{ "data": { "a": { "slug": "fastmail", "name": "Fastmail API (JMAP)", "vendor": "Fastmail Pty Ltd", "vendorUrl": "https://www.fastmail.com", "kind": "http-api", "category": "mailbox-access", "summary": "Fastmail is a paid email, calendar and contacts host from Fastmail Pty Ltd in Melbourne. Agents reach a customer's mailbox through JMAP at api.fastmail.com, the open IETF protocol, or through the company's own MCP server.", "url": "https://www.anchorterminal.com/tools/fastmail", "markdownUrl": "https://www.anchorterminal.com/tools/fastmail.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/fastmail.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/fastmail.json", "repo": "https://github.com/fastmail/JMAP-Samples", "license": "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", "transports": [ "http" ], "packages": [], "auth": "mixed", "authNotes": "Access is self-serve for the account owner. An API token is made in Settings, Privacy \u0026 Security, Manage API tokens, as type JMAP or MCP, with scopes for read-only access, Email, Email submission, Contacts and Masked Email, and is sent as `Authorization: Bearer`. Tokens are not available on Basic plans. An app distributed to other users needs OAuth 2.0 (authorisation code grant, PKCE S256, rotating refresh tokens), and the developer page says clients are registered by hand through the partnerships team. The MCP server takes OAuth or an MCP-type token, and the authorisation server metadata lists a registration endpoint.", "pricing": "paid", "pricingNotes": "API access is part of a mailbox plan, with no per-call charge. Individual is $6 a month or $60 a year, Business Standard $6 a user a month and Professional $10. Basic, at $4, has no API tokens. A trial of up to 30 days needs no card, so an agent's owner can start without a contract, with sending capped at 120 messages a day (https://www.fastmail.com/pricing/us/, checked 2026-10-08).", "priceSummary": "$6 / mo", "where": "local", "x402": { "level": "no", "evidence": "No x402, MPP or L402 on the developer page, the pricing page or the 401 responses from api.fastmail.com (checked 2026-10-08).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": 123, "npmWeekly": null, "pypiWeekly": null, "asOf": "2026-10-08" }, "docsUrl": "https://www.fastmail.com/dev/", "capabilities": [ "mailbox.read", "mailbox.search", "mailbox.send", "mailbox.drafts", "mailbox.sync" ], "tags": [ "hosted", "paid", "trial", "jmap", "open-standard", "oauth", "api-key", "mcp", "email", "contacts", "masked-email", "status-page", "bug-bounty", "eu-data-residency" ], "lastRelease": "2026-04-22", "graded": true, "anchor": { "graded": true, "score": 54.1, "grade": "C", "agentReady": false, "rank": 620, "ranked": true, "rankOf": 842, "categoryRank": 6, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 73, "maintenance": 26, "payments": 30, "reliability": 54, "schema": 52, "security": 60, "transparency": 74 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-08" }, "negative": 0, "verdict": "A mailbox API built on the open JMAP standard, with read-only tokens, six OAuth scopes and an MCP server that separates read, write and send access. Fastmail publishes no OpenAPI file, SDK, API changelog, request rate limit or SLA, and its customer terms forbid programmatically generated email to addresses outside the account.", "bestFor": "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.", "strengths": [ "JMAP is an IETF standard (RFC 8620, 8621 and 9610), so requests, types and errors are specified in public and not tied to one vendor", "API tokens can be read-only or limited to mail, sending, contacts or Masked Email, and are revocable in settings", "OAuth 2.0 requires PKCE with S256, rotates refresh tokens on every use and revokes the grant if an old one is replayed", "The MCP server at `https://api.fastmail.com/mcp`, launched 22 April 2026, has separate read, write and send levels chosen on the consent screen", "`properties`, `limit`, `bodyProperties` and `maxBodyValueBytes` size responses, and several calls batch into one request with back-references", "30-day trial with no card, a privacy policy with stated retention periods and a published list of 36 subprocessors" ], "weaknesses": [ "The customer terms forbid programmatically