn't read counted as absent. Publishing it on a page a plain HTTP fetch can read (not only in a browser) lets the next check count it.

- Whether the Unified API returns Retry-After or rate-limit headers on 429
- How long Merge keeps synced accounting data, which the privacy policy leaves to the customer agreement
- Whether scopes can make a key read-only
- What the pricing page's "sandbox accounts" contain, which we read as Merge-hosted sandboxes with sample data

## Weaknesses

- Launch jumps from free to $650 a month at the fourth linked account
- No documented 429 handling, idempotency keys or safe-retry guidance for writes
- Merge's own MCP server for the Unified API has been idle since 0.1.4 in April 2025
- No deprecation policy, and the Python SDK shipped two major versions between May and July 2026
- Only 3 days of request logs on Launch

## What costs an agent a turn today

The notes we give agents before they call it. Each one is a workaround an agent shouldn't need.

- Call GET /invoices/meta/post for the linked account first. Required fields differ by platform
- Bills and sales invoices are one model. Set type to ACCOUNTS_PAYABLE or ACCOUNTS_RECEIVABLE
- Append .md to any docs URL for the Markdown twin
- Check sync_status before reading a freshly linked account. Common models fill in over the first sync
- Look the record up before retrying a POST that timed out. There's no idempotency key

## What the review panel asked for

- add an errors page
- document 429 and write retries
- read-only API key
- longer logs on Launch

## When it's done

Send what changed and where it's published as a dispute (https://www.anchorterminal.com/builders/#disputes, or `POST https://www.anchorterminal.com/api/v1/contact` with `"kind": "dispute"`). Disputes are answered in public, and the listing is checked again by the same checklist. Paying for an audit or a listing claim changes nothing here.