Warmerly
REST API and webhooks on the Agency plan only; an MCP server on every plan.
Warmerly
Warmup Inbox
One-to-one · API access
API access
One row, in depth: what each tool does, the verified numbers, and who each suits.
Warmup Inbox details read from its pricing page, home page, product pages, API page, integrations pages, help centre, legal pages and status page on 21 October 2026.
Warmerly
REST API and webhooks on the Agency plan only; an MCP server on every plan.
Warmup Inbox
An API on the trial and any paid plan, 120 requests a minute, with interactive docs and a Postman collection.
The short answer
API access, in one look.
Warmup Inbox's API is available on the 7-day trial and on any paid plan, with a key in an x-api-key header, 120 requests a minute, an interactive reference and a Postman collection. Warmerly's REST API, API keys and webhooks need the Agency plan at $179 a month; Free, Starter and Growth get a 403, though an MCP server works on every plan including Free. For a small team that wants to script warmup, Warmup Inbox is the easier and cheaper way in. Warmerly's extras are signed health webhooks and a wider API that covers campaigns and leads. Last checked 21 October 2026.
Warmup InboxWarmup Inbox ahead on this row
An API on the trial and any paid plan, 120 requests a minute, with interactive docs and a Postman collection.
The picture
Drawn side by side.
How Warmerly does it
Warmerly, in detail.
A REST API, keys and signed webhooks on Agency only, covering twelve areas from mailboxes and campaigns to warmup and workspaces, plus an MCP server on every plan.
01
Agency plan only
API keys, the API itself and webhooks need the Agency plan, $179 a month for 100 mailboxes. Free, Starter and Growth get a 403 agency_plan_required error. The 7-day Agency trial includes API access, so an integration can be tested before the first charge.
Warmerly product, checked 21 October 2026
02
Keys
Keys start with wmv_, go in an X-Api-Key header to https://app.warmerly.com/api/v1 and are shown once. Each user can hold up to 10 active keys. Only a SHA-256 hash is stored. A key carries the full access of the person who made it, with no per-endpoint scopes and no read-only keys.
Warmerly product, checked 21 October 2026
03
Rate limits
60 requests a minute per key by default, set between 1 and 120 at creation, and capped at 120 whatever the plan. Over the limit returns a 429 too_many_requests. Lead search has an extra limit of 120 requests per 5 minutes per user. Monthly plan allowances return a 402, not a 429.
Warmerly product, checked 21 October 2026
04
What it covers
Reference pages exist for 12 areas: accounts (mailboxes), campaigns, leads, inbox, suppression, usage, email verification, email finder, warmup, workspaces, API keys and webhooks. Everything the API does is also in the dashboard.
Warmerly product, checked 21 October 2026
05
Webhooks: 16 mailbox health events
Signed POSTs for mailbox health events such as score_drop, auth_fail, auto_paused and aged_in. They do not cover opens, clicks or replies. Agency only, with up to 10 subscriptions per user. The X-Warmerly-Signature header is the hex HMAC-SHA256 of the raw body.
Warmerly product, checked 21 October 2026
06
Delivery rules
Each delivery is tried up to 3 times, with 0.5 and then 1 second between attempts, and a failed event is not redelivered later. A subscription switches itself off after 10 consecutive sweeps in which a delivery failed, and a PATCH re-enables it.
Warmerly product, checked 21 October 2026
07
MCP on every plan
An MCP server at /api/mcp signs in with OAuth 2.1, needs no API key and works on every plan including Free. Reads and writes share 60 calls a minute per connection, and no tool can start or resume campaign sending.
Warmerly product, checked 21 October 2026
How Warmup Inbox does it
Warmup Inbox, in detail.
A REST API for the warmup lifecycle: inboxes, metrics, templates, tags and plans, with a single 120 a minute limit, no webhooks mentioned, and a trial that can generate a key.
01
Access and authentication
The API page says to create an account, with the 7-day free trial working, and generate a key inside the app. You send it in the x-api-key header, and every endpoint lives under api.warmupinbox.com/v1 and returns JSON over HTTPS.
warmupinbox.com/api-access · read 21 October 2026
02
Six documented endpoints
The page names POST /v1/inboxes, POST /v1/inboxes/advanced for any SMTP and IMAP mailbox, GET /v1/inboxes/{id}/metrics, POST /v1/email-templates, GET /v1/tags and PATCH /v1/inboxes/{id}/plan. Other actions are described without paths.
warmupinbox.com/api-access · read 21 October 2026
03
What you can do
Create, update, start, pause and delete inboxes, connect mailboxes over SMTP and IMAP or OAuth, pull placement metrics for any timeframe, manage templates, topics and tags, switch plans per inbox and check account credits.
warmupinbox.com/api-access · read 21 October 2026
04
One rate limit
120 requests a minute. Requests beyond it are temporarily blocked until it resets, so the page tells you to build retry logic with backoff. No per-plan rate limit is given.
warmupinbox.com/api-access · read 21 October 2026
05
Plan-dependent parts
Reply-rate caps scale with the plan: up to 25% on Basic, 45% on Pro and 65% on Max on this page. Email topics, custom templates and per-inbox schedules with timezone control are on Pro and Max. The pricing page lists a developers API on Basic and an unlimited one on Max.
warmupinbox.com/api-access · read 21 October 2026
06
Documentation
An interactive reference at api.warmupinbox.com/api-doc covers each endpoint with request parameters, response schemas and error codes. A Postman collection has requests and snippets for Node.js and Python, and the reference is available as machine-readable JSON for OpenAPI tools.
warmupinbox.com/api-access · read 21 October 2026
07
Partners
The page offers partner access for integration partners who want to offer warmup inside their own product, backed by the stated network of 30,000+ inboxes. It gives no terms.
warmupinbox.com/api-access · read 21 October 2026
What Warmup Inbox does not say
We looked, and found no statement on these. That is about its published pages only, not about the product.