generated email to addresses outside the account, and say the service is not for machine-to-machine workflows", "No OpenAPI file, llms.txt, official SDK or API changelog. The developer page points to the RFCs and four sample scripts", "No request rate limit, Retry-After guidance or SLA was found, and the API terms allow backwards-incompatible changes with notice only promised as an attempt", "Three partial outages between 25 August and 7 October 2026 blocked access for some users for 8 hours 16 minutes, 1 hour 8 minutes and 5 hours 23 minutes", "API tokens are not available on Basic plans, and the developer page says OAuth clients are registered by hand through the partnerships team", "No idempotency key on `EmailSubmission/set`, no confirmation step for delete or send, and no per-call access log", "Fastmail says it has not pursued SOC certification, and no ISO 27001 certificate was found" ], "agentNotes": [ "Fetch `https://api.fastmail.com/jmap/session` with `Authorization: Bearer \u003ctoken\u003e` first. It returns the API URL, account IDs and the request limits to stay under", "Ask the owner for a read-only token unless the task writes. Sending needs both the Email and Email submission scopes", "Request only the `properties` you need. Body text is not returned unless `fetchTextBodyValues` is set, and `maxBodyValueBytes` caps it", "Sync with `Email/changes` from a stored state. On `cannotCalculateChanges`, fetch again from scratch", "Do not send generated mail to outside recipients without the owner's review. The customer terms forbid it, and trial accounts stop at 120 messages a day" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 54.1 } ], "editorialScores": { "ergonomics": 73, "maintenance": 26, "payments": 30, "reliability": 54, "schema": 52, "security": 60, "transparency": 62 }, "provenanceScore": 86 }, "connect": { "http": "curl https://api.fastmail.com/jmap/session \\\n -H \"Authorization: Bearer YOUR_API_TOKEN\"" }, "letme": { "capability": "https://letme.dev/mailbox.read", "tool": "https://letme.dev/fastmail" }, "area": "communication", "unitPrices": [ { "item": "Individual plan, billed monthly", "unit": "month", "usd": 6, "note": "one mailbox, API tokens included, 30-day trial without a card" }, { "item": "Individual plan, $60 billed yearly", "unit": "month", "usd": 5, "note": "one mailbox, API tokens included" }, { "item": "Business Standard, billed monthly", "unit": "seat-month", "usd": 6, "note": "per user, API tokens included. Basic at $4 has none" } ], "provenance": { "legalEntity": "Fastmail Pty Ltd, ACN 142 646 580, PO Box 234, Collins Street West, VIC 8007, Australia", "domain": "fastmail.com", "domainRegistered": "1994-12-09", "endpointOnVendorDomain": true, "terms": "https://www.fastmail.com/policies/api-terms-of-service/", "privacy": "https://www.fastmail.com/policies/privacy/", "statusPage": "https://fastmailstatus.com/", "changelog": "", "securityTxt": "valid", "checked": "2026-10-08", "notes": [ "The privacy policy names Fastmail Pty Ltd with ABN 31 142 646 580, and the terms of service give ACN 142 646 580, both at PO Box 234, Collins Street West, VIC 8007.", "RDAP for fastmail.com shows registration on 9 December 1994 and expiry on 8 December 2034.", "www.fastmail.com/.well-known/security.txt expires on 24 June 2027 and points to the bug bounty page for contact and policy.", "The API Terms of Service and the API Developer Policy together form the contract for API use, governed by the law of Victoria, Australia. The customer Terms of Service, last changed 10 October 2025 per its version list, govern the account the API reaches.", "The privacy policy lists versions back to 25 May 2020, the latest dated 2 July 2026.", "JMAP, OAuth and MCP all answer on api.fastmail.com. The status page is on fastmailstatus.com, hosted by Instatus.", "No API changelog was found." ], "score": 86 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/fastmail.json", "live": { "slug": "fastmail", "vendorStatus": { "page": "https://fastmailstatus.