# AgentMail vs Nylas Source: https://wraps.dev/versus/agentmail-vs-nylas Should your agent have an address of its own, or act from inside the user's existing mailbox? The two products answer that differently, and the answer decides your billing model, your launch date and your failure modes. This is not really a comparison of two APIs. It is a decision about whose mailbox the agent lives in, and the vendor follows from the answer. If the agent is a participant — a teammate with a name, an address and a signature — it wants a mailbox of its own. If the agent is an assistant acting for a specific person, it has to be inside that person's mailbox, seeing what they see and sending as them. Those are different products because they are different problems, and picking the wrong one is not a preference mistake, it is a rewrite. ## At a glance |   | AgentMail | Nylas | | --- | --- | --- | | What it is | Hosted inbox API built specifically for AI agents | Unified API for real Gmail and Outlook mailboxes | | Published pricing | Free at 3 inboxes, 3,000 emails/mo and 100/day. Developer $20/mo for 10 inboxes and 10,000 emails/mo. Startup $200/mo for 150 inboxes and 15,000 emails/day, with monthly volume quoted. Enterprise is custom. Overage rates are not published. | Free sandbox with 5 connected accounts. Full Platform $15/mo base including 5 connected accounts and 20 agent accounts, then $2.00 per extra account and $0.20 per extra agent account. Calendar-only $10/mo. Enterprise custom. | | Best for | Agent builders who want an inbox from a single API call and no email infrastructure to run. | Agents that must work inside a person's existing mailbox rather than from an address of their own. | | Watch out for | Plans meter inboxes before volume — Developer caps at 10 — so a fleet outgrows the tier long before the send limit. Mail sits in their storage, and no compliance certification is published. | Billing follows connected accounts, and you inherit Google and Microsoft OAuth review — a security assessment on their schedule, not yours, and a common cause of slipped launch dates. | Prices are each vendor's published list prices, verified August 2026. Check the vendor's own page before you sign anything. ## Where they actually differ ### Whose name is on the message AgentMail The agent's. It has its own address, ideally on your own domain, and the recipient sees a correspondent that is visibly not a person. That is honest, it keeps the audit trail clean, and it works when there is no specific human the agent is acting for — a support triage bot, a procurement agent, a scheduler that talks to counterparties on behalf of a company rather than a person. Nylas The user's. Nylas connects to a real Gmail or Outlook mailbox and acts inside it, so replies land in the thread the human is already reading and outgoing mail appears in their sent folder. For an assistant that is exactly right, and it means everything the agent does is visible to the person it works for, in the tool they already have open. ### The approval that decides your launch date AgentMail There is none from a mailbox provider, because you are not touching one. You verify a domain, authenticate it and start sending, which is a process measured in hours and controlled entirely by you. This is the single largest practical advantage of the agent-owned-inbox model and it is rarely the one that gets talked about. Nylas Google and Microsoft both gate the scopes that read a user's mail. Reaching general availability with restricted scopes means a verification process that includes an independent security assessment, conducted on the assessor's schedule and repeated annually. Teams routinely discover this after building the integration, and it is the most common reason an assistant product ships to a handful of test users for a very long time. ### What the meter counts AgentMail Mailboxes and volume. Your cost scales with how many agents exist and how much they send, which is a curve you control directly: consolidate agents and the bill falls. The lower tiers cap mailbox count fairly aggressively, so a fleet architecture needs checking against the plan before you commit to one inbox per task. Nylas Connected accounts. Every user who links their mailbox is a line on the bill whether the agent did anything for them this month or not, which makes the economics a function of activation rather than usage. A free tier full of connected-but-idle accounts is a real cost, and it pushes you toward gating the connection behind a paid plan. ### History the agent can see AgentMail Nothing, until the agent has been talking for a while. A new agent inbox starts empty, which is clean and also means the agent has no idea what was agreed with this customer last quarter unless you feed it from somewhere else. Context has to come from your own systems, which you probably want anyway. Nylas Everything the user has. That is the feature: an assistant can search years of correspondence, understand a thread before replying and pick up context the user never explicitly gave it. It is also the reason the security review exists, and the reason your data-handling story has to be considerably more careful than it would be for an agent with its own address. ### Beyond email AgentMail Email is the scope. If the agent needs to schedule something it does that through whatever calendar integration you build separately, which is more moving parts and also a clean separation you may prefer. Nylas Calendar and contacts arrive on the same connection, which is why scheduling assistants gravitate here. One OAuth grant gets you the mailbox, the availability and the address book, and for an agent whose job is arranging things between people that consolidation is most of the value. ### Rate limits you did not set AgentMail The provider's, which are commercial limits attached to your plan and negotiable in the ordinary way. If an agent needs to process a burst, that is a conversation with a vendor who wants your business. Nylas Google's and Microsoft's, applied