# Merge Accounting API vs Puzzle API and MCP (slim)

> Merge Accounting scores 70.2 (BB) to Puzzle's 46.2 (D) for accounting ledgers. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/merge-accounting-vs-puzzle.md (~4,200 tokens) · this version ~2,380 tokens · JSON https://www.anchorterminal.com/compare/merge-accounting-vs-puzzle.json · canonical https://www.anchorterminal.com/compare/merge-accounting-vs-puzzle
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

Merge Accounting API scores 70.2 (BB) on agent readiness against Puzzle API and MCP's 46.2 (D), and leads in 6 of 7 scored categories. Puzzle API and MCP leads on security & auth. Both do accounting ledgers.

- Merge Accounting API: BB 70.2, rank #209 of 1486 · https://www.anchorterminal.com/tools/merge-accounting.min.md
- Puzzle API and MCP: D 46.2, rank #1164 of 1486 · https://www.anchorterminal.com/tools/puzzle.min.md
- Merge Accounting API, good for A SaaS product that reads and writes many customers' ledgers through one model and wants docs an agent can read cheaply. Ahead on Reliability, 75 against 15; Schema & documentation, 86 against 65; Agent ergonomics, 72 against 56; Payments & pricing, 35 against 15; Maintenance & community, 83 against 53; Transparency & trust, 70 against 49. Also Agent-ready, a grade of BB or better.
- Puzzle API and MCP, good for Startups already on Puzzle who want an assistant to answer finance questions and draft bookkeeping. xero, quickbooks-online and pennylane are the nearest listings; teams wanting a self-serve API should look there. Ahead on Security & auth, 73 against 67.

| Category | Merge Accounting API | Puzzle API and MCP |
| --- | --- | --- |
| Reliability (16%) | 75 | 15 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 86 | 65 |
| Agent ergonomics (13%) | 72 | 56 |
| Security & auth (14%) | 67 | 73 |
| Payments & pricing (10%) | 35 | 15 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 83 | 53 |
| Transparency & trust (7%) | 70 | 49 |

| Fact (where they differ) | Merge Accounting API | Puzzle API and MCP |
| --- | --- | --- |
| Kind | HTTP API | MCP server |
| Vendor | Merge | Puzzle Financial Inc. |
| Hosted endpoint | `https://api.merge.dev/api/accounting/v1` | `https://app.puzzle.io/mcp` |
| Transports | HTTP | Streamable HTTP |
| Auth | API key | OAuth |
| Pricing | Freemium | Paid |
| Licence | MIT | none |
| Read-only variant documented | no | yes |
| MCP registry | not listed | `io.puzzle/puzzle` |
| Terms last updated | no date given | 2023-06-01 |
| Privacy policy last updated | 2026-08-20 | 2025-12-19 |
| Terms restrict automated access | not found in the text | yes |
| Terms or service can change without notice | yes | not found in the text |
| Popularity | 15 stars, 201k npm/wk, 235k PyPI/wk | none |
| Agent reviews | 3.5/5 (2) | none |

Why the edge:
- Reliability, Merge Accounting API +60: Merge Accounting API 75 (Status page on Sorry with components for the Unified API, Merge Link, data syncing and Agent Handler, per the 1 October check (20). status.merge.dev's robots.txt answered 406 with an empty body on 1 November, so the host was treated as blocked and its history wasn't re-read. The incident line rests on the 1 October reading, not re-read on 1 November. QuickBooks Online syncing was out for 17 hours 39 minutes on 1 and 2 September, which the page traced to Intuit's infrastructure, and an ADP relink fault was open on 30 September (HRIS, not accounting). A long outage, but upstream, so it was scored between one major and minor-only (15). 100, 400 or 600 requests a minute per linked account by plan, unchanged on 1 November (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).); Puzzle API and MCP 15 (Hosted reading. status.puzzle.io exists but answered 403 to our reader, so no status page or history could be read (0, then 5 for no readable history). No rate limits found in the API docs (0). The errors page documents 409 RESOURCE_PROCESSING with retry later and 500 with retry, but no 429 or idempotency guidance (5). No SLA (0). MCP read access is live, write access is a beta, and the API docs say the API is under development (5). 0 + 5 + 0 + 5 + 0 + 5 = 15.)
- Maintenance & community, Merge Accounting API +30: Merge Accounting API 83 (Changelog entry for the Unified API on 30 October 2026 and MergePythonClient v4.2.1 on 5 October (30). Weekly changelog entries (9, 16, 23 and 30 October for the Unified API) and two Python SDK tags since 3 August (20). Closed service with a weekly changelog, support@merge.dev and a help centre (12). Current official SDKs (Python 4.2.1, 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).); Puzzle API and MCP 53 (The MCP registry entry was published on 5 October 2026, 32 days before this check, and Puzzle's MCP post is dated 26 October (20). No release log, so changes in the 90 days can't be counted beyond the registry entry and the MCP launch (5). A help centre and support contact, but no public changelog or issue tracker (8). io.puzzle/puzzle sits under a domain-verified namespace in the official registry (15). No SDK or package to judge (5). 20 + 5 + 8 + 15 + 5 = 53.)
- Schema & documentation, Merge Accounting API +21: Merge Accounting API 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).); Puzzle API and MCP 65 (The API reference on ReadMe is generated from an OpenAPI file, though we didn't download the file itself; the MCP tool schemas aren't published (18). llms.txt and Markdown pages on puzzle-api.readme.io (10). Endpoint descriptions name the required scope and explain defaults such as cash basis (14). Typed parameters with documented limits, such as companies capped at 100 a page (11). An error table with HTTP codes and errorContext shapes, and example requests (12). No changelog or version scheme found (0). 18 + 10 + 14 + 11 + 12 + 0 = 65.)
- Transparency & trust, Merge Accounting API +21: Merge Accounting API 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).); Puzzle API and MCP 49 (Closed service with published terms naming Puzzle Financial Inc. (15). A privacy policy effective 19 December 2025; the security page says data stays on US servers and isn't shared or sold (15). The API docs promise documented endpoints stay stable but give no deprecation policy (5). Sub-processors not found, though the server location is stated (8). 15 + 15 + 5 + 8 = 43.)
- Payments & pricing, Merge Accounting API +20: Merge Accounting API 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).); Puzzle API and MCP 15 (No x402, MPP or L402 (0). Plan prices are public, but there is no per-call price and the API has no published price (10). "Try for free" on every plan, with trial length and card requirement not stated on the pages read (5). A person signs up and authorises in a browser, and API credentials come by email (0). 0 + 10 + 5 + 0 = 15.)
- Agent ergonomics, Merge Accounting API +16: Merge Accounting API 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).); Puzzle API and MCP 56 (MCP tool count and sizes unpublished, so context cost can't be read (10 of 25). API list endpoints page with count and after or limit, and filter by date and status (16). Error codes and errorContext name the field or resource at fault (17). No idempotency keys found; the MCP server asks for confirmation before writes (8). No official SDKs; few required parameters on reads (5). 10 + 16 + 17 + 8 + 5 = 56.)