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-09T07:57:54.65130148Z" }, "updatedAt": "2026-10-09T07:57:54.65130148Z" } }, "answer": "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.", "b": { "slug": "outlook-mail-graph", "name": "Outlook Mail (Microsoft Graph)", "vendor": "Microsoft", "vendorUrl": "https://learn.microsoft.com/en-us/graph/api/resources/mail-api-overview", "kind": "http-api", "category": "mailbox-access", "summary": "Mail endpoints of Microsoft Graph for Outlook, Microsoft 365 and Exchange Online mailboxes. An app reads, searches, drafts, sends and files messages over REST with OAuth tokens from Microsoft Entra ID.", "url": "https://www.anchorterminal.com/tools/outlook-mail-graph", "markdownUrl": "https://www.anchorterminal.com/tools/outlook-mail-graph.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/outlook-mail-graph.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/outlook-mail-graph.json", "repo": "https://github.com/microsoftgraph/msgraph-sdk-javascript", "license": "MIT (SDKs)", "transports": [ "http" ], "remoteUrl": "https://graph.microsoft.com/v1.0", "packages": [ { "registry": "npm", "name": "@microsoft/microsoft-graph-client" }, { "registry": "pypi", "name": "msgraph-sdk" } ], "auth": "oauth", "authNotes": "OAuth 2.0 tokens from Microsoft Entra ID, after a person registers an app. No app review by Microsoft was found for mail permissions. Delegated permissions (Mail.ReadBasic, Mail.Read, Mail.ReadWrite, Mail.Send) act as a signed-in user and need only that user's consent. Application permissions reach every mailbox in a tenant, need admin consent, and can be limited to chosen mailboxes with RBAC for Applications in Exchange Online. Personal Outlook.com accounts work with delegated permissions.", "pricing": "byo-plan", "pricingNotes": "Mail calls aren't metered. The only metered Graph API is SharePoint and OneDrive `assignSensitivityLabel` at $0.00185 a call (https://learn.microsoft.com/en-us/graph/metered-api-list). A work mailbox needs an Exchange Online or Microsoft 365 licence, and Microsoft's plan price page refused our reader on 8 October 2026. A free personal Outlook.com account lets an agent start without a contract. The Microsoft 365 developer programme sandbox is free only to members who qualify, such as Visual Studio subscribers. The Mail MCP server needs a Microsoft 365 Copilot licence.", "priceSummary": "Your plan", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the Graph mail reference or the metered API list (checked 2026-10-08).", "endpoints": [] }, "toolCount": 10, "popularity": { "githubStars": 835, "npmWeekly": 2882852, "pypiWeekly": 1578201, "asOf": "2026-10-08" }, "docsUrl": "https://learn.microsoft.com/en-us/graph/api/resources/mail-api-overview", "openapi": "https://raw.githubusercontent.com/microsoftgraph/msgraph-metadata/master/openapi/v1.0/openapi.yaml", "capabilities": [ "mailbox.read", "mailbox.search", "mailbox.send", "mailbox.drafts", "mailbox.sync" ], "tags": [ "hosted", "official", "oauth", "openapi", "webhooks", "typescript", "python", "enterprise" ], "lastRelease": "2026-10-06", "graded": true, "anchor": { "graded": true, "score": 66.3, "grade": "B", "agentReady": false, "rank": 272, "ranked": true, "rankOf": 842, "categoryRank": 4, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 81, "maintenance": 76, "payments": 35, "reliability": 60, "schema": 93, "security": 71, "transparency": 75 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-08" }, "negative": -4, "negativeNotes": [ "2026-06-16: a fix for a token leak through URL userinfo host confusion was merged into msgraph-sdk-javascript and the version bumped to 3.0.8, but on 8 October 2026 npm still serves 3.0.7 from September 2023 and the repository has no published advisory. Exploiting it needs an attacker-influenced URL passed to the client (https://github.com/microsoftgraph/msgraph-sdk-javascript/commit/5438ae90f50ef15d3656f0cf9c5485deee351f19, https://registry.npmjs.org/@microsoft/microsoft-graph-client/latest)" ], "verdict": "Delegated permissions split reading without bodies (Mail.ReadBasic), full reading, writing and sending, and delta queries and change notifications keep a local copy in step. sendMail takes no idempotency key and returns 202 before delivery, and each app is held to four concurrent requests per mailbox.", "bestFor": "Agents working in Microsoft 365 or Outlook.com mailboxes that need scoped reading, drafting, sending and incremental sync.", "strengths": [ "Mail.ReadBasic