Aux0 vs building it yourself
Prototyping one mailbox is a weekend, and we do not pretend otherwise. What costs a year is sync that survives a reconnect, threading on servers that expose no thread id, quota pacing and the maintenance that never ends — and none of it is visible when you start.
- First working prototypeAux0About fifteen minutesbuilding it yourselfA weekend
- Production-ready, three providersAux0Days, most of it deciding how your product presents channelsbuilding it yourselfRoughly six months
- Incremental syncAux0Included, with cursor recovery after a reconnectbuilding it yourselfYours to build, per provider, and to rebuild when it changes
- Rate limitsAux0Paced inside each provider's own windowsbuilding it yourselfDiscovered by hitting them, usually on a customer's account
- Realtime deliveryAux0One IP per account, pinned by countrybuilding it yourselfAn IDLE pool, a watchdog, a fallback poll and a reconnect policy
- Credential handlingAux0Hosted auth; they never reach your systemsbuilding it yourselfYours to hold, encrypt, rotate and keep out of your logs
Claims about building it yourself checked October 2026
The short answer
VerdictYour team can build this. That is not in question and anyone telling you otherwise is selling badly. The question is what the second version costs — the one that runs a hundred of your customers' accounts, in nine countries, without someone watching it. This page is that cost.
Feature by feature
CoverageWhat each of us can do
A filled mark means it works today. Where they lead, the mark is theirs.
Prototype one provider
Both quick. This is the part that misleads.
- Aux0
- Yes
- In-house
- Yes
Unified object model across providers
You will build one eventually. It takes three attempts.
- Aux0
- Yes
- In-house
- No
Per-account rate budgets inside provider windows
- Aux0
- Yes
- In-house
- No
Connection pooling for IMAP IDLE
One socket per mailbox, held open, re-established on every drop.
- Aux0
- Yes
- In-house
- No
Threading where the server exposes no thread id
- Aux0
- Yes
- In-house
- No
Self-serve reconnect for end users
- Aux0
- Yes
- In-house
- No
Credentials never in your logs
Someone will log a request body. They always do.
- Aux0
- Yes
- In-house
- No
History backfill on connect
- Aux0
- Yes
- In-house
- No
Signed webhooks with retries and replay
- Aux0
- Yes
- In-house
- No
Keeps working when a provider changes a page
- Aux0
- Yes
- In-house
- No
Exactly the behaviour your product needs
The real argument for building.
- Aux0
- Partial
- In-house
- Yes
No vendor in your critical path
- Aux0
- No
- In-house
- Yes
| Aux0 | In-house | |
|---|---|---|
| Prototype one providerBoth quick. This is the part that misleads. | Yes | Yes |
| Unified object model across providersYou will build one eventually. It takes three attempts. | Yes | No |
| Per-account rate budgets inside provider windows | Yes | No |
| Connection pooling for IMAP IDLEOne socket per mailbox, held open, re-established on every drop. | Yes | No |
| Threading where the server exposes no thread id | Yes | No |
| Self-serve reconnect for end users | Yes | No |
| Credentials never in your logsSomeone will log a request body. They always do. | Yes | No |
| History backfill on connect | Yes | No |
| Signed webhooks with retries and replay | Yes | No |
| Keeps working when a provider changes a page | Yes | No |
| Exactly the behaviour your product needsThe real argument for building. | Partial | Yes |
| No vendor in your critical path | No | Yes |
Row by row
7 of 10 rows to Aux0First working prototype
Aux0Aux0
About fifteen minutes
building it yourself
A weekend
Production-ready, three providers
Aux0Aux0
Days, most of it deciding how your product presents channels
building it yourself
Roughly six months
Incremental sync
Aux0Aux0
Included, with cursor recovery after a reconnect
building it yourself
Yours to build, per provider, and to rebuild when it changes
Rate limits
Aux0Aux0
Paced inside each provider's own windows
building it yourself
Discovered by hitting them, usually on a customer's account
Realtime delivery
Aux0Aux0
One IP per account, pinned by country
building it yourself
An IDLE pool, a watchdog, a fallback poll and a reconnect policy
Credential handling
Aux0Aux0
Hosted auth; they never reach your systems
building it yourself
Yours to hold, encrypt, rotate and keep out of your logs
Ongoing maintenance
Aux0Aux0
Ours
building it yourself
About half a person, permanently
Fit to your product
themAux0
Our API surface, which may not match your model exactly
building it yourself
Exactly what you need, shaped how you want it
The strongest honest argument for building.
Dependency
themAux0
A vendor in the path of a core feature
building it yourself
Nobody between you and the provider
Unit cost at very large scale
themAux0
$5 per account per month at the top published tier
building it yourself
Can be lower once the engineering is already sunk
True above a few hundred accounts, if you already paid the build cost.
Which to pick
DecisionPick Aux0 if
- Channel integration is a feature of your product, not your product
- You need more than one provider, where the second does not reuse the first
- Nobody on the team wants to own IMAP sync state and token refresh in a year
- You would rather ship the feature this month than the infrastructure this half
- Your security review would rather you never held a user credential
Pick building it yourself if
- Channel infrastructure is the product you are actually selling
- You need one provider, one use case, and have someone to own it
- You are at several hundred accounts and the unit economics have flipped
- No vendor may sit in the path of this feature, for policy reasons
Not sure which side you are on? Tell us your case and we will say which of us fits it.
Where building it yourself is ahead
Their caseIt fits exactly, and nobody is in your path
An in-house integration matches your model precisely and adds no vendor to a core feature. If channel infrastructure is your actual product rather than a feature of it, build it — the control is worth the cost.
At very large scale the unit cost can be lower
Once the engineering is sunk, running several hundred accounts in-house can beat per-account pricing. That is a real calculation and it starts to favour building somewhere in the high hundreds.
Questions
FAQHow long does it really take to build mail sync in-house?
A working prototype against one mailbox takes a weekend. A version that runs your customers' accounts in production — incremental sync that survives a reconnect, OAuth token refresh, folder and label mapping, per-account quota pacing, a credential-safe auth flow and history backfill — is roughly six months of one engineer, and then about half a person permanently, because providers keep changing.
What do people underestimate most?
Three things, in order: that IMAP gives you a UID validity marker which invalidates your whole cursor without warning, so a naive sync silently re-downloads a mailbox; that Gmail labels and IMAP folders are not the same shape and a mapping that loses one is a bug a customer reports months later; and that a send which would exceed a provider's quota must be held, never returned as an error, because a caller that gets an error retries, and retrying is what gets the account rate-limited.
When is building genuinely the right call?
When the integration is the product rather than a feature of it, when you need one provider and have an owner for it, or when you are at several hundred accounts and the per-account price has stopped making sense against engineering you have already paid for.