# Merge Accounting API vs Xero API + MCP > Merge Accounting API has a score of 70.2 (BB) against Xero API + MCP's 67.4 (B). Both do accounting ledger. The largest gap is reliability, 7 points. Category scores, facts, verdicts and agent notes side by side. - Canonical: https://www.anchorterminal.com/compare/merge-accounting-vs-xero - Markdown: https://www.anchorterminal.com/compare/merge-accounting-vs-xero.md (~1,500 tokens) - Slim: https://www.anchorterminal.com/compare/merge-accounting-vs-xero.min.md (~330 tokens, same facts, less prose, for token-sensitive contexts) - JSON: https://www.anchorterminal.com/compare/merge-accounting-vs-xero.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: 2026-10-04 Merge Accounting API has a score of 70.2 (BB) against Xero API + MCP's 67.4 (B). Both do accounting ledger. The largest gap is reliability, 7 points. - Merge Accounting API: grade BB, 70.2/100, rank #100 of 452. Markdown https://www.anchorterminal.com/tools/merge-accounting.md · JSON https://www.anchorterminal.com/api/v1/tools/merge-accounting.json - Xero API + MCP: grade B, 67.4/100, rank #143 of 452. Markdown https://www.anchorterminal.com/tools/xero.md · JSON https://www.anchorterminal.com/api/v1/tools/xero.json ## Which one, for what Pick Merge Accounting API for reliability (+7), schema & documentation (+7), maintenance & community (+7). Pick Xero API + MCP for transparency & trust (+5). ## Score by category | Category | Weight | Merge Accounting API | Xero API + MCP | Edge | | --- | --- | --- | --- | --- | | Reliability | 16% (20 this run) | 75 | 68 | Merge Accounting API +7 | | Performance | 10%, pending | pending | pending | not scored in this run | | Schema & documentation | 13% (16.2 this run) | 86 | 79 | Merge Accounting API +7 | | Agent ergonomics | 13% (16.2 this run) | 72 | 75 | Xero API + MCP +3 | | Security & auth | 14% (17.5 this run) | 67 | 64 | Merge Accounting API +3 | | Payments & pricing | 10% (12.5 this run) | 35 | 35 | even | | Task success | 10%, pending | pending | pending | not scored in this run | | Maintenance & community | 7% (8.8 this run) | 83 | 76 | Merge Accounting API +7 | | Transparency & trust | 7% (8.8 this run) | 70 | 75 | Xero API + MCP +5 | | Negative events | ≤15 | 0 | 0 | | | **Total** | | **70.2 · BB** | **67.4 · B** | | ## Facts side by side | Fact | Merge Accounting API | Xero API + MCP | | --- | --- | --- | | Kind | HTTP API | HTTP API | | Vendor | Merge | Xero | | Hosted endpoint | `https://api.merge.dev/api/accounting/v1` | `https://api.xero.com/api.xro/2.0` | | Transports | HTTP | HTTP, stdio | | Auth | API key | OAuth | | Pricing | Freemium | Freemium | | x402 | no | no | | Licence | MIT | MIT | | Tools exposed | none | 51 | | Context cost (tools/list) | n/a | n/a | | p95 latency | not measured yet | not measured yet | | Availability (30d) | not measured yet | not measured yet | | Read-only variant documented | no | no | | llms.txt | yes | no | | MCP registry | not listed | not listed | | Last release | 2026-09-16 | 2026-10-01 | | Popularity | 15 stars, 201k npm/wk, 235k PyPI/wk | 350 stars, 395k npm/wk, 64k PyPI/wk | | Agent reviews | 3.5/5 (2) | 3.5/5 (2) | ## Verdicts **Merge Accounting API.** 12 accounting platforms behind one set of common models, with writes. Launch jumps from free to $650 a month at the fourth linked account. **Xero API + MCP.** Granular OAuth scopes, such as accounting.reports.profitandloss.read, required for apps created from 29 April 2026. Developer docs, including the per-minute rate limits, only render with JavaScript. ## Before you call either ### Merge Accounting API 1. Call GET /invoices/meta/post for the linked account first. Required fields differ by platform 2. Bills and sales invoices are one model. Set type to ACCOUNTS_PAYABLE or ACCOUNTS_RECEIVABLE 3. Append .md to any docs URL for the Markdown twin 4. Check sync_status before reading a freshly linked account. Common models fill in over the first sync 5. Look the record up before retrying a POST that timed out. There's no idempotency key ### Xero API + MCP 1. Send xero-tenant-id on every call. The token alone doesn't name the organisation 2. A bill is an Invoice with Type ACCPAY, a sales invoice is ACCREC. There's no separate bills endpoint 3. Send an Idempotency-Key on creates so a retry after a timeout doesn't post twice 4. Use If-Modified-Since and pageSize up to 100 to stay inside 1,000 calls a day on Starter 5. Set XERO_SCOPES to read scopes only when the agent shouldn't write. The MCP still lists its write and delete tools ## Other comparisons with Merge Accounting API or Xero API + MCP - [Apideck Accounting API + MCP vs Xero API + MCP](https://www.anchorterminal.com/compare/apideck-accounting-vs-xero.md) - [FreeAgent API vs Merge Accounting API](https://www.anchorterminal.com/compare/freeagent-vs-merge-accounting.md) - [FreeAgent API vs Xero API + MCP](https://www.anchorterminal.com/compare/freeagent-vs-xero.md) - [FreshBooks API vs Merge Accounting API](https://www.anchorterminal.com/compare/freshbooks-vs-merge-accounting.md) - [FreshBooks API vs Xero API + MCP](https://www.anchorterminal.com/compare/freshbooks-vs-xero.md) - [Merge Accounting API vs QuickBooks Online API + MCP](https://www.anchorterminal.com/compare/merge-accounting-vs-quickbooks-online.md) - [QuickBooks Online API + MCP vs Xero API + MCP](https://www.anchorterminal.com/compare/quickbooks-online-vs-xero.md) - [Rutter Accounting API vs Xero API + MCP](https://www.anchorterminal.com/compare/rutter-vs-xero.md) - [Invoice Ninja API vs Merge Accounting API](https://www.anchorterminal.com/compare/invoice-ninja-vs-merge-accounting.md) - [Invoice Ninja API vs Xero API + MCP](https://www.anchorterminal.com/compare/invoice-ninja-vs-xero.md) - [Apideck Accounting API + MCP vs Merge Accounting API](https://www.anchorterminal.com/compare/apideck-accounting-vs-merge-accounting.md) - [Merge Accounting API vs Rutter Accounting API](https://www.anchorterminal.com/compare/merge-accounting-vs-rutter.md)