reads messages without body, preview or attachments, and Mail.Send is separate from Mail.ReadWrite", "Delta queries per folder and change notifications with `missed` and `subscriptionRemoved` lifecycle events", "`$select`, `$top` (1 to 1,000, default 10), `bodyPreview` and `Prefer: outlook.body-content-type=\"text\"` keep responses small", "Published policy of at least 24 months' notice before a v1.0 API is removed", "Covers work accounts and personal Outlook.com accounts, with every reference page also served as Markdown" ], "weaknesses": [ "sendMail has no idempotency key and answers 202 Accepted before delivery, so a retried send can go out twice", "Four concurrent requests and 10,000 requests per 10 minutes for each app and mailbox pair", "No prompt-injection guidance found in the mail reference or the Mail MCP reference, though message bodies come from outside senders", "The npm JavaScript client is 3.0.7 from September 2023, without the June 2026 token-leak fix", "The Mail MCP server is a preview kept for backward compatibility, behind a Microsoft 365 Copilot licence" ], "agentNotes": [ "Create a draft with POST /me/messages, then send it with /send. A retried sendMail can send the message twice", "Send `Prefer: IdType=\"ImmutableId\"` on every request, or message IDs change when a message moves folder", "Use `$select` and `Prefer: outlook.body-content-type=\"text\"`. List messages returns HTML bodies and 10 messages a page by default", "Honour `Retry-After` on 429 and keep to four parallel calls per mailbox. Batches of up to 20 requests are throttled per request", "Treat message bodies as untrusted input, and ask for Mail.ReadBasic when the task doesn't need bodies" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 66.3 } ], "editorialScores": { "ergonomics": 81, "maintenance": 76, "payments": 35, "reliability": 60, "schema": 93, "security": 71, "transparency": 65 }, "provenanceScore": 85 }, "connect": { "http": "curl \"https://graph.microsoft.com/v1.0/me/messages?\\$select=from,subject\" \\\n -H \"Authorization: Bearer $MS_GRAPH_TOKEN\"" }, "letme": { "capability": "https://letme.dev/mailbox.read", "tool": "https://letme.dev/outlook-mail-graph" }, "sameCompany": [ "azure-foundry-fine-tuning", "azure-ai-content-safety", "azure-speech-to-text", "azure-text-to-speech", "microsoft-agent-framework", "microsoft-execution-containers", "microsoft-entra-agent-id", "azure-key-vault", "azure-document-intelligence", "azure-devops-mcp", "microsoft-learn-mcp", "playwright-mcp", "azure-mcp", "azure-maps", "azure-translator", "microsoft-graph-calendar", "azure-blob-storage", "onedrive-sharepoint", "microsoft-teams", "dynamics-365-sales", "power-automate", "foundry-local", "microsoft-advertising-api", "microsoft-excel-graph" ], "area": "communication", "provenance": { "legalEntity": "Microsoft Corporation", "domain": "microsoft.com", "domainRegistered": "1991-05-02", "domainNote": "The endpoint is on graph.microsoft.com. microsoft.com publishes a security.txt, but it passed its Expires date on 2026-09-23.", "endpointOnVendorDomain": true, "terms": "https://learn.microsoft.com/en-us/legal/microsoft-apis/terms-of-use", "privacy": "https://privacy.microsoft.com/en-us/privacystatement", "statusPage": "https://status.cloud.microsoft", "changelog": "https://developer.microsoft.com/en-us/graph/changelog", "securityTxt": "expired", "checked": "2026-10-08", "notes": [ "The Microsoft service health page at status.cloud.microsoft needs JavaScript to show anything.", "The Microsoft APIs terms of use say they were last updated in October 2025.", "privacy.microsoft.com answered our reader with 403 on 8 October 2026, so the privacy URL follows the Microsoft Graph calendar listing and wasn't reread.", "RDAP for microsoft.com gives a registration date of 1991-05-02." ], "score": 85 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/outlook-mail-graph.json", "live": { "slug": "outlook-mail-graph", "probe": { "target": "https://graph.microsoft.com/v1.0", "method": "get", "lastAt": "2026-10-09T11:46:36.412591278Z", "lastOk": true, "lastStatus": 200, "lastMs": 4, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 4, "p95ms24h": 18, "samples24h": 218, "samples30d": 218, "days": [ { "date": "2026-10-08", "probes": 