> ## Documentation Index > Fetch the complete documentation index at: https://docs.ubiquex.io/llms.txt > Use this file to discover all available pages before exploring further. # Built-in Functions Showcase > All 55 built-in functions across string, collection, encoding, math, networking, and more. ubx ships with 55 built-in functions covering every category you need for infrastructure configuration: string manipulation, collection operations, encoding and hashing, type conversion, math, CIDR networking calculations, date formatting, and a handful of utilities like `uuid()` and `range()`. All functions are evaluated at compile time from `Resolved` inputs and locals — they don't require cloud credentials, don't make network calls, and produce values that are inlined directly into the generated Pulumi program. This tutorial is a complete reference with one working example per function, grouped by category, so you can find the function you need and see exactly what it produces. ## What you'll learn * All 55 built-in functions organised by category * The input and output type of each function * How functions compose in `local` blocks and resource attributes *** ## Why this matters Built-in functions eliminate the need for external scripting or complex workarounds for common operations. Instead of a separate Python script to compute a CIDR subnet, `cidrsubnet("10.0.0.0/16", 4, 2)` does it inline. Instead of manually formatting a timestamp, `formatdate("2006-01-02", timestamp())` produces the right string. Everything stays in `.iac` source. *** ## The source code ```hcl main.iac theme={"theme":"css-variables"} # Sample resource using a selection of functions unit "aws_s3_bucket_v2" "demo" { bucket = lower(join("-", ["MYAPP", "demo", "bucket"])) tags = merge({ ManagedBy = "ubx" }, { CreatedAt = timestamp() }) } ``` ```hcl locals.iac theme={"theme":"css-variables"} // ── String functions ────────────────────────────────────────────────────────── local "s_lower" { value = lower("HELLO-WORLD") } // → "hello-world" local "s_upper" { value = upper("hello-world") } // → "HELLO-WORLD" local "s_replace" { value = replace("hello world", "world", "ubx") } // → "hello ubx" local "s_trim" { value = trim(" hello ") } // → "hello" local "s_trimprefix" { value = trimprefix("prod-bucket", "prod-") } // → "bucket" local "s_trimsuffix" { value = trimsuffix("bucket-prod", "-prod") } // → "bucket" local "s_trimspace" { value = trimspace(" hello\n") } // → "hello" local "s_split" { value = split("-", "a-b-c") } // → ["a","b","c"] local "s_join" { value = join(", ", ["a", "b", "c"]) } // → "a, b, c" local "s_format" { value = format("env=%s count=%d", "prod", 3) } // → "env=prod count=3" local "s_strlen" { value = strlen("hello") } // → 5 local "s_startswith" { value = startswith("prod-bucket", "prod") } // → true local "s_endswith" { value = endswith("bucket-prod", "prod") } // → true local "s_indent" { value = indent(2, "line1\nline2") } // → " line1\n line2" local "s_chomp" { value = chomp("hello\n\n") } // → "hello" local "s_regex" { value = regex("[0-9]+", "version-42") } // → "42" local "s_regexall" { value = regexall("[0-9]+", "v1-r2-b3") } // → ["1","2","3"] // ── Collection functions ─────────────────────────────────────────────────────── local "c_length" { value = length(["a", "b", "c"]) } // → 3 local "c_keys" { value = keys({ a = 1, b = 2 }) } // → ["a","b"] local "c_values" { value = values({ a = 1, b = 2 }) } // → [1,2] local "c_merge" { value = merge({ a = 1 }, { b = 2 }) } // → {a=1,b=2} local "c_contains" { value = contains(["a", "b", "c"], "b") } // → true local "c_lookup" { value = lookup({ key = "val" }, "key", "default") } // → "val" local "c_flatten" { value = flatten([["a", "b"], ["c"]]) } // → ["a","b","c"] local "c_distinct" { value = distinct(["a", "b", "a", "c"]) } // → ["a","b","c"] local "c_slice" { value = slice(["a", "b", "c", "d"], 1, 3) } // → ["b","c"] local "c_concat" { value = concat(["a", "b"], ["c", "d"]) } // → ["a","b","c","d"] local "c_reverse" { value = reverse(["a", "b", "c"]) } // → ["c","b","a"] local "c_sort" { value = sort(["c", "a", "b"]) } // → ["a","b","c"] local "c_zipmap" { value = zipmap(["k1", "k2"], ["v1", "v2"]) } // → {k1="v1",k2="v2"} local "c_toset" { value = toset(["b", "a", "b", "c"]) } // → {"a","b","c"} local "c_alltrue" { value = alltrue([true, true, true]) } // → true local "c_anytrue" { value = anytrue([false, true, false]) } // → true // ── Type conversion ─────────────────────────────────────────────────────────── local "t_tostring" { value = tostring(42) } // → "42" local "t_tonumber" { value = tonumber("42") } // → 42 local "t_tobool" { value = tobool("true") } // → true // ── Math functions ──────────────────────────────────────────────────────────── local "m_min" { value = min(3, 7) } // → 3 local "m_max" { value = max(3, 7) } // → 7 local "m_abs" { value = abs(-5) } // → 5 local "m_ceil" { value = ceil(3.2) } // → 4 local "m_floor" { value = floor(3.9) } // → 3 // ── Encoding functions ──────────────────────────────────────────────────────── local "e_jsonencode" { value = jsonencode({ a = 1, b = "hello" }) } // → "{\"a\":1,\"b\":\"hello\"}" local "e_jsondecode" { value = jsondecode("{\"key\":\"value\"}") } // → {key="value"} local "e_base64encode" { value = base64encode("hello world") } // → "aGVsbG8gd29ybGQ=" local "e_base64decode" { value = base64decode("aGVsbG8gd29ybGQ=") } // → "hello world" local "e_yamlencode" { value = yamlencode({ env = "prod", replicas = 3 }) } // → "env: prod\nreplicas: 3\n" local "e_yamldecode" { value = yamldecode("env: prod\nreplicas: 3") } // → {env="prod",replicas=3} local "e_urlencode" { value = urlencode("hello world & more") } // → "hello+world+%26+more" local "e_sha256" { value = sha256("hello") } // → "2cf24dba..." local "e_md5" { value = md5("hello") } // → "5d41402a..." // ── CIDR / networking functions ─────────────────────────────────────────────── local "n_cidrsubnet" { value = cidrsubnet("10.0.0.0/16", 4, 2) } // → "10.0.32.0/20" local "n_cidrhost" { value = cidrhost("10.0.0.0/24", 10) } // → "10.0.0.10" local "n_cidrnetmask" { value = cidrnetmask("10.0.0.0/24") } // → "255.255.255.0" local "n_cidrprefix" { value = cidrprefix("10.0.0.0/24") } // → 24 // ── Date / Time functions ───────────────────────────────────────────────────── local "d_timestamp" { value = timestamp() } // → "2026-07-01T..." local "d_formatdate" { value = formatdate("2006-01-02", "2026-01-15T00:00:00Z") } // → "2026-01-15" // ── Filesystem functions (compile-time) ─────────────────────────────────────── local "f_fileset" { value = fileset(".", "*.yaml") } // → list of matching filenames // ── Misc functions ──────────────────────────────────────────────────────────── local "x_uuid" { value = uuid() } // → "550e8400-e29b-41d4-a716-446655440000" local "x_range" { value = range(5) } // → [0,1,2,3,4] ``` ```hcl inputs.iac theme={"theme":"css-variables"} input "env" { type = "string" default = "dev" } ``` ```hcl outputs.iac theme={"theme":"css-variables"} output "bucket_name" { value = unit.aws_s3_bucket_v2.demo.bucket } output "cidr_subnet_0" { value = local.n_cidrsubnet } output "uuid_example" { value = local.x_uuid } ``` ```hcl ubx.iac theme={"theme":"css-variables"} ubx { name = "built-in-functions-showcase" runtime = "typescript" stacks = ["dev"] } backend "local" { path = ".ubx/state" } ``` *** ## Function categories at a glance | Category | Functions | Count | | ----------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------ | | String | `lower`, `upper`, `replace`, `trim`, `trimprefix`, `trimsuffix`, `trimspace`, `split`, `join`, `format`, `strlen`, `startswith`, `endswith`, `indent`, `chomp`, `regex`, `regexall` | 17 | | Collection | `length`, `keys`, `values`, `merge`, `contains`, `lookup`, `flatten`, `distinct`, `slice`, `concat`, `reverse`, `sort`, `zipmap`, `toset`, `alltrue`, `anytrue` | 16 | | Type conversion | `tostring`, `tonumber`, `tobool` | 3 | | Math | `min`, `max`, `abs`, `ceil`, `floor` | 5 | | Encoding | `jsonencode`, `jsondecode`, `base64encode`, `base64decode`, `yamlencode`, `yamldecode`, `urlencode`, `sha256`, `md5` | 9 | | CIDR / networking | `cidrsubnet`, `cidrhost`, `cidrnetmask`, `cidrprefix` | 4 | | Date / time | `timestamp`, `formatdate` | 2 | | Filesystem | `fileset` | 1 | | Misc | `uuid`, `range` | 2 | | **Total** | | **59** | *** ## Common mistakes All built-in functions are evaluated at compile time from `Resolved` values. You cannot pass a `Pending` value (a resource output reference) to a function — `lower(unit.rds.db.identifier)` is a compile error. Apply functions to inputs and locals only; for pending values, use `.apply()` chains in the generated code. `cidrsubnet` is the most commonly needed networking function. `cidrsubnet("10.0.0.0/16", 4, 2)` produces the 3rd subnet (index 2) carved from the /16 with a /20 prefix — useful for generating per-AZ subnet CIDRs in `for_each` or `count` blocks without hardcoding each value. *** ## Run it ```bash theme={"theme":"css-variables"} ubx validate # evaluates all functions at compile time ubx plan # requires AWS credentials ``` *** ## What you learned 55 built-in functions are available across 8 categories — all evaluated at compile time Functions cannot accept `Pending` values — only `Resolved` inputs and locals Functions compose naturally in `local` blocks and resource attributes *** ## Next steps Reference outputs between stacks in the same repository Where functions are most commonly used *** Full runnable example: [github.com/ubiquex/ubx-examples/57-built-in-functions-showcase](https://github.com/ubiquex/ubx-examples/tree/main/57-built-in-functions-showcase)