Head to head · Mailbox access · October 2026 research run
email-agent-mcp vs Zoho Mail API
email-agent-mcp scores 65.9 (B) on agent readiness against Zoho Mail API's 49.6 (D), and leads in 5 of 7 scored categories. Zoho Mail API leads on transparency & trust. Both do mailbox access.
Best mailbox access APIs for AI agents · All 55 mailboxes comparisons
Which one, for what
Best for A person who wants an agent working in their own Outlook mailbox, or reading and drafting in Gmail, with guardrails.
Ahead on
- Reliability, 50 against 42
- Schema & documentation, 79 against 45
- Agent ergonomics, 79 against 56
- Payments & pricing, 60 against 30
- Maintenance & community, 84 against 33
Also in its favour
- Runs on your own machine
- Open source
Watch for
Pre-1.0, and every commit is by one maintainer
Best for An agent working inside its owner's Zoho Mail mailbox or administering a Zoho Mail organisation, where narrow scopes and the MCP server keep access small.
Ahead on
- Transparency & trust, 73 against 42
Also in its favour
- Free to start without a card
Watch for
The Zoho Mail usage policy, updated 2 September 2026, lists automated, bulk and transactional emails among uses that are not allowed.
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.
Maintenance & community email-agent-mcp +51
email-agent-mcp 84
v0.5.0 was tagged and published on 5 November 2026 (30). Nine npm releases in the 90 days from 8 August, v0.3.0 to v0.5.0 (20). Pull requests up to #234 merged in the history, all by the one maintainer; issue responses couldn't be read through GitHub's API that day (10 of 25). io.github.UseJunior/email-agent-mcp is in the official MCP registry with 0.5.0 marked latest (15). CI, commitlint, semgrep and Codecov workflows (9 of 10). Total 84.
Zoho Mail API 33
Zoho keeps no API changelog, so recency rests on What's New entries for functions the REST API serves, dated by month only. What's New (Last-Modified 2 November 2026) lists from August to October 2026 two such entries, subfolders in the Archive folder (August, Folders API) and flagged emails added as tasks (October, Tasks API). The rest are web, mobile or admin-console functions the API doesn't serve (TLS policies, MTA-STS, display and settings screens). October lies 4 to 34 days back, within 90 but not shown within 30 (20). Two entries in the window from 6 August, fewer than three (0). The pricing page states support by email, chat and phone around the clock, and the changelog is public. The community forum wasn't tested for replies (9 of 15 for a closed service). No REST SDK. A Java command line tool and the MCP server are official. The MCP registry was not checked (4 of 15). No public repository, package or CI was found (0 of 10). 20 + 0 + 9 + 4 + 0 = 33.
Schema & documentation email-agent-mcp +34
email-agent-mcp 79
Tools are defined with typed input schemas that the MCP SDK publishes as JSON Schema (25). README in five languages, AGENTS.md, CLAUDE.md and GEMINI.md; no llms.txt, which a local server doesn't need (5 of 10). The README's tool table marks each tool read, write or destructive and states provider limits, such as Gmail deletes removing drafts only (15 of 20). Typed inputs with options such as list_style (12 of 15). Setup examples per client and documented error behaviour, such as NOT_SUPPORTED on Gmail and sanitised errors (10 of 15). Semver tags and GitHub Releases (12 of 15). Total 79.
Zoho Mail API 45
Graded on the REST API. No OpenAPI or similar file was found in the docs or under the zoho organisation on GitHub. The MCP tool definitions sit in a signed-in console and were not read (0 of 25). https://www.zoho.com/mail/help/llms.txt indexes a Markdown twin of every reference page (10). Each page states the purpose and names the call that supplies each ID, with little on when not to use a call (13 of 20). Parameters are listed with a type, a mandatory mark, allowed values and defaults, in prose only. Many PUT calls share one URL and differ by a mode field, and sample responses carry numbers and booleans as strings (9 of 15). Every page has a curl sample and a sample response. Errors are one shared list of seven status codes, with nothing per endpoint (9 of 15). The path has no version. What's New is a product changelog dated by month, and no API changelog was found (4 of 15).
Transparency & trust Zoho Mail API +31
email-agent-mcp 42
Apache-2.0 with a LICENSE file (30). SECURITY.md says tokens and mail are handled locally over stdio with no network listener, and the broker README says mail never reaches the broker and refresh tokens aren't stored. The broker has no published privacy policy (22 of 30). No deprecation policy (0). No telemetry was found in the README or package manifests, and none is stated either way (10 of 20). Total 62.