93, "ok": 93 }, { "date": "2026-10-09", "probes": 125, "ok": 125 } ] }, "versions": [ { "registry": "github", "name": "microsoftgraph/msgraph-sdk-javascript", "version": "3.0.7", "released": "2023-09-19", "seenAt": "2026-10-08T16:24:30.348454398Z" }, { "registry": "npm", "name": "@microsoft/microsoft-graph-client", "version": "3.0.7", "seenAt": "2026-10-08T16:24:29.99296352Z" }, { "registry": "pypi", "name": "msgraph-sdk", "version": "1.64.0", "released": "2026-10-06", "seenAt": "2026-10-08T16:24:30.234677595Z" } ], "githubStars": 835, "npmWeekly": 2882852, "pypiWeekly": 1578201, "securityTxt": { "url": "https://microsoft.com/.well-known/security.txt", "state": "expired", "expires": "2026-09-23T16:00:00.000Z", "checkedAt": "2026-10-08T15:39:08.216544687Z" }, "updatedAt": "2026-10-09T11:46:36.412591278Z" } }, "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "Fastmail Pty Ltd", "b": "Microsoft", "name": "Vendor" }, { "a": "no (local only)", "b": "https://graph.microsoft.com/v1.0", "name": "Hosted endpoint" }, { "a": "HTTP", "b": "HTTP", "name": "Transports" }, { "a": "OAuth or key", "b": "OAuth", "name": "Auth" }, { "a": "Paid", "b": "Your plan", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "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", "b": "MIT (SDKs)", "name": "Licence" }, { "a": "none", "b": "10", "name": "Tools exposed" }, { "a": "yes", "b": "no", "name": "Read-only variant documented" }, { "a": "no", "b": "no", "name": "llms.txt" }, { "a": "2026-04-22", "b": "2026-10-06", "name": "Last release" }, { "a": "no date given", "b": "2025-10-01", "name": "Terms last updated" }, { "a": "no date given", "b": "2026-09-01", "name": "Privacy policy last updated" }, { "a": "not found in the text", "b": "yes", "name": "Customer content may train models" }, { "a": "not found in the text", "b": "yes", "name": "Terms restrict automated access" }, { "a": "yes", "b": "yes", "name": "Terms restrict benchmarking" }, { "a": "not found in the text", "b": "yes", "name": "Terms or service can change without notice" }, { "a": "not found in the text", "b": "not found in the text", "name": "Arbitration or class-action waiver" }, { "a": "123 stars", "b": "835 stars, 2.9M npm/wk, 1.6M PyPI/wk", "name": "Popularity" } ], "faq": [ { "answer": "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.", "question": "Which is better for AI agents, Fastmail API (JMAP) or Outlook Mail (Microsoft Graph)?" }, { "answer": "Fastmail API (JMAP) takes an API key or an OAuth sign-in. Outlook Mail (Microsoft Graph) uses an OAuth sign-in.", "question": "Do Fastmail API (JMAP) and Outlook Mail (Microsoft Graph) need an API key?" }, { "answer": "No hosted endpoint is listed for Fastmail API (JMAP). Outlook Mail (Microsoft Graph) has a hosted endpoint at https://graph.microsoft.com/v1.0.", "question": "Can an agent call Fastmail API (JMAP) and Outlook Mail (Microsoft Graph) without installing anything?" } ], "goodFor": [ { "aheadOn": null, "also": [ "No incidents deducted, where Outlook Mail (Microsoft Graph) loses 4 points for them" ], "goodFor": "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.", "slug": "fastmail", "watchFor": "The customer terms forbid programmatically generated email to addresses outside the account, and say the service is not for machine-to-machine workflows" }, { "aheadOn": [ "Reliability, 60 against 54", "Schema \u0026 documentation, 93 against 52", "Agent ergonomics, 81 against 73", "Security \u0026 auth, 71 against 60", "Payments \u0026 pricing, 35 against 30", "Maintenance \u0026 community, 76 against 26" ], "also": [ "A hosted endpoint, with nothing to install" ], "goodFor": "Agents working in Microsoft 365 or Outlook.com mailboxes that need scoped reading, drafting, sending and incremental sync.", "slug": "outlook-mail-graph", "watchFor": "sendMail has no idempotency key and answers 202 Accepted before delivery, so a retried send can go out twice" } ], "job": { "capability": "mailbox.read", "name": "Mailbox read" }, "others": [ { "json": "https://www.anchorterminal.com/compare/emailengine-vs-fastmail.json", "title": "EmailEngine vs Fastmail API (JMAP)", "url": "https://www.anchorterminal.com/compare/emailengine-vs-fastmail" }, { "json": "https://www.anchorterminal.com/compare/emailengine-vs-outlook-mail-graph.json", "title": "EmailEngine