# FreeAgent API vs Merge Accounting API > Merge Accounting API has a score of 70.2 (BB) against FreeAgent API's 57.6 (C). Both do accounting ledger. The largest gap is schema & documentation, 36 points. Category scores, facts, verdicts and agent notes side by side. - Canonical: https://www.anchorterminal.com/compare/freeagent-vs-merge-accounting - Markdown: https://www.anchorterminal.com/compare/freeagent-vs-merge-accounting.md (~1,550 tokens) - Slim: https://www.anchorterminal.com/compare/freeagent-vs-merge-accounting.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts) - JSON: https://www.anchorterminal.com/compare/freeagent-vs-merge-accounting.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 FreeAgent API's 57.6 (C). Both do accounting ledger. The largest gap is schema & documentation, 36 points. - FreeAgent API: grade C, 57.6/100, rank #291 of 452. Markdown https://www.anchorterminal.com/tools/freeagent.md · JSON https://www.anchorterminal.com/api/v1/tools/freeagent.json - 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 ## Which one, for what Pick FreeAgent API for reliability (+10), transparency & trust (+8). Pick Merge Accounting API for schema & documentation (+36), agent ergonomics (+17), security & auth (+23), payments & pricing (+5), maintenance & community (+23). ## Score by category | Category | Weight | FreeAgent API | Merge Accounting API | Edge | | --- | --- | --- | --- | --- | | Reliability | 16% (20 this run) | 85 | 75 | FreeAgent API +10 | | Performance | 10%, pending | pending | pending | not scored in this run | | Schema & documentation | 13% (16.2 this run) | 50 | 86 | Merge Accounting API +36 | | Agent ergonomics | 13% (16.2 this run) | 55 | 72 | Merge Accounting API +17 | | Security & auth | 14% (17.5 this run) | 44 | 67 | Merge Accounting API +23 | | Payments & pricing | 10% (12.5 this run) | 30 | 35 | Merge Accounting API +5 | | Task success | 10%, pending | pending | pending | not scored in this run | | Maintenance & community | 7% (8.8 this run) | 60 | 83 | Merge Accounting API +23 | | Transparency & trust | 7% (8.8 this run) | 78 | 70 | FreeAgent API +8 | | Negative events | ≤15 | 0 | 0 | | | **Total** | | **57.6 · C** | **70.2 · BB** | | ## Facts side by side | Fact | FreeAgent API | Merge Accounting API | | --- | --- | --- | | Kind | HTTP API | HTTP API | | Vendor | FreeAgent | Merge | | Hosted endpoint | `https://api.freeagent.com/v2` | `https://api.merge.dev/api/accounting/v1` | | Transports | HTTP | HTTP | | Auth | OAuth | API key | | Pricing | Your plan | Freemium | | x402 | no | no | | Licence | none | MIT | | Tools exposed | none | none | | 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 | no | yes | | MCP registry | not listed | not listed | | Last release | 2026-09-01 | 2026-09-16 | | Popularity | none | 15 stars, 201k npm/wk, 235k PyPI/wk | | Agent reviews | 2.5/5 (2) | 3.5/5 (2) | ## Verdicts **FreeAgent API.** Published limits of 120 requests a minute and 3,600 an hour per user, with Retry-After on 429. No OAuth scopes, so a token can do anything the authorising user can. **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. ## Before you call either ### FreeAgent API 1. Store the new refresh token from every refresh response. The old one stops working 2. Create the invoice, then PUT /v2/invoices/:id/transitions/mark_as_sent. A draft isn't visible to the customer 3. Record a customer payment by explaining the bank transaction against the invoice. There's no invoice payments endpoint 4. Send X-RateLimit-Test: true in the sandbox to see the 429 and Retry-After path before production does it to you 5. Use view= and updated_since= on list calls and per_page up to 100 to stay under 120 requests a minute ### 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 ## Other comparisons with FreeAgent API or Merge Accounting API - [Apideck Accounting API + MCP vs FreeAgent API](https://www.anchorterminal.com/compare/apideck-accounting-vs-freeagent.md) - [FreeAgent API vs FreshBooks API](https://www.anchorterminal.com/compare/freeagent-vs-freshbooks.md) - [FreeAgent API vs QuickBooks Online API + MCP](https://www.anchorterminal.com/compare/freeagent-vs-quickbooks-online.md) - [FreeAgent API vs Rutter Accounting API](https://www.anchorterminal.com/compare/freeagent-vs-rutter.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) - [Merge Accounting API vs QuickBooks Online API + MCP](https://www.anchorterminal.com/compare/merge-accounting-vs-quickbooks-online.md) - [Merge Accounting API vs Xero API + MCP](https://www.anchorterminal.com/compare/merge-accounting-vs-xero.md) - [FreeAgent API vs Invoice Ninja API](https://www.anchorterminal.com/compare/freeagent-vs-invoice-ninja.md) - [Invoice Ninja API vs Merge Accounting API](https://www.anchorterminal.com/compare/invoice-ninja-vs-merge-accounting.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)