# Fastmail API (JMAP) vs Outlook Mail (Microsoft Graph) (slim)

> Outlook Mail (Microsoft Graph) scores 66.3 (B) on agent readiness against Fastmail API (JMAP)'s 54.1 (C), and leads in every scored category. Both do mailbox read. Category scores, facts, verdicts and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph.md (~2,300 tokens) · this version ~730 tokens · JSON https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph.json · canonical https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

Outlook Mail (Microsoft Graph) scores 66.3 (B) on agent readiness against Fastmail API (JMAP)'s 54.1 (C), and leads in every scored category. Both do mailbox read.

- Fastmail API (JMAP): C 54.1, rank #620 of 842 · https://www.anchorterminal.com/tools/fastmail.min.md
- Outlook Mail (Microsoft Graph): B 66.3, rank #272 of 842 · https://www.anchorterminal.com/tools/outlook-mail-graph.min.md
- Fastmail API (JMAP), good for An agent working in its owner's own Fastmail mailbox, where JMAP gives batched reads, structured search and state-based sync on an open standard, and MCP gives a ready connection with read, write and send levels. Also No incidents deducted, where Outlook Mail (Microsoft Graph) loses 4 points for them.
- Outlook Mail (Microsoft Graph), good for Agents working in Microsoft 365 or Outlook.com mailboxes that need scoped reading, drafting, sending and incremental sync. Ahead on Reliability, 60 against 54; Schema & documentation, 93 against 52; Agent ergonomics, 81 against 73; Security & auth, 71 against 60; Payments & pricing, 35 against 30; Maintenance & community, 76 against 26. Also A hosted endpoint, with nothing to install.

| Category | Fastmail API (JMAP) | Outlook Mail (Microsoft Graph) |
| --- | --- | --- |
| Reliability (16%) | 54 | 60 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 52 | 93 |
| Agent ergonomics (13%) | 73 | 81 |
| Security & auth (14%) | 60 | 71 |
| Payments & pricing (10%) | 30 | 35 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 26 | 76 |
| Transparency & trust (7%) | 74 | 75 |

| Fact (where they differ) | Fastmail API (JMAP) | Outlook Mail (Microsoft Graph) |
| --- | --- | --- |
| Vendor | Fastmail Pty Ltd | Microsoft |
| Hosted endpoint | no (local only) | `https://graph.microsoft.com/v1.0` |
| Auth | OAuth or key | OAuth |
| Pricing | Paid | Your plan |
| Licence | Proprietary service under Fastmail's API Terms of Service and API Developer Policy. JMAP is an open IETF standard, and the sample code on GitHub is MIT | MIT (SDKs) |
| Tools exposed | none | 10 |
| Read-only variant documented | yes | no |
| Last release | 2026-04-22 | 2026-10-06 |
| Terms last updated | no date given | 2025-10-01 |
| Privacy policy last updated | no date given | 2026-09-01 |
| Customer content may train models | not found in the text | yes |
| Terms restrict automated access | not found in the text | yes |
| Terms or service can change without notice | not found in the text | yes |
| Popularity | 123 stars | 835 stars, 2.9M npm/wk, 1.6M PyPI/wk |