vs Outlook Mail (Microsoft Graph)", "url": "https://www.anchorterminal.com/compare/emailengine-vs-outlook-mail-graph" }, { "json": "https://www.anchorterminal.com/compare/fastmail-vs-gmail-api.json", "title": "Fastmail API (JMAP) vs Gmail API", "url": "https://www.anchorterminal.com/compare/fastmail-vs-gmail-api" }, { "json": "https://www.anchorterminal.com/compare/fastmail-vs-nylas-email.json", "title": "Fastmail API (JMAP) vs Nylas Email API", "url": "https://www.anchorterminal.com/compare/fastmail-vs-nylas-email" }, { "json": "https://www.anchorterminal.com/compare/fastmail-vs-unipile.json", "title": "Fastmail API (JMAP) vs Unipile", "url": "https://www.anchorterminal.com/compare/fastmail-vs-unipile" }, { "json": "https://www.anchorterminal.com/compare/fastmail-vs-zoho-mail.json", "title": "Fastmail API (JMAP) vs Zoho Mail API", "url": "https://www.anchorterminal.com/compare/fastmail-vs-zoho-mail" }, { "json": "https://www.anchorterminal.com/compare/gmail-api-vs-outlook-mail-graph.json", "title": "Gmail API vs Outlook Mail (Microsoft Graph)", "url": "https://www.anchorterminal.com/compare/gmail-api-vs-outlook-mail-graph" }, { "json": "https://www.anchorterminal.com/compare/nylas-email-vs-outlook-mail-graph.json", "title": "Nylas Email API vs Outlook Mail (Microsoft Graph)", "url": "https://www.anchorterminal.com/compare/nylas-email-vs-outlook-mail-graph" }, { "json": "https://www.anchorterminal.com/compare/outlook-mail-graph-vs-unipile.json", "title": "Outlook Mail (Microsoft Graph) vs Unipile", "url": "https://www.anchorterminal.com/compare/outlook-mail-graph-vs-unipile" }, { "json": "https://www.anchorterminal.com/compare/outlook-mail-graph-vs-zoho-mail.json", "title": "Outlook Mail (Microsoft Graph) vs Zoho Mail API", "url": "https://www.anchorterminal.com/compare/outlook-mail-graph-vs-zoho-mail" } ], "scores": [ { "by": 6, "edge": "outlook-mail-graph", "fastmail": 54, "key": "reliability", "name": "Reliability", "outlook-mail-graph": 60, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 41, "edge": "outlook-mail-graph", "fastmail": 52, "key": "schema", "name": "Schema \u0026 documentation", "outlook-mail-graph": 93, "weight": 13 }, { "by": 8, "edge": "outlook-mail-graph", "fastmail": 73, "key": "ergonomics", "name": "Agent ergonomics", "outlook-mail-graph": 81, "weight": 13 }, { "by": 11, "edge": "outlook-mail-graph", "fastmail": 60, "key": "security", "name": "Security \u0026 auth", "outlook-mail-graph": 71, "weight": 14 }, { "by": 5, "edge": "outlook-mail-graph", "fastmail": 30, "key": "payments", "name": "Payments \u0026 pricing", "outlook-mail-graph": 35, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 50, "edge": "outlook-mail-graph", "fastmail": 26, "key": "maintenance", "name": "Maintenance \u0026 community", "outlook-mail-graph": 76, "weight": 7 }, { "by": 1, "edge": "outlook-mail-graph", "fastmail": 74, "key": "transparency", "name": "Transparency \u0026 trust", "outlook-mail-graph": 75, "weight": 7 } ], "summary": "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.", "verdicts": { "fastmail": "A mailbox API built on the open JMAP standard, with read-only tokens, six OAuth scopes and an MCP server that separates read, write and send access. Fastmail publishes no OpenAPI file, SDK, API changelog, request rate limit or SLA, and its customer terms forbid programmatically generated email to addresses outside the account.", "outlook-mail-graph": "Delegated permissions split reading without bodies (Mail.ReadBasic), full reading, writing and sending, and delta queries and change notifications keep a local copy in step. sendMail takes no idempotency key and returns 202 before delivery, and each app is held to four concurrent requests per mailbox." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph", "json": "https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph.md", "slim": "https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph.min.md" }, "markdown": "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.