per connected account, and not negotiable by you or by Nylas. A backfill of a large mailbox is throttled by the mailbox provider, and a user with an enormous archive is slow to onboard for reasons no amount of engineering on your side fixes. ### How the integration breaks AgentMail Ordinarily. An API call fails, a domain's DNS is misconfigured, a message bounces. Everything that goes wrong is inside a system you or your vendor operates, which means it is diagnosable and fixable on your own timeline. Nylas Sideways. A user changes their password, an administrator revokes application access for the whole tenant, a token expires, a security policy changes, or the account is a shared mailbox with different permissions than the personal one you tested against. Each of these silently stops the agent for one user, and your product needs a reconnection flow and a monitoring story for it on day one. ### Onboarding friction for the person being helped AgentMail None worth naming. The agent has an address because you gave it one, and the user does not have to authorise anything, install anything or understand anything. For a product where activation rate is the metric that matters, removing an authorisation screen from the first-run flow is worth more than most features you could ship instead. Nylas A consent screen listing the access you are requesting, shown to somebody who has been trained to be suspicious of exactly that screen. In an organisation it may be blocked outright by an administrator policy, which turns activation into an internal approval request the user has to champion on your behalf. That is a real and measurable drop-off, and it is structural rather than something better copy fixes. ### What a security reviewer asks about each AgentMail Where the mail is stored, who at the vendor can read it, and what certification backs that. Those are answerable questions, and with a young vendor the honest answer may be thinner than an enterprise buyer wants. The surface is at least small: one vendor, one class of data. Nylas Everything above, plus why your application needs read access to an employee's entire mailbox, what you do with it, how long you keep it and who else sees it. That conversation is harder, it involves the customer's own administrators, and it is the reason mailbox-connected assistants sell more easily to individuals than to enterprises. ## Pros and cons, side by side ### AgentMail Strengths - Nothing outside your own company gates the launch, so the gap between deciding to build this and sending the first message is measured in hours. - The person being helped authorises nothing, installs nothing and understands nothing, which removes an entire screen from the flow where activation is decided. - Failures happen inside systems you or your supplier operate, so a diagnosis is a matter of reading logs rather than guessing at somebody else's policy change. - Cost tracks how many agents exist and how much they send, which is a curve you can shorten by consolidating agents rather than by persuading users. Trade-offs - The agent begins knowing nothing, so every piece of context it needs about a customer has to be fed from a system you already maintain. - Scheduling anything means a separate calendar integration with its own authorisation, its own failure modes and its own place in your architecture. - A recipient can see they are corresponding with software, which is honest and is occasionally the opposite of what the buyer was hoping for. - A security reviewer gets a conversation rather than a certificate, because the supplier is young enough not to have one to hand over. ### Nylas Strengths - Years of the user's own correspondence are available to the assistant, which is the whole feature and is not something the other model can approximate. - The work appears in the user's own sent folder and threads, so trust is built by visibility rather than by a report the product generates about itself. - Calendar and contacts arrive on the same authorisation, which for an assistant whose job is arranging things between people is most of the value. - The assistant acts as the person it works for, so a reply lands in the conversation the counterparty is already reading rather than starting a new one. Trade-offs - Reaching general availability on the scopes that read a mailbox means an independent assessment on an assessor's calendar, repeated every year. - Every linked account is billed whether the agent did anything for that person this month, which makes the economics a function of activation rather than usage. - The rate limits belong to the mailbox provider, applied per account, and are negotiable by nobody — not by you and not by the supplier you are paying. - An administrator can revoke access for an entire organisation in one action, and the first you hear of it is a support ticket from a confused customer. ## Pick in thirty seconds ### Choose AgentMail if - The agent represents your company rather than a specific person, so there is no user mailbox it could plausibly live inside. - You want to ship this quarter and cannot absorb a third-party security assessment on somebody else's schedule. - Recipients should be able to see they are corresponding with an automated system, because that is the honest design. - Your economics work per agent rather than per connected user, and idle accounts should not appear on the bill. ### Choose Nylas if - The agent assists one named person and has to see and act on the mail that person already receives. - Calendar and contacts are part of the job, and consolidating them into one authorisation is a real simplification. - Users need to see the agent's work in their own sent folder, because that visibility is what makes them trust it. - You are prepared to fund and schedule the verification work that reading a user's mailbox requires. ## What actually moves when you switch In roughly the order you would do it. The expensive parts of an email migration are never the send call. 1. Start the verification paperwork on