PatternsMarkdown
Patterns help recover short, structured alphanumeric tokens — order codes, reference numbers, licence plates — that are easy to mishear when spoken letter-by-letter and digit-by-digit. When you know the shape of a token that may appear in the audio, describe it with a subset of regular-expression syntax and the transcription is corrected to fit.
Patterns are available on the Realtime, Prerecorded, and Turns APIs.
Using Patterns
Pass the patterns query parameter as a comma-separated list of patterns. Each one describes a single token to recover.
?patterns=AMZ[0-9]{6}
?patterns=[A-Z]{2}[0-9]{2} [A-Z]{3}
?patterns=(INV)?[0-9]{4,5}
?patterns=AMZ[0-9]{6},ORD[0-9]{5}
Patterns use a subset of regular-expression syntax:
| Syntax | Meaning | Example |
|---|---|---|
[0-9] |
a digit | [0-9]{6} |
[A-Z] |
a letter | [A-Z]{3} |
{n} |
repeat the preceding class exactly n times |
[0-9]{6} |
{m,n} |
repeat the preceding class m to n times |
[0-9]{4,6} |
(...)? |
an optional group — matched only when spoken | (INV)?[0-9]{5} |
AMZ |
literal letters/digits, e.g. a fixed prefix | AMZ[0-9]{6} |
- |
a separator | [A-Z]{2} [0-9]{3} |
Optional groups and ranges are resolved against the audio: an optional prefix is added only when it is actually spoken, and a {m,n} range adopts the spoken length. The more specific the pattern, the better — a fixed prefix or known structure (AMZ[0-9]{6}) is recovered more reliably than an open one.
A pattern matches tokens of at most 32 characters once fully expanded (the prefix and any digits or letters combined); a longer range or repeat is clamped to this limit. This is well above the length of typical order codes and reference numbers.
Examples
| Token type | Example value | Pattern |
|---|---|---|
| Order code | AMZ374019 |
AMZ[0-9]{6} |
| Reference number | 4429105538 |
[0-9]{10} |
| Licence plate | RU77 TVG |
[A-Z]{2}[0-9]{2} [A-Z]{3} |
| Invoice (optional prefix) | INV4821 or 4821 |
(INV)?[0-9]{4} |
| Variable-length code | AMZ3740 … AMZ374019 |
AMZ[0-9]{4,6} |
Only set patterns you expect
Patterns improve accuracy on audio that contains the token, but can degrade transcription of audio that does not. Set patterns only when the expected token is likely present in the request — don't apply them globally.
See the API reference for Realtime, Prerecorded, and Turns.