\n\n- Fastmail API (JMAP): grade C, 54.1/100, rank #620 of 842. Markdown https://www.anchorterminal.com/tools/fastmail.md · JSON https://www.anchorterminal.com/api/v1/tools/fastmail.json\n- Outlook Mail (Microsoft Graph): grade B, 66.3/100, rank #272 of 842. Markdown https://www.anchorterminal.com/tools/outlook-mail-graph.md · JSON https://www.anchorterminal.com/api/v1/tools/outlook-mail-graph.json\n\n## Which one, for what\n\n### Fastmail API (JMAP) (C)\n\nGood 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.\n\nAlso in its favour:\n- No incidents deducted, where Outlook Mail (Microsoft Graph) loses 4 points for them\n\nWatch for: The customer terms forbid programmatically generated email to addresses outside the account, and say the service is not for machine-to-machine workflows\n\n### Outlook Mail (Microsoft Graph) (B)\n\nGood for: Agents working in Microsoft 365 or Outlook.com mailboxes that need scoped reading, drafting, sending and incremental sync.\n\nAhead on:\n- Reliability, 60 against 54\n- Schema \u0026 documentation, 93 against 52\n- Agent ergonomics, 81 against 73\n- Security \u0026 auth, 71 against 60\n- Payments \u0026 pricing, 35 against 30\n- Maintenance \u0026 community, 76 against 26\n\nAlso in its favour:\n- A hosted endpoint, with nothing to install\n\nWatch for: sendMail has no idempotency key and answers 202 Accepted before delivery, so a retried send can go out twice\n\n\n## Score by category\n\n| Category | Weight | Fastmail API (JMAP) | Outlook Mail (Microsoft Graph) | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 54 | 60 | Outlook Mail (Microsoft Graph) +6 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 52 | 93 | Outlook Mail (Microsoft Graph) +41 |\n| Agent ergonomics | 13% (16.2 this run) | 73 | 81 | Outlook Mail (Microsoft Graph) +8 |\n| Security \u0026 auth | 14% (17.5 this run) | 60 | 71 | Outlook Mail (Microsoft Graph) +11 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 30 | 35 | Outlook Mail (Microsoft Graph) +5 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 26 | 76 | Outlook Mail (Microsoft Graph) +50 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 74 | 75 | Outlook Mail (Microsoft Graph) +1 |\n| Negative events | ≤15 | 0 | -4 | |\n| **Total** | | **54.1 · C** | **66.3 · B** | |\n\n## Facts side by side\n\n| Fact | Fastmail API (JMAP) | Outlook Mail (Microsoft Graph) |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Fastmail Pty Ltd | Microsoft |\n| Hosted endpoint | no (local only) | `https://graph.microsoft.com/v1.0` |\n| Transports | HTTP | HTTP |\n| Auth | OAuth or key | OAuth |\n| Pricing | Paid | Your plan |\n| x402 | no | no |\n| 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) |\n| Tools exposed | none | 10 |\n| Read-only variant documented | yes | no |\n| llms.txt | no | no |\n| Last release | 2026-04-22 | 2026-10-06 |\n| Terms last updated | no date given | 2025-10-01 |\n| Privacy policy last updated | no date given | 2026-09-01 |\n| Customer content may train models | not found in the text | yes |\n| Terms restrict automated access | not found in the text | yes |\n| Terms restrict benchmarking | yes | yes |\n| Terms or service can change without notice | not found in the text | yes |\n| Arbitration or class-action waiver | not found in the text | not found in the text |\n| Popularity | 123 stars | 835 stars, 2.9M npm/wk, 1.6M PyPI/wk |\n\n## Verdicts\n\n**Fastmail API (JMAP).** A mailbox API built on the open JMAP standard, with read-only tokens, six OAuth scopes and an MCP server that separates read, write and send access. Fastmail publishes no OpenAPI file, SDK, API changelog, request rate limit or SLA, and its customer terms forbid programmatically generated email to addresses outside the account.\n\n**Outlook Mail (Microsoft Graph).** Delegated permissions split reading without bodies (Mail.ReadBasic), full reading, writing and sending, and delta queries and change notifications keep a local copy in step. sendMail takes no idempotency key and returns 202 before delivery, and each app is held to four concurrent requests per mailbox.