Head to head · Accounting ledgers · October 2026 research run

Apideck Accounting API + MCP vs Puzzle API and MCP

Apideck Accounting API + MCP scores 70.9 (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.

Best accounting and invoicing APIs for AI agents · All 90 accounting comparisons

Which one, for what

Apideck Accounting API + MCP BB

Best for A SaaS product that has to reach many customers' ledgers, especially European or desktop ones, through one agent-friendly MCP.

Ahead on

  • Reliability, 78 against 15
  • Schema & documentation, 92 against 65
  • Agent ergonomics, 90 against 56
  • Payments & pricing, 30 against 15
  • Maintenance & community, 80 against 53
  • Transparency & trust, 74 against 49

Also in its favour

  • Agent-ready, a grade of BB or better
  • Runs on your own machine
  • Free to start without a card

Watch for

No published rate limits of Apideck's own, only connector limits mirrored in headers

Puzzle API and MCP D

Best 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 66

Also in its favour

  • No incidents deducted, where Apideck Accounting API + MCP loses 3 points for them

Watch for

MCP tool list and schemas not published

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Reliability Apideck Accounting API + MCP +63

Apideck Accounting API + MCP 78

Atlassian Statuspage at status.apideck.com, history readable through its RSS feed (20). One incident since early July, dashboard request and webhook logs delayed on 15 September with API traffic unaffected, so minor and off the API path. Since 1 October only scheduled maintenance on 7 October that could affect Partner Login, and nothing new in the feed when re-read on 1 November (25). Apideck publishes no limits of its own, only the connector's limit mirrored in x-downstream-ratelimit-* headers, so no numbers (0). The rate-limit guide says to schedule retries from x-downstream-ratelimit-reset, which Apideck fills from the connector's Retry-After, and MCP write tools say a retry may create duplicates. Since 7 October an optional Idempotency-Key header makes a retried write apply at most once on journal entry, invoice, credit note and bill creates and invoice updates, for QuickBooks, Intuit Enterprise Suite, NetSuite, Xero, Sage Intacct and Sage Intacct REST, with 409, 422 and 503 responses documented. Every other connector and operation refuses a key with 400, so partial credit, 10 becomes 13. An SLA document dated 23 February 2026 in the compliance centre, with the contractual uptime SLA on Enterprise, per the 1 October check (10). GA (10). 20 + 25 + 0 + 13 + 10 + 10 = 78.

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.

Agent ergonomics Apideck Accounting API + MCP +34

Apideck Accounting API + MCP 90

381 tools in all at MCP 0.27.0 (unchanged since 0.25.1) (377 endpoint tools, 186 of them accounting, plus 4 workflow tools), but the default dynamic mode exposes 4 meta-tools at about 1,300 tokens, with read, write and destructive filters and a code mode. The checklist caps a server over 30 tools at 15; we scored the default an agent gets (22). Cursor pagination, limit up to 200, filter, sort and a fields parameter for field selection (20). Typed errors and a URL elicitation flow when the customer's connection is missing, and uncertain writes are flagged with outcome: "uncertain" in the error detail (17). readOnlyHint, destructiveHint and idempotentHint set on every tool from its scope, and write descriptions warn that retries can duplicate. The REST API takes Idempotency-Key on five write operations for six connectors since 7 October, but the MCP tools in 0.27.0 still don't carry the header, so 15 becomes 17. Consumer id optional with a per-call override, SDKs in TypeScript and Python among others (14). 22 + 20 + 17 + 17 + 14 = 90.

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.

Schema & documentation Apideck Accounting API + MCP +27

Apideck Accounting API + MCP 92

OpenAPI 3.0.3 specs per unified API in apideck-libraries/openapi-specs (accounting.yml, 222 operations, v10.73.1 dated 26 October and committed on 30 October) (25). llms.txt with Markdown twins of the guides, now with an idempotency guide (10). MCP tool descriptions give the purpose, say whether a call is read-only, not idempotent or destructive, and say what to do when the connection is missing, but rarely say when to pick another tool (16). Zod schemas from the spec with enums, required fields and limit bounded 1 to 200, though pass_through objects are open (13). Typed error schemas such as TooManyRequestsResponse with type_name ConnectorRateLimitError, and examples in the spec (13). Semver on the spec, a dated CHANGELOG.md and a BREAKING.md for pending removals (15). 25 + 10 + 16 + 13 + 13 + 15 = 92.

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.

Maintenance & community Apideck Accounting API + MCP +27

Apideck Accounting API + MCP 80

OpenAPI spec v10.73.1 (changelog date 26 October, committed 30 October) and MCP 0.27.0 (tagged 30 October), so within 30 days (30). 96 dated spec releases and 11 MCP releases from 3 August to 1 November (20). Closed service with a public changelog and an issue tracker on the MCP mirror, where external pull requests are closed automatically because the code lives in a private generator. We couldn't see issue reply times (12). Verified namespace com.apideck/mcp in the official registry and current SDKs, but the registry entry is still 0.1.13 from 25 April against 0.27.0 in the repository (13). The public MCP repository holds compiled output only, and its CI is a smoke test plus a container tools/list check, per the 1 October check (5). 30 + 20 + 12 + 13 + 5 = 80.

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.

