API & integrations
The eSignature API is sold as its own product with separate envelope caps and per-call pricing — your $40 seat doesn't unlock it.
What people actually say
✕Starter API access runs around $600 a year with a 40-envelope monthly limit, Advanced jumps to roughly $5,760 for bulk send and webhooks, and Enterprise customisations can exceed $10,000 a year plus per-envelope API call charges.
Source: esign.ai, API and developer costs ↗✕Web Forms and the eSignature API are sold as standalone products separate from the user-facing eSignature plans, so adding programmatic signing means a new contract on top of seats.
Source: PandaDoc, DocuSign product modularisation ↗✕API users still hit envelope allowances and overage charges — the per-call model means a busy integration can blow the budget without anyone in legal noticing.
Source: esign.ai, API overage exposure ↗
Your signing API is just your Next.js app — REST and webhooks for the same envelope store the UI talks to, no separate SKU. Embed signing into your product with iframe or redirect, send envelopes from a cron job, fire webhooks on completion. No call meter, no Web Forms upsell.