the day you choose the architecture rather than the day the feature works. The engineering finishes long before the approval does, and most of the elapsed time is not a reviewer reading your form — it is an independent assessment booked against a third party's availability. Teams that build first and apply afterwards ship to a handful of test accounts for months. Teams that apply first find the paperwork has caught up by the time the code has, which is the same work in a different order and a materially different launch date. 2. Put the assessment on the budget as a recurring line rather than a one-off, and find out what it costs before anybody commits to the model. It is repeated annually, it involves somebody outside your company looking at how you handle the data, and it constrains what you can change afterwards without going round again. None of that is unreasonable for access to an employee's whole mailbox. It is simply a permanent overhead that has no equivalent on the other side of this page, and it should be visible in the comparison rather than discovered in month four. 3. Model the bill on linked accounts including the ones that never do anything, because that is the number you are charged for. A free tier full of people who connected their mailbox during onboarding and never returned is a real monthly cost with no matching revenue, and the usual response is to gate the connection behind a paid plan — which is a product decision with conversion consequences, made for billing reasons. Decide it deliberately now rather than reactively when the invoice arrives. 4. Write the reconnection flow before launch, because the integration does not fail loudly. A password change, an expiring token, an administrator tightening a policy, a multi-factor requirement, an account moving between tenants — each of these silently stops the agent for exactly one person, who then experiences your product as having quietly given up on them. You need detection, a clear message, a one-click path back, and an alert for the case where many accounts disconnect at once because something changed at the organisation rather than at the person. 5. Test against a shared mailbox and a delegated one, not only against a personal account you control. Permissions on a shared box differ, delegation behaves differently again, and an organisation's setup is routinely more complicated than the one you developed against. The failure shows up as an agent that works perfectly for the champion who bought your product and fails for the team they wanted to roll it out to, which is the single worst moment for it to appear. Find two customers with awkward configurations during the trial and make them part of the test matrix. 6. Treat the authorisation screen as a funnel step and measure it, because it is where the model costs you customers. Somebody who has been trained to be wary of exactly this screen is being asked to grant access to their whole mailbox, and in an organisation the request may be blocked outright by policy — turning your activation into an internal approval the user has to champion on your behalf. Find out what share of your target customers work somewhere that would block it, before rather than after the drop-off appears in the numbers. 7. Decide what you keep from a user's mailbox and for how long, and write it down in the words a reviewer will use. The answer is the security conversation, and a vague one turns a sale into a quarter of correspondence. Minimise deliberately: process in memory where you can, store only what the feature genuinely needs, put an expiry on it, and be able to say who at your company could read it and under what circumstances. This is cheap to design in and expensive to retrofit, because retrofitting means explaining what you used to do. 8. Plan the first synchronisation as a product problem rather than an engineering one. A large archive backfills at whatever rate the mailbox provider permits, which is not a rate you or your supplier can raise, so a user with a decade of mail waits — and waits during exactly the minutes when they are deciding whether your product works. Design the first-run experience around partial data: be useful on the recent mail immediately, show progress honestly, and do not let the agent appear to have no context when the truth is that it has not finished reading yet. ## Questions to ask before you sign Put these to a sales rep, or find the answer in the documentation before anyone quotes you a number. 1. Have we started the verification process, and does our launch date assume an assessor's calendar or our own? 2. What does the annual assessment cost, and is it on the budget as a recurring line rather than a one-off? 3. How many accounts would connect and then go idle, and are we charged for them? 4. What happens in our product when one user's token is revoked, and who finds out first — us or them? 5. Have we tested against a shared or delegated mailbox, or only against a personal account we own ourselves? 6. What share of our target customers work somewhere an administrator would block this authorisation outright? 7. What exactly do we retain from a user's mailbox, for how long, and who here could read it? ## Common questions ### Why can I not just ask users for an app password? Because that door is closing. Google removed less secure app access for most accounts, Microsoft has been disabling basic authentication across tenants, and administrators in any organisation with a security team block what remains. An integration built on stored credentials also fails the first serious security review you face, and it makes you responsible for holding a credential that unlocks far more than your feature needs. ### How long does Google verification actually take? Plan in months rather than weeks for restricted scopes, and note that most of the elapsed time is not Google reviewing your form — it is the independent security assessment, scheduled against a third party's availability and repeated annually. The practical advice is to start