Zoho Mail API 73
The editorial half. A closed service under the Zoho Terms of Service, last updated 2 March 2022, and a Zoho Mail usage policy updated 2 September 2026. No source repository (15 of 30). The privacy policy of 22 December 2025 says Zoho does not sell personal information, and that account data leaves the active database at a clean-up run every six months after termination and backups three months later. It also says anonymised crops of service data are used to improve algorithms and that staff may manually verify emails reported as spam, while the Zoho Mail privacy page says Zoho will never read a customer's emails. The DPA is sent on request by email (21 of 30). No API deprecation policy or dated notices were found (0 of 20). A sub-processor page exists, but its list loads by script and was not read. The data centre page names 20 sites and the certifications of each (15 of 20). The provenance half is computed from the provenance block.
Payments & pricing email-agent-mcp +30
email-agent-mcp 60
Free, Apache-2.0 software with nothing to buy, scored 20 + 20 + 20 by the self-hosted rule. No payment protocol (0 of 40). Total 60.
Zoho Mail API 30
No x402, MPP or L402 (0 of 40). Plan prices are rendered on the pricing page without a login, $1 to $6 a user a month billed yearly, with API access included and no per-call price (10 of 20). Mail Free covers five users with no card, in some regions only, and the highest paid edition has a 15-day trial with no card (20). A person signs up in a browser, registers an OAuth client in the API console and approves scopes (0 of 20). 0 + 10 + 20 + 0 = 30.
Agent ergonomics email-agent-mcp +23
email-agent-mcp 79
27 tools in the full profile, the 11 to 30 band, plus the observe profile as a read-only subset (20 of 25). List and search tools filter and page; we read the tool table, not every parameter (16 of 20). Errors are sanitised and use stable reasons such as NOT_SUPPORTED, failing closed before a Gmail mutation (15 of 20). readOnlyHint and destructiveHint on the tools in source; sends take no idempotency key (16 of 20). One npx command and a setup wizard for OAuth and mailbox choice; TypeScript only (12 of 15). Total 79.
Zoho Mail API 56
Graded on the REST API. List and search return a summary per message and the body is a separate call, with limit from 1 to 200 and a default of 10. There is no field selection. In MCP the owner chooses which tools a server carries, and the tool count is not published (17 of 25). start and limit, filters for folder, read status, flag, label, thread and attachments, three sort keys and a search syntax (18 of 20). Errors carry a status code, a description and a moreInfo message. Seven codes are documented, with no list of messages or recovery steps (10 of 20). No idempotency key or conditional write was found, so a retried send can go out twice. Delete moves to Trash unless expunge=true. MCP annotations were not read (5 of 20). Send needs only fromAddress and toAddress, and defaults are stated. No REST SDK in any language, tokens last an hour, hosts differ by data centre, and reading a body needs an account ID, a folder ID and a message ID (6 of 15).
Reliability email-agent-mcp +8
email-agent-mcp 50
Graded with the lines for local packages and stdio MCP servers. Installs from the official npm package email-agent-mcp with npx, CI runs on Node 20 (20). A CI workflow with Vitest tests, Codecov and a spec-coverage gate; the run results weren't readable through GitHub's API that day, so partial (20 of 25). Open crash and regression issues couldn't be read because GitHub's API refused our requests for its rate limit (0, unchecked). Semver tags from v0.1.7 to v0.5.0 and auto-categorised GitHub Releases as the changelog, with no breaking changes marked in what we read (10 of 15). Pre-1.0 (0). Total 50.
Zoho Mail API 42
Graded on the REST API, read with the hosted lines. status.zoho.com redirects to us.zohostatus.com, which listed components for Zoho Mail, mail listing, IMAP, POP, SMTP and the MX host on 9 October. The status-page line keeps its 20, as on the other Zoho listings. us.zohostatus.com now answers robots.txt with an access-denied page, so the 9 October incident readings are struck and no history is readable (5). The getting started guide (Last-Modified 8 January 2026) says each API has its own rate limit and gives no numbers. Sending limits are published, 50 to 500 external emails an hour and 1,000 internal. Kept as a partial (7). The response code list has no 429, and no Retry-After, backoff guidance or idempotency key was found. The guide says only that the response will say when a limit is exceeded, which is no handling guidance (0). The pricing page lists a 99.9% uptime guarantee with no SLA document, measurement or credit terms, and a listed SLA figure with no document gives 0 in this run (0). The API carries no beta or preview label (10). 20 + 5 + 7 + 0 + 0 + 10 = 42.
