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Alternatives

Plunk alternative for AI agents: AgentiSend compared (2026)

Is AgentiSend a Plunk alternative?

Yes, for transactional email an agent sends through an API. A Free plan that does not expire: 1,000 emails a month, 100 a day, 3 domains, no card. Then plans from $9 a month (Starter, 30,000 emails). No plan daily cap; delivery paced per inbox provider. Or 20% off paid yearly. It is not a replacement for a product that is ahead on the rows marked in the other column.

Pick Plunk when you want $0.001 per email, inbound mail, a self-hosted install, or a local MCP server that asks before a multi-recipient send; pick AgentiSend when you want a per-key budget, signed webhooks with replay, and a hosted MCP with the same limits as the API. The figures below are from Plunk pages fetched on 28 September 2026 and from this product's pricing table and published API.

What mattersAgentiSendPlunk
A spending limit per keyEvery key is created with a send budget. The send path refuses with agent_budget_exceeded when it is spent, and a key cannot raise its own. The plan inclusion is a second ceiling (plan_limit_reached).Caps are per project and per category, not per key. Crossing one returns 402 with error code BILLING_LIMIT_EXCEEDED. A per-key send budget is not on the billing page.
What a refusal tells youEvery refused request carries code, message, fix (the call that repairs it), docs_url and retryable.The billing page names 402 and BILLING_LIMIT_EXCEEDED when a cap is hit. A fix field naming the next call is not on that page.
A retry never sends twiceIdempotency-Key is accepted on every endpoint that changes something and remembered for 7 days.An idempotency key is not documented on the billing page or the MCP guide.
How long the log keeps a message7 days on Free, 30 on Starter, 90 on Pro, 180 on Scale. It is part of the plan and there is no add-on to buy.A retention period is not stated on the pricing page, the billing page or the MCP guide.

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