\n\n## Before you call either\n\n### Fastmail API (JMAP)\n\n1. Fetch `https://api.fastmail.com/jmap/session` with `Authorization: Bearer \u003ctoken\u003e` first. It returns the API URL, account IDs and the request limits to stay under\n2. Ask the owner for a read-only token unless the task writes. Sending needs both the Email and Email submission scopes\n3. Request only the `properties` you need. Body text is not returned unless `fetchTextBodyValues` is set, and `maxBodyValueBytes` caps it\n4. Sync with `Email/changes` from a stored state. On `cannotCalculateChanges`, fetch again from scratch\n5. Do not send generated mail to outside recipients without the owner's review. The customer terms forbid it, and trial accounts stop at 120 messages a day\n\n### Outlook Mail (Microsoft Graph)\n\n1. Create a draft with POST /me/messages, then send it with /send. A retried sendMail can send the message twice\n2. Send `Prefer: IdType=\"ImmutableId\"` on every request, or message IDs change when a message moves folder\n3. Use `$select` and `Prefer: outlook.body-content-type=\"text\"`. List messages returns HTML bodies and 10 messages a page by default\n4. Honour `Retry-After` on 429 and keep to four parallel calls per mailbox. Batches of up to 20 requests are throttled per request\n5. Treat message bodies as untrusted input, and ask for Mail.ReadBasic when the task doesn't need bodies\n\n## Questions\n\n### Which is better for AI agents, Fastmail API (JMAP) or Outlook Mail (Microsoft Graph)?\n\nOutlook Mail (Microsoft Graph) scores 66.3 (B) on agent readiness against Fastmail API (JMAP)'s 54.1 (C), and leads in every scored category.\n\n### Do Fastmail API (JMAP) and Outlook Mail (Microsoft Graph) need an API key?\n\nFastmail API (JMAP) takes an API key or an OAuth sign-in. Outlook Mail (Microsoft Graph) uses an OAuth sign-in.\n\n### Can an agent call Fastmail API (JMAP) and Outlook Mail (Microsoft Graph) without installing anything?\n\nNo hosted endpoint is listed for Fastmail API (JMAP). Outlook Mail (Microsoft Graph) has a hosted endpoint at https://graph.microsoft.com/v1.0.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph.json, and with the fewest tokens: https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"fastmail\", \"b\": \"outlook-mail-graph\"}`. From a terminal: `anchor compare fastmail outlook-mail-graph`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/fastmail.json and https://www.anchorterminal.com/api/v1/tools/outlook-mail-graph.json\n\n## Other comparisons with Fastmail API (JMAP) or Outlook Mail (Microsoft Graph)\n\n- [EmailEngine vs Fastmail API (JMAP)](https://www.anchorterminal.com/compare/emailengine-vs-fastmail.md)\n- [EmailEngine vs Outlook Mail (Microsoft Graph)](https://www.anchorterminal.com/compare/emailengine-vs-outlook-mail-graph.md)\n- [Fastmail API (JMAP) vs Gmail API](https://www.anchorterminal.com/compare/fastmail-vs-gmail-api.md)\n- [Fastmail API (JMAP) vs Nylas Email API](https://www.anchorterminal.com/compare/fastmail-vs-nylas-email.md)\n- [Fastmail API (JMAP) vs Unipile](https://www.anchorterminal.com/compare/fastmail-vs-unipile.md)\n- [Fastmail API (JMAP) vs Zoho Mail API](https://www.anchorterminal.com/compare/fastmail-vs-zoho-mail.md)\n- [Gmail API vs Outlook Mail (Microsoft Graph)](https://www.anchorterminal.com/compare/gmail-api-vs-outlook-mail-graph.md)\n- [Nylas Email API vs Outlook Mail (Microsoft Graph)](https://www.anchorterminal.com/compare/nylas-email-vs-outlook-mail-graph.md)\n- [Outlook Mail (Microsoft Graph) vs Unipile](https://www.anchorterminal.com/compare/outlook-mail-graph-vs-unipile.md)\n- [Outlook Mail (Microsoft Graph) vs Zoho Mail API](https://www.anchorterminal.com/compare/outlook-mail-graph-vs-zoho-mail.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-09", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.4", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Fastmail API (JMAP) vs Outlook Mail (Microsoft Graph)", "url": "" } ], "description": "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.", "facts": [ "Fastmail API (JMAP) C 54.1", "Outlook Mail (Microsoft Graph) B 66.3", "scores" ], "h1": "Fastmail API (JMAP) vs Outlook Mail (Microsoft Graph)", "image": "https://www.anchorterminal.com/assets/og/compare-fastmail-vs-outlook-mail-graph.png", "path": "/compare/fastmail-vs-outlook-mail-graph", "published": "2026-10-01", "section": "tools", "title": "Fastmail API (JMAP) vs Outlook Mail (Microsoft Graph) for AI agents", "toc": null, "updated": "2026-10-09", "url": "https://www.anchorterminal.com/compare/fastmail-vs-outlook-mail-graph" }, "tokens": { "markdown": 2300, "slim": 730 }, "version": 1 }