- Webhooks, which the API page does not mention
- Endpoint paths for start, pause, update and delete, or for the credits check
- What limited means for the developers API on Basic
- Per-key scopes or read-only keys
- A deprecation or versioning policy beyond the v1 prefix
- A rate limit that differs by plan, or a per-day cap
Where the sources disagree
We report each version rather than pick one.
- The API page gives 65% as Max's reply-rate cap, while the pricing page and a help article give 50%.
- The API page says the API is available on the trial or any paid plan, while its Instantly comparison page lists API access under Max and the pricing page lists unlimited API under Max only.
- The API page says everything below ships today in v1 with each endpoint documented, and gives paths for six of the actions it lists.
The numbers
Only what we could verify.
| Measure | Warmerly | Warmup Inbox |
|---|---|---|
| API access | REST API and webhooks on the Agency plan only; an MCP server on every plan. | An API on the trial and any paid plan, 120 requests a minute, with interactive docs and a Postman collection. |
| Plan needed | Agency, $179 a month | Trial or any paid plan |
| Rate limit | 60 a minute by default, up to 120 | 120 a minute |
| Auth header | X-Api-Key, key shown once | x-api-key, generated in the app |
| Areas documented | 12 reference areas | Inboxes, metrics, templates, tags, plans |
| Webhooks | 16 mailbox health events, Agency only | Not mentioned |
| Postman collection | Not stated; docs and llms.txt published | Yes, with Node.js and Python snippets |
| Keys per user | Up to 10 active | Not stated |
| AI assistants | MCP server on every plan, OAuth 2.1 | Not mentioned |
In practice
What it means for you.
Our reading of the facts above. Not a promise, and not the only reasonable reading.
The entry price of an API differs sharply
To call Warmerly's API you need Agency at $179 a month, or a 7-day Agency trial. To call Warmup Inbox's you need a trial or Basic. If you are one developer scripting a handful of inboxes, that is a real difference and it is in Warmup Inbox's favour.
What each API is about
Warmup Inbox's is about warmup: inboxes, metrics, templates. Warmerly's reaches campaigns, leads, inbox, suppression and verification as well, because the product does more. If you only want warmup in your own dashboard, the smaller surface is enough.
Webhooks on one side only, and only for health
Warmerly's signed webhooks push mailbox health events to you. We found none on Warmup Inbox's page. If you want to be told when a score drops without polling, that matters. They do not send opens or replies.
Rate limits are close
Warmerly defaults to 60 a minute and tops out at 120, which is Warmup Inbox's single figure. Our arithmetic gives at most 7,200 an hour at the top setting. Neither is built for bulk pulls of every inbox's history every minute.
MCP is a different door
Warmerly's MCP server lets Claude, ChatGPT, Cursor and other clients work in your workspace on any plan. It is not an API key and cannot start or resume campaign sending. We found no equivalent on Warmup Inbox's pages.
Who it suits
Pick the one that fits.
Warmerly
Warmerly is the better fit if
- You are on or heading to the Agency plan and want one API for warmup, campaigns and leads
- You want signed webhooks for mailbox health events
- You want an MCP server for AI assistants, on a free plan too
- You want keys that are shown once and stored only as a hash
- You want published docs in Markdown and llms.txt for machines
Warmup Inbox
Warmup Inbox is the better fit if
- You want an API on a trial or a low plan
- You want to create and connect inboxes by API, including advanced SMTP and IMAP
- You want a Postman collection and interactive reference to start from
- You want to move an inbox between Basic, Pro and Max by API
- You want to pull placement metrics per inbox into your own reports
Questions
Which Warmerly plan has API access?
Agency, at $179 a month. Free, Starter and Growth get a 403, though the MCP server works on every plan.
What is Warmup Inbox's API rate limit?
120 requests a minute, with the key sent in an x-api-key header. It includes a Postman collection with Node.js and Python snippets.
Does Warmerly have webhooks?
Yes, 16 mailbox health events, on the Agency plan only. Warmup Inbox does not mention webhooks.
How many API keys can I have on Warmerly?
Up to 10 active keys per user, with 60 requests a minute by default and 120 at most.
Sources
- Warmup Inbox API access
- Warmup Inbox pricing
- Warmup Inbox compared with Instantly (its own page)
- Warmup Inbox help centre, reply rate
- Warmerly API documentation
Warmup Inbox pages were read on 21 October 2026. Plans and wording change, so check the vendor's own page before you decide. Warmerly details come from the product as it runs today.
More features
- All features
- Starting price (per month)
- Cost at 5 and 25 mailboxes
- Free plan or trial
- What each tier adds
- Warm-up volume per mailbox
- Warmup network size
- Spam rescue
- Languages, templates and ESP targeting
- SPF, DKIM, DMARC and blocklists
- Placement test
- Supported mailboxes and sign-in
- Campaign sending
- Agency and client workspaces
- Data, support and terms
See it on your own mailbox.
Connect a mailbox. Warmerly runs alongside whatever you send from now, so you can compare before you move anything.
Free plan, no card. Paid plans: 7-day trial, first charge on day 8.