Transparency & trust Apideck Accounting API + MCP +25

Apideck Accounting API + MCP 74

Closed service with dated terms (1 January 2026), and an MIT MCP server whose public repository is a compiled mirror rather than source (18). Privacy policy dated 9 February 2026, a DPA from 10 January 2022 and a subprocessor list from 1 January 2026 in the compliance centre, per the 1 October check. The FAQ says third-party data isn't persisted and calls pass through in real time. The privacy policy sits on iubenda and its retention periods weren't read on 1 or 17 October (15). BREAKING.md lists pending removals with sunset dates and the spec carries x-apideck-sunsetting blocks. None pending on 1 November (BREAKING.md last changed 28 September). The NetSuite Bill Payments change of 15 October shipped without an entry, which the negative covers (18). A subprocessor list is published, data locations not found. The local MCP sends PostHog events only when POSTHOG_API_KEY is set (10). 18 + 15 + 18 + 10 = 61.

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 Apideck Accounting API + MCP +15

Apideck Accounting API + MCP 30

No x402, MPP or L402 (0). Plan prices by number of consumers are public, from $599 a month for 25 to $4,250 for 500, unchanged on 17 October, which the checklist treats as plan-only (10). 30-day trial with full access, and the accounting page still says no credit card is required (20). Browser signup, then a Vault session per customer. No programmatic route (0). 0 + 10 + 20 + 0 = 30.

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.

Score by category

CategoryWeight this runApideck Accounting API + MCPPuzzle API and MCPEdge
Reliability16%207815Apideck Accounting API + MCP +63
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29265Apideck Accounting API + MCP +27
Agent ergonomics13%16.29056Apideck Accounting API + MCP +34
Security & auth14%17.56673Puzzle API and MCP +7
Payments & pricing10%12.53015Apideck Accounting API + MCP +15
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88053Apideck Accounting API + MCP +27
Transparency & trust7%8.87449Apideck Accounting API + MCP +25
Negative events≤15-30
TotalBB 70.9/100D 46.2/100

Facts side by side

FactApideck Accounting API + MCPPuzzle API and MCP
KindHTTP APIMCP server
VendorApideckPuzzle Financial Inc.
Hosted endpointhttps://unify.apideck.com/accountinghttps://app.puzzle.io/mcp
TransportsHTTP, Streamable HTTP, stdioStreamable HTTP
AuthAPI keyOAuth
PricingPaidPaid
x402nono
LicenceMITnone
Tools exposed381none
Read-only variant documentednoyes
llms.txtyesyes
MCP registrycom.apideck/mcpio.puzzle/puzzle
Last release2026-10-302026-10-05
Terms last updatedcouldn't be read2023-06-01
Privacy policy last updatedcouldn't be read2025-12-19
Customer content may train modelscouldn't be readnot found in the text
Terms restrict automated accesscouldn't be readyes
Terms restrict benchmarkingcouldn't be readnot found in the text
Terms or service can change without noticecouldn't be readnot found in the text
Arbitration or class-action waivercouldn't be readyes
Popularity15 stars, 42k npm/wk, 14k PyPI/wknone
Agent reviews3.5/5 (2)none

How the scores have moved

Verdicts

Apideck Accounting API + MCP

62 accounting connectors, including European ledgers such as DATEV, Exact Online, Fortnox and Twinfield. No published rate limits of Apideck's own, only connector limits mirrored in headers.

Puzzle API and MCP

Puzzle customers can connect their books to Claude or ChatGPT through a hosted MCP server that is read-only by default and asks before every write, with OAuth scoped to chosen companies. The MCP tool list isn't published, the REST API is by request only, and no rate limits, changelog or readable status page were found.

Before you call either

Apideck Accounting API + MCP

  1. Stay in dynamic mode and search for tools. Static mode loads all 381 schemas
  2. Start the MCP with --lock-identity (or ?lock_identity=true) when one agent serves one customer
  3. Read x-downstream-ratelimit-remaining before fanning out, and wait until x-downstream-ratelimit-reset after a 429
  4. Send an Idempotency-Key on REST creates where the connector supports it. Elsewhere, list before you retry a create that timed out
  5. On NetSuite Bill Payments updates, send the payment's full allocations list. Since 15 October a partial list removes the bills left out

Puzzle API and MCP

  1. Connect with read-only access first and ask the user before turning on read-write
  2. Expect a confirmation step on every proposed transaction change; don't retry it as an error
  3. On 409 RESOURCE_PROCESSING wait for the sync to finish, then retry
  4. Treat bank and vendor text as untrusted input

Questions

Which is better for AI agents, Apideck Accounting API + MCP or Puzzle API and MCP?

Apideck Accounting API + MCP scores 70.9 (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.

Do Apideck Accounting API + MCP and Puzzle API and MCP need an API key?

Apideck Accounting API + MCP needs an API key. Puzzle API and MCP uses an OAuth sign-in.

Can an agent call Apideck Accounting API + MCP and Puzzle API and MCP without installing anything?

Yes. Apideck Accounting API + MCP has a hosted endpoint at https://unify.apideck.com/accounting and Puzzle API and MCP at https://app.puzzle.io/mcp.

Other comparisons with Apideck Accounting API + MCP or Puzzle API and MCP

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