it the day you decide on the architecture rather than the day the feature is ready, because the engineering finishes long before the paperwork does. ### Can an agent send from a user's address without the user's mailbox? Only in the sense that you can put their name and address in the from header, and doing that without authorisation for the domain is exactly what authentication standards exist to stop. If the domain belongs to the user's employer and they are willing to authorise you, sending as them is legitimate and a matter of configuration. If it is a personal address at a large consumer provider, the answer is effectively no, and messages that attempt it land in spam. ### Which model is better for an inbound support agent? Usually its own address, because support mail already arrives at a company address rather than a person's, and because the agent needs to keep working when an individual employee is on holiday or leaves. The mailbox-connected model fits better when the agent is triaging one person's inbox for them, which is a different product even though the phrase support agent covers both. ### Can I combine the two? Yes, and mature products often do: an owned address for outbound campaigns and automated correspondence, plus optional mailbox connection for users who want the assistant to work inside their own inbox. The cost is two integrations, two failure modes and two compliance stories, so it is worth doing in sequence rather than at once — ship the one your core use case needs and add the other when customers actually ask. ### What does the independent security assessment actually involve? Somebody outside your company examining how your application handles the data it is asking for, against a published set of requirements, and producing a report the mailbox provider will accept. In practice that means answering a long questionnaire about your architecture, demonstrating that you encrypt what you store and limit who can reach it, showing that access is logged and that departing staff lose it, and evidencing that you have a process for handling a breach rather than an intention to have one. Some of it is a scan of your application; some of it is document review. The two things teams underestimate are that it is booked against the assessor's calendar rather than yours, and that it repeats annually — so the cost is not a launch expense but a standing one, and a significant change to how you handle mailbox data can mean going round again. None of this is unreasonable given what is being granted. It is simply a fixed overhead that does not exist at all if the agent has an address of its own, which is the comparison this page is really about. ### What should happen when a user's connection is revoked? Your product should notice within minutes, tell the person plainly, and offer one click that fixes it — and building all three before launch is much cheaper than adding them after the first confused support ticket. Revocation arrives in several disguises: a token that simply expires, a password change, an administrator withdrawing consent for the whole organisation, a security policy that newly requires something your grant does not have. From your side they look similar, which is a detection problem rather than a diagnosis one. Watch for authorisation failures per account, distinguish a transient error from a durable one so you do not nag somebody about a five-minute outage, and set a separate alert for many accounts failing at once, because that pattern means something changed at a company rather than at a person and needs a conversation with their administrator rather than an email to their staff. The message the user sees matters too: somebody who is told that the assistant has been disconnected and here is the button will reconnect, and somebody who simply notices it has gone quiet will assume the product does not work. ### How likely is an administrator to block us? Likely enough that it belongs in your market sizing rather than in your risk register. Any organisation with a security function restricts which third-party applications may request access to staff mailboxes, and the default posture in most of them is to allow nothing that has not been reviewed. That turns your signup into an internal approval request which your user has to champion, in a queue they do not control, against a reviewer whose incentive is to say no. Some of this is winnable — publishing your verification status, having documentation a reviewer can read, being on the list of applications that organisation has already approved — and some of it is structural. The practical step during evaluation is to find out where your target customers work and how those places handle this, because the answer varies enormously between a fifteen-person startup and a regulated enterprise. An assistant that sells beautifully to individuals and stalls entirely at organisations is a common and expensive outcome, and it is visible in advance if you ask. ### Why is the first synchronisation so slow, and can we speed it up? Because the mailbox provider is metering it, and no, not by engineering. Backfilling somebody's archive means pulling a great deal of data through an interface that applies per-account rate limits, and those limits belong to the provider rather than to the integration supplier you are paying — so throwing more workers at it produces throttling rather than throughput. A user with a decade of correspondence can be waiting a long time, and they are waiting during precisely the first session in which they decide whether your product is any good. The fix is a product one. Sync recent mail first and be genuinely useful on it within a minute; show the backfill as visible progress rather than a spinner; and make the agent's answers honest about what it has and has not read yet, because an assistant that confidently says it found nothing is worse than one that says it is still looking. Design the first run for the slowest reasonable case and the fast ones take care of themselves.