Hosted vs self-hosted, the real tradeoff
The choice is usually framed as cost. It is not. It is a trade of operational burden against an observer in your routing path, and the money is a distant third consideration.
The three axes that actually decide it
1 · Who observes your routing metadata. A hosted mediator's operator sees who connects, when, how often, and how large the envelopes are, structurally, not by policy (what a mediator can and cannot see). Self-hosting does not delete that observer; it makes you the observer. If that is unacceptable to a counterparty, hosted is disqualified before cost enters.
2 · Who is on call. A mediator is stateful. Queues grow, certificates expire, versions drift, and the failure mode is silent, messages that never arrive, surfacing days later as somebody else's bug. Self-hosting means owning that, permanently, for as long as the system runs.
3 · Who carries continuity risk. Hosted means depending on an operator's survival. Self-hosted on an Apache 2.0 project means the code outlives any vendor; see vs the OWF mediator.
Where money enters, and where it does not
The dominant cost of running a mediator is the operational floor, availability, on-call, upgrades, not throughput (what routing a message costs). That floor is roughly constant whether you serve ten agents or ten thousand.
Which produces the only genuinely economic conclusion available here: hosted wins on cost at low volume, self-hosted wins at high volume, and the crossover is set by your engineering time, not by bandwidth. A team that already runs stateful services has a much lower marginal cost than one that does not.
We are not publishing where that crossover falls, because relay has no rate card and a crossover computed against a price we have not set would be fiction.
The privacy inversion worth knowing before you decide
Self-hosting improves confidentiality of routing metadata, nobody outside sees it.
It usually worsens herd privacy, because a mediator serving one organisation has an anonymity set of one organisation, and every message through it is yours by definition. See herd privacy.
Both statements are true at once, and which matters depends on whether your adversary is the operator or an observer trying to single you out. Most "self-hosting is more private" instincts only consider the first.
A decision procedure
- Can a third party see your routing metadata? No → self-host. Stop.
- Is there a named owner for the service, with on-call? No → hosted.
- Is this production, needing support and an SLA? Yes → not us; consider a commercially supported mediator or self-host with a support contract, vs Indicio.
- Otherwise → hosted is the cheaper trade, and the burden you avoid is the actual product.