How to get your Postmark API usage, balance and spend programmatically

What the Postmark API exposes

No billing API, so measure from your side

Argus counts sends from the SDK and applies Postmark's tier: a shared 10,000 emails a month on paid plans, then per-1,000 overage.

Credential. A Postmark Server API token, sent as X-Postmark-Server-Token. Argus validates it with GET /server.

Gotchas

• Tokens are per server, so one token sees one server's traffic.
• Overage on paid tiers is billed on the next cycle. The free developer tier hard-stops at 100 a month.

How Postmark charges

Feature tiers over a shared 10,000-email/month base, then metered per-1,000 overage. Free dev tier hard-stops at 100/mo.

Free allowance. 100 a month. Dev tier, no overage.

At zero. 422. Paid tiers meter overage past 10k (billed next cycle); Free hard-stops at 100/mo.

Or let Argus track it

Paste the key once. Argus keeps the ledger, and your coding agent reads it through the MCP server.

• With the SDK, counts each call and every 429 against the plan's allowance, since there's no meter to read.
• Emails you on low balance, days to zero, a spend spike, or projected overage.
• Hands all of it to your coding agent over MCP, so it can ask what a run cost or how much runway is left without leaving the editor.

> what has postmark cost today, and how long until it runs out?

get_overview       → postmark: mtd spend, burn per day, days to zero
get_request_costs  { "provider": "postmark", "limit": 25 }
get_advisories     → credits_low, spend_spike, rate_limit_low …

Questions

Does Postmark have an API for its balance?

Postmark exposes no spend, remaining quota or plan tier over the API. The Stats API (GET /stats/outbound/sends) gives per-day sent counts only.

Can I get Postmark spend per day from the API?

No. Count calls and price them yourself, or let the Argus SDK do it.

What happens when Postmark credits run out?

Requests fail with HTTP 422. Paid tiers meter overage past 10k (billed next cycle); Free hard-stops at 100/mo.

What key does Argus need for Postmark?

A Postmark Server API token, sent as X-Postmark-Server-Token. Argus validates it with GET /server.

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