Limits
The engine's and the SDKs' limits, from their code. The engine checks most of them when you sync, or when an event comes in.
IDs and names
| What | Limit |
|---|---|
| App ID, function ID | 1-64 characters: letters, digits, -, _, starting with a letter or digit |
Failure handler ID (<id>-failure) | also 64 characters, so onFailure needs a function ID of at most 56 |
| Event name | 1-256 characters; not starting with inngest/ |
Event id | up to 256 characters |
| Realtime channel | 1-256 characters: letters, digits, : _ - . |
| Realtime topic | 1-64 characters: letters, digits, _ - . |
Events
| What | Limit |
|---|---|
Events per request (flow.send, POST /e, step.sendEvent) | 100 |
| One event (all its fields, as JSON) | 1 MB |
| One request body | 10 MB |
| Events a second, per workspace | set by the plan; over it, 429 |
Functions and runs
| What | Limit |
|---|---|
| Steps per run | 1000 |
Retries per step (retries) | 0-20, default 4 |
One call to your app (timeouts.step) | default 5 minutes; kept between 1 second and 14 minutes |
A whole run (timeouts.finish) | no limit by default; at least 1 second |
| One step's result | 4 MB |
| The function's return value | 4 MB |
| Everything a run holds (events, step results, output) | 32 MB |
| Your app's answer to one call | 5 MB |
step.invoke data | 1 MB |
cancelOn entries per function | 5 |
A cancelOn with no timeout | listens up to 366 days |
waitForEvent look-back | events up to 1 hour before the wait |
| A run waiting for a down app | 7 days, then AppUnavailable |
step.sleep, step.sleepUntil | no limit; a time in the past ends at once. A cancelOn with no timeout still stops listening after 366 days, and time asleep counts toward timeouts.finish. |
An event ts in the future | no limit |
| Tags per function | 3; names up to 32 characters; a value over 256 characters is left out |
| Sync manifest | 1 MB |
| Expressions | 2048 characters, no regular expressions |
Flow control
| What | Limit |
|---|---|
| Concurrency limits per function | 2 |
Concurrency limit | 0 (no limit) to 100,000 |
Throttle and rate limit limit | 1 to 100,000 |
| Throttle, rate limit and debounce periods | 1 second to 7 days |
Batch size (maxSize) | 1 to 100 events |
Batch timeout | 1 second to 1 hour |
| Batch total | 4 MB |
| Priority | -600 to 600 seconds |
Keeping data
| What | How long |
|---|---|
| A sleeping or waiting run | while it is active: only ended runs are deleted |
| A completed or cancelled run | 3 days after it ends, unless kept |
| A failed run | 4 days after it ends, unless kept |
| Events (dashboard, event pages) | 4 days |
An event id or idempotency value is caught | while the first run is kept |
| A pending signing key from Add app that no app connects with | 7 days |
Finding runs
| What | Limit |
|---|---|
flow.runs.list page (limit) | 1 to 200, default 50 |
| Tag filters in one list | 3 |
| Runs cancelled by tag in one call | 500, oldest first; more says there are more, and next goes on from there |
How far list and counts lag the runs | a few seconds |
Ended runs in counts | only since since (see Keeping data) |
flow.runs.singleton and cancel by run ID or singleton key read the runs themselves, with no lag.
Realtime
| What | Limit |
|---|---|
| One publish (the whole body) | 64 KB |
publishMany | 1 to 100 messages; the body up to 1 MB; each message's data up to 64 KB |
| Channels on one token or socket | 1 to 100, with up to 8,000 characters of names in all |
See also Realtime.
Streams
| What | Limit |
|---|---|
| Stream ID | 1-256 characters: letters, digits, : _ . -; not ., .., token or connect |
| One item, as JSON | 64 KB |
| Items per append | 100 |
| Request body | 1 MB |
| Items per stream | 20,000 |
| Bytes per stream | 32 MB |
ttl (open) | 1 second to 7 days |
grace (close) | 0 to 7 days |
meta, as JSON | 4 KB |
| One snapshot page | 1000 items and about 4 MB (snapshot reads every page) |
| Readers (sockets) per stream | 1,000 |
| A reader token must connect within | 1 minute |
| A reader socket lasts | up to 1 hour; then the reader gets a new token and goes on |
The end item that close writes counts toward the limits, but is never refused for them.
Timing
| What | Time |
|---|---|
| A signed call's clock may be off by | 5 minutes |
| A revoked key stops working within | about 10 seconds |
| A sync reaches every engine machine within | about 10 seconds |
| The sync at boot checks again every | 5 minutes |
| Streamed answer heartbeat | 20 seconds |
| A concurrency slot of a crashed call is freed after | the step timeout plus 2 minutes |
| A realtime token must connect within | 1 minute |
| A realtime connection lasts | up to 1 hour |
| Browsers on one realtime channel | 1,000 |
| One realtime publish | 64 KB |
When a run's state is over 4 MB, the engine does not send it in each call: the SDK loads it from the engine, at FLOW_BASE_URL. If you run your own engine, set FLOW_BASE_URL in every app, even ones that never send events.