Score by category
| Category | Weight this run | email-agent-mcp | Zoho Mail API | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 50 | 42 | email-agent-mcp +8 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 79 | 45 | email-agent-mcp +34 |
| Agent ergonomics | 13%16.2 | 79 | 56 | email-agent-mcp +23 |
| Security & auth | 14%17.5 | 67 | 67 | even |
| Payments & pricing | 10%12.5 | 60 | 30 | email-agent-mcp +30 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 84 | 33 | email-agent-mcp +51 |
| Transparency & trust | 7%8.8 | 42 | 73 | Zoho Mail API +31 |
| Negative events | ≤15 | 0 | 0 | |
| Total | B 65.9/100 | D 49.6/100 |
Facts side by side
| Fact | email-agent-mcp | Zoho Mail API |
|---|---|---|
| Kind | MCP server | HTTP API |
| Vendor | UseJunior | Zoho |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | stdio | HTTP |
| Auth | OAuth | OAuth |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 | Proprietary service under the Zoho Terms of Service and the Zoho Mail usage policy. No source repository was found |
| Tools exposed | 27 | none |
| Read-only variant documented | yes | no |
| llms.txt | no | yes |
| MCP registry | io.github.UseJunior/email-agent-mcp | not listed |
| Last release | 2026-11-05 | none |
| Terms last updated | no document linked | 2022-03-02 |
| Privacy policy last updated | no document linked | 2025-12-22 |
| Customer content may train models | not read yet | yes |
| Terms restrict automated access | not read yet | not found in the text |
| Terms restrict benchmarking | not read yet | yes |
| Terms or service can change without notice | not read yet | not found in the text |
| Arbitration or class-action waiver | not read yet | not found in the text |
| Popularity | 394 npm/wk | none |
How the scores have moved
email-agent-mcp
No score change since it was listed.
Verdicts
email-agent-mcp
A local MCP server for a person's own Outlook or Gmail mailbox with careful defaults, a read-only scope profile, send allowlists, gated deletes and annotated tools, released weekly under Apache-2.0. It is pre-1.0 from one maintainer, Gmail lacks label and move support, and Gmail sign-in relies on UseJunior's hosted broker.
Zoho Mail API
A REST API over a Zoho Mail mailbox with OAuth scopes that narrow to one resource and one operation, plus an MCP server launched in 2026. Zoho publishes no OpenAPI file, SDK, request rate limit or API changelog, and its usage policy bars automated email.
Before you call either
email-agent-mcp
- Start with
get_mailbox_status, thenlist_emailsorsearch_emailsbefore reading whole threads - Ask the person to set the send allowlist before planning any
send_emailorreply_to_email - Prefer
create_draftand let the person send, unless they asked for sending - Expect NOT_SUPPORTED for label, flag, mark-read and move on Gmail, and don't request
gmail.modifyto work around it - Don't plan deletes; they need an operator environment variable and a caller flag
Zoho Mail API
- Send
Authorization: Zoho-oauthtoken <token>, notBearer. The token response saysBearer, but the OAuth guide says the Mail API requires the Zoho prefix. - Use the host for the account's data centre, such as
mail.zoho.euormail.zoho.in. CallGET /api/accountsfirst for theaccountIdevery mailbox call needs. - Reading a message body needs both
folderIdandmessageId. List and search calls return a summary only, 10 messages by default and 200 at most. - Request
ZohoMail.messages.READalone for a reading agent. AddCREATEonly when it must send, and leaveDELETEout unless required. - Refresh the access token every hour, and post OAuth parameters in the request body where the server accepts it, to keep secrets out of URLs.
Questions
Which is better for AI agents, email-agent-mcp or Zoho Mail API?
email-agent-mcp scores 65.9 (B) on agent readiness against Zoho Mail API's 49.6 (D), and leads in 5 of 7 scored categories. Zoho Mail API leads on transparency & trust.
Do email-agent-mcp and Zoho Mail API need an API key?
Both use an OAuth sign-in.
Can an agent call email-agent-mcp and Zoho Mail API without installing anything?
email-agent-mcp runs on your own machine, with no hosted endpoint listed. No hosted endpoint is listed for Zoho Mail API.
Are email-agent-mcp and Zoho Mail API open source?
email-agent-mcp is open source (Apache-2.0). No open-source release is listed for Zoho Mail API.
Other comparisons with email-agent-mcp or Zoho Mail API
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- email-agent-mcp vs Fastmail API (JMAP)
- email-agent-mcp vs Gmail API
- email-agent-mcp vs Himalaya
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- email-agent-mcp vs Outlook Mail (Microsoft Graph)
- email-agent-mcp vs Unipile
- EmailEngine vs Zoho Mail API
- Fastmail API (JMAP) vs Zoho Mail API
- Gmail API vs Zoho Mail API
- Himalaya vs Zoho Mail API
- Nylas Email API vs Zoho Mail API
- Outlook Mail (Microsoft Graph) vs Zoho Mail API
- Unipile vs Zoho Mail API
Machine-readable
- This page as Markdown
/compare/email-agent-mcp-vs-zoho-mail.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/email-agent-mcp.json·/api/v1/tools/zoho-mail.json - From a terminal
anchor compare email-agent-mcp zoho-mail(the CLI) - Over MCP
compare_tools {"a": "email-agent-mcp", "b": "zoho-mail"}at/mcp, no key