Limits
Sess rejects anything over a limit with an explicit error; it never truncates or guesses. Limit changes apply prospectively and are announced in the changelog.
On this page
Requests and content
| What | Limit | Error |
|---|---|---|
| Request body | 256 KiB | 413 PAYLOAD_TOO_LARGE |
| Page content (UTF-8 bytes of the canonical Surface) | 128 KiB | 413 PAYLOAD_TOO_LARGE |
| Title | 1 to 200 characters, not only spaces | 400 INVALID_SCHEMA |
| Description | Up to 4,000 characters | 400 INVALID_SCHEMA |
| Display Sessions: data | At least one top-level key; each value a string, number, boolean or null, a record of such values, or a table of 1 to 100 such records with the same keys | 400 INVALID_SCHEMA |
| Human link lifetime: Sessions created with your API key | 7 days after the Session is created (developer account, free workspace) Draft — lands with P1 increment 2 | Generic "not found" page |
| Session content kept: Sessions created with your API key | 7 days after the Session is completed or its link expires, whichever comes first (developer account, free workspace) Draft — lands with P1 increment 2. See Retention. | 404 SESSION_NOT_FOUND |
| Human link lifetime: the operator key only (held by the Sess team, never issued to developers) | 30 days after the Session is created | Generic "not found" page |
| Session content kept: the operator key only | 30 days after the Session is completed or its link expires, whichever comes first | 404 SESSION_NOT_FOUND |
Files, images, external media and remote content are not supported. The exact schemas are in the API reference.
Interactive Sessions
| What | Limit |
|---|---|
| Components (heading, text, record, field) | 1 to 100 |
| Input fields | Up to 50 |
| Actions | 1 to 5 |
| Choices in one list (enum values) | Up to 100 |
| Key/value pairs in one record | Up to 50 |
| Text component | Up to 4,000 characters |
| Text field | Up to 4,000 characters unless the field declares maxLength (at most 10,000) |
| Accepted responses | One per revision |
Unsupported components fail with 400 UNKNOWN_COMPONENT; unsupported schema keywords with 400 INVALID_SCHEMA.
A cap on accepted rounds per Session (initially 10). Draft — lands with P1 increment 2
Webhooks
| What | Limit |
|---|---|
| Endpoints | One per workspace: an https:// URL on port 443, up to 2,048 characters, no user info or fragment, resolving to a public address |
| Verification | Valid for 30 days; verify again to renew |
| Each attempt | 10-second timeout, no redirects followed, your response read up to 64 KiB |
| Retries | Up to 12 attempts within 24 hours; Retry-After honored up to 1 hour |
| Secret rotation | The previous secret keeps signing for 24 hours |
No-signup trial
| What | Limit |
|---|---|
| New trials | 3 per client per rolling 24 hours, and 200 overall per rolling 24 hours |
| Sessions in one trial | Up to 3 active at a time, and 10 created within the trial's 24-hour creation window |
| Answer window | 1 hour after the Session is created |
| Result retrieval | 24 hours after the answer window ends |
| Rounds | One answered revision per trial Session (publishing a next revision needs an API key) |
| Webhooks and outbound calls | None |
A "client" is identified by the network address the request comes from. People who share a network, such as an office, a VPN or a mobile carrier, may share the per-client allowance and see 429 RATE_LIMITED before they have started three trials themselves. The response carries a Retry-After header. These are preview settings and may be tightened if abused, without changing Sessions already created.
Plan limits
Draft — lands with P1 increment 2 Planned; not available on the current API.
| Plan | Active Sessions | Volume | Live lifetime | Webhooks |
|---|---|---|---|---|
| Free workspace | 25 (planned) | 500 resolved Sessions per month (planned) | Up to 7 days | Yes, verified endpoints |
| Paid pilot (planned) | 100 | 5,000 resolved Sessions per month | Up to 30 days | Yes, verified endpoints |
Every developer workspace is on the free workspace today. Its 7-day live lifetime and its retention (see Retention) are enforced for each Session; the active-Session cap and the monthly volume are planned and not yet enforced. The paid pilot is not available yet.
Once allowances are enforced, a new Session beyond an allowance is rejected with a clear error. Work already in progress, including accepted responses and their delivery, still finishes. Sess never charges an automatic overage.