Documentation Index
Fetch the complete documentation index at: https://docs.ellomas.com/llms.txt
Use this file to discover all available pages before exploring further.
Templating and Functions
Replay uses Handlebars-style {{ var }} syntax for variable interpolation, plus 45 built-in functions for data transformation.
Variable Interpolation
Any string field in a step can reference state variables:
- name: dynamic-request
type: http
request:
url: /users/{{ user_id }}
headers:
Authorization: Bearer {{ token }}
body:
name: "{{ user_name }}"
email: "{{ user_email }}"
Nested Access
Access nested fields with dot notation:
name: "{{ config.http.base_url }}"
message: "Hello {{ user.profile.first_name }}"
Environment Variables
Environment variables are loaded into the global scope at startup. Access them directly:
config:
postgres:
dsn: postgres://{{ POSTGRES_USER }}:{{ POSTGRES_PASSWORD }}@localhost:5433/mydb
Built-in Functions
String Functions
| Function | Description | Example | Result |
|---|
upper | Convert to uppercase | {{upper "hello"}} | HELLO |
lower | Convert to lowercase | {{lower "HELLO"}} | hello |
upperFirst | Capitalize first letter | {{upperFirst "hello"}} | Hello |
lowerFirst | Lowercase first letter | {{lowerFirst "Hello"}} | hello |
trim | Trim whitespace | {{trim " hi "}} | hi |
replace | Replace all occurrences | {{replace "a-b-c" "-" "."}} | a.b.c |
contains | Check substring | {{contains "hello" "ell"}} | true |
startsWith | Check prefix | {{startsWith "hello" "he"}} | true |
endsWith | Check suffix | {{endsWith "hello" "lo"}} | true |
split | Split string | {{split "a,b,c" ","}} | ["a","b","c"] |
join | Join array | {{join (split "a,b" ",") "-"}} | a-b |
truncate | Truncate with ellipsis | {{truncate "hello world" 8}} | hello... |
padLeft | Pad left | {{padLeft "42" 5 "0"}} | 00042 |
padRight | Pad right | {{padRight "42" 5 "."}} | 42... |
repeat | Repeat string | {{repeat "ab" 3}} | ababab |
regexMatch | Regex test | {{regexMatch "^\\d+$" "123"}} | true |
regexFind | Regex find first | {{regexFind "\\d+" "abc123def"}} | 123 |
Math Functions
| Function | Description | Example | Result |
|---|
add | Addition | {{add 5 3}} | 8 |
sub | Subtraction | {{sub 10 4}} | 6 |
mul | Multiplication | {{mul 3 4}} | 12 |
div | Division | {{div 10 3}} | 3.333 |
mod | Modulo | {{mod 10 3}} | 1 |
min | Minimum | {{min 5 3}} | 3 |
max | Maximum | {{max 5 3}} | 5 |
round | Round | {{round 3.7}} | 4 |
abs | Absolute value | {{abs -5}} | 5 |
ceil | Ceiling | {{ceil 3.2}} | 4 |
floor | Floor | {{floor 3.8}} | 3 |
Date Functions
| Function | Description | Example | Result |
|---|
now | Current UTC time (RFC3339) | {{now}} | 2026-06-03T12:00:00Z |
nowUnix | Current Unix timestamp | {{nowUnix}} | 1759507200 |
addMinutes | Add minutes | {{addMinutes "2026-01-01T00:00:00Z" 30}} | 2026-01-01T00:30:00Z |
addHours | Add hours | {{addHours "2026-01-01T00:00:00Z" 2}} | 2026-01-01T02:00:00Z |
addDays | Add days | {{addDays "2026-01-01T00:00:00Z" 7}} | 2026-01-08T00:00:00Z |
formatDate | Format date | {{formatDate "2026-01-01T00:00:00Z" "2006-01-02"}} | 2026-01-01 |
parseDate | Parse date string | {{parseDate "2026-01-01" "2006-01-02"}} | 2026-01-01T00:00:00Z |
dateSub | Date difference (seconds) | {{dateSub "2026-01-02T00:00:00Z" "2026-01-01T00:00:00Z"}} | 86400 |
JSON Functions
| Function | Description |
|---|
jsonStringify | Convert value to JSON string |
jsonParse | Parse JSON string to value |
jsonPick | Extract nested value from object by path |
jsonKeys | Get object keys |
jsonValues | Get object values |
object | Build object from key-value pairs |
merge | Merge two objects |
Type Conversion Functions
| Function | Description |
|---|
toInt | Convert to integer |
toFloat | Convert to float |
toString | Convert to string |
len | Length of string, array, or object |
Combining Functions
Functions can be nested:
message: "{{ upper (trim user_name) }}"
message: "{{ add (toInt count) 1 }}"
message: "{{ join (split tags ",") ", " }}"
What’s Next?