StringSpec

Search 791 lab-measured tennis strings by name, brand, material and gauge, sorted by a measurement or by price. Each result carries stiffness (lb/in), tension loss (%), energy return (%), spin potential, ball bite and string friction, each with its percentile in the database, plus the current retail price, a buy link and the StringSpec page. Returns at most 10 strings; narrow the filters rather than asking for more.

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string",
      "maxLength": 80,
      "description": "Words from the string's name, e.g. \"alu power\", \"hyper-g\", \"rpm blast\"."
    },
    "brand": {
      "type": "string",
      "maxLength": 60,
      "description": "Brand name, e.g. \"Babolat\", \"Luxilon\", \"Solinco\"."
    },
    "material": {
      "type": "string",
      "enum": [
        "Polyester",
        "Nylon",
        "Nylon/Polyester",
        "Gut",
        "Nylon/Polyurethane",
        "Nylon/Zyex",
        "Nylon/Polyolefin",
        "Polyolefin"
      ],
      "description": "Construction family. Polyester is the stiff spin-friendly monofilament; Nylon covers synthetic gut and multifilaments; Gut is natural gut."
    },
    "gauge": {
      "type": "string",
      "enum": [
        "16",
        "17",
        "16L",
        "18",
        "15L",
        "17L",
        "15",
        "19",
        "18L",
        "20"
      ],
      "description": "Gauge label. A higher number is thinner, and an \"L\" gauge is thinner than its base (17L is thinner than 17)."
    },
    "sort": {
      "type": "string",
      "enum": [
        "popular",
        "softest",
        "stiffest",
        "most_spin",
        "best_tension_hold",
        "most_power",
        "cheapest"
      ],
      "description": "popular (a retailer's units-sold order, default), softest, stiffest, most_spin, best_tension_hold, most_power (energy return), cheapest."
    },
    "max_price_usd": {
      "type": "number",
      "minimum": 1,
      "maximum": 1000,
      "description": "Only strings with a retail set price at or under this, in USD. Strings without a price are excluded when this is set."
    },
    "include_discontinued": {
      "type": "boolean",
      "description": "Include strings no longer sold (default false)."
    },
    "limit": {
      "type": "integer",
      "minimum": 1,
      "maximum": 10,
      "description": "How many to return (default 10)."
    }
  },
  "additionalProperties": false
}

Everything StringSpec has on one string, found by name (misspellings and missing gauges are fine): every measurement with its database percentile, elongation at 40, 51 and 62 lb, an estimated playable life, a tension adjustment versus the player's usual, how it ranks for each playing need (spin, comfort, control, power, tension hold, durability, feel), the closest alternatives, the retail price and a buy link. When the name matches several strings it returns the best match and lists the others.

{
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "maxLength": 120,
      "description": "The string's name, e.g. \"Luxilon ALU Power 16L\" or \"RPM Blast\"."
    }
  },
  "required": [
    "name"
  ],
  "additionalProperties": false
}

Side-by-side measurements, percentiles, prices and buy links for 2 or 3 strings by name, with the StringSpec comparison page when there are two.

{
  "type": "object",
  "properties": {
    "names": {
      "type": "array",
      "items": {
        "type": "string",
        "maxLength": 120
      },
      "minItems": 2,
      "maxItems": 3,
      "description": "Two or three string names."
    }
  },
  "required": [
    "names"
  ],
  "additionalProperties": false
}

Rank the database for what a player wants, with StringSpec's string finder: one main need and an optional second one (spin (More spin and shape), comfort (Easier on my arm), control (More control, less launch), power (More power and depth), hold (Plays the same for longer), durable (Lasts longer before it breaks), feel (Best feel and touch)), adjusted for the racquet (string pattern, head size, frame stiffness) and with a material ruled out if asked. Returns a shortlist with a 0-100 fit, why each string fits, its price and buy link, and the finder link with the same answers filled in. For arm or elbow pain use need "comfort", and avoid "poly" when the player wants no polyester.

{
  "type": "object",
  "properties": {
    "need": {
      "type": "string",
      "enum": [
        "spin",
        "comfort",
        "control",
        "power",
        "hold",
        "durable",
        "feel"
      ],
      "description": "The main thing the player wants."
    },
    "also": {
      "type": "string",
      "enum": [
        "spin",
        "comfort",
        "control",
        "power",
        "hold",
        "durable",
        "feel"
      ],
      "description": "An optional second need, weighted lower than the first."
    },
    "pattern": {
      "type": "string",
      "enum": [
        "open",
        "dense"
      ],
      "description": "String pattern: open (16x19 or more open) or dense (18x20 or tighter)."
    },
    "head": {
      "type": "string",
      "enum": [
        "small",
        "mid",
        "large"
      ],
      "description": "Head size: small (under 98 sq in), mid (98-100), large (100 and up)."
    },
    "frame": {
      "type": "string",
      "enum": [
        "flex",
        "avg",
        "stiff"
      ],
      "description": "Frame feel: flex (flexible, arm-friendly), avg, stiff (stiff and powerful)."
    },
    "avoid": {
      "type": "string",
      "enum": [
        "gut",
        "poly",
        "polyonly"
      ],
      "description": "gut (no natural gut), poly (no polyester), polyonly (polyester only)."
    },
    "limit": {
      "type": "integer",
      "minimum": 1,
      "maximum": 8,
      "description": "Shortlist length (default 8)."
    }
  },
  "required": [
    "need"
  ],
